MRCS Common Surgical Conditions

Topic-Wise High-Yield Revision Notes — Anatomy-style clinical chapters

78 source-derived topic chapters. Not independently specialist medically verified.

Acute Emergencies

Acute surgical emergencies

Overview. A surgical emergency requires rapid recognition of immediately reversible threats, early resuscitation, and timely definitive source control; imaging must not delay life-saving intervention.

Topic map — key distinctions

Subtopic	Defining feature / key principle
Necrotising infection	Gas gangrene or clostridial myonecrosis is a rapidly lethal necrotising soft-tissue infection.
Occupational exposure	Wash, report, test source/worker and arrange urgent HIV/HBV/HCV exposure management.
High spinal injuries	The phrenic nerve receives its principal motor supply from cervical segments C3–C5.

1. Necrotising infection

Gas gangrene or clostridial myonecrosis is a rapidly lethal necrotising soft-tissue infection. Emergency exploration and extensive debridement of devitalised muscle are essential, alongside immediate resuscitation and broad-spectrum intravenous antibiotics with clostridial coverage; repeat surgery or amputation may be required.

Clostridium perfringens is a classic cause of traumatic gas gangrene.

2. Occupational exposure

Wash, report, test source/worker and arrange urgent HIV/HBV/HCV exposure management.

HBV is substantially more transmissible per percutaneous exposure than HIV and usually more than HCV, especially from HBeAg-positive sources. Vaccination and post-exposure HBIG/vaccine decisions greatly reduce risk. Actual risk depends on source status, inoculum and host immunity.
HIV PEP should start promptly when indicated.
HBV prophylaxis depends on immunity and source status.
HBV vaccination is essential for healthcare workers.
Highest classic percutaneous infectivity in a susceptible worker: HBV.

3. High spinal injuries

The phrenic nerve receives its principal motor supply from cervical segments C3–C5. A C6 lesion may preserve diaphragm activity while interrupting descending drive to intercostal and abdominal expiratory muscles, making cough and ventilation less effective.

Clinical recognition and differential diagnosis

Pain out of proportion, rapid progression, crepitus and systemic toxicity are red flags.
Weak cough increases secretion retention and atelectasis risk.

Management and operative principles

Start intravenous antibiotics immediately, but antibiotics do not replace debridement.

Common examiner traps

The ranking changes with vaccination, viral load and exposure type; never omit source and worker serology.
Do not rely on CT or laboratory scoring to exclude necrotising infection when clinical suspicion is high.
Do not equate preserved spontaneous breathing with intact respiratory mechanics.

Rapid-recall exam pearls

Necrotising myonecrosis = urgent surgery plus immediate IV antimicrobials and resuscitation.
C6 cord injury may spare the diaphragm but still severely weaken cough.
Highest classic percutaneous infectivity in a susceptible worker: HBV.

Anaphylaxis and airway emergencies

Overview. Recognise airway compromise and systemic anaphylaxis early, treat the life-threatening physiology, and seek specialist airway support before deterioration.

Topic map — key distinctions

Subtopic	Defining feature / key principle
Recognition	ACE (kininase II) normally degrades bradykinin.

1. Recognition

ACE (kininase II) normally degrades bradykinin. ACE inhibition increases bradykinin activity and can cause angioedema without urticaria or itching. Airway protection is the priority; conventional antihistamines and corticosteroids are often ineffective for bradykinin-mediated disease.

Tongue or laryngeal swelling requires urgent airway assessment.

Common examiner traps

Do not wait for rash or rely on antihistamines as definitive treatment when the airway is threatened.

Rapid-recall exam pearls

ACE inhibitor + nonpruritic tongue swelling = consider bradykinin angioedema.

Emergency airway management

Overview. A threatened airway is a time-critical problem: assess oxygenation, the possibility of ventilation, and whether rescue access is required.

Topic map — key distinctions

Subtopic	Defining feature / key principle
Difficult intubation and oxygenation	Once optimised intubation and rescue oxygenation techniques fail in an adult CICO emergency, prompt emergency front-of-neck access is required.
Front-of-neck access	Once optimised intubation and rescue oxygenation techniques fail in an adult CICO emergency, prompt emergency front-of-neck access is required.
Neck landmarks and complications	The thyroid isthmus commonly overlies the second to fourth tracheal rings, although its position varies.

1. Difficult intubation and oxygenation

Once optimised intubation and rescue oxygenation techniques fail in an adult CICO emergency, prompt emergency front-of-neck access is required. Standard DAS algorithms use a scalpel-bougie-tube cricothyrotomy through the cricothyroid membrane, with confirmation by capnography. This differs from a planned tracheostomy through tracheal rings.

2. Front-of-neck access

The cricothyroid membrane spans the thyroid and cricoid cartilages. It is a readily accessible midline route for emergency front-of-neck airway access when oxygenation cannot otherwise be achieved.
Adult CICO emergency: cricothyroid membrane.
CICO emergency → cricothyroid membrane.
Emergency cricothyrotomy enters the airway via the cricothyroid membrane between thyroid and cricoid cartilages. It is generally quicker than a formal tracheostomy in a catastrophic adult failed-airway scenario.
The cricothyroid membrane lies between thyroid and cricoid cartilages.

3. Neck landmarks and complications

The thyroid isthmus commonly overlies the second to fourth tracheal rings, although its position varies. During open tracheostomy it may be retracted or divided with haemostasis to expose the anterior tracheal wall. The cricoid cartilage lies superior to the first tracheal ring; care is needed to avoid a very high tracheostomy and subglottic injury.

The thyroid isthmus usually overlies approximately the second to fourth tracheal rings and may require retraction or division during tracheostomy, depending on anatomy and technique.
The thyroid isthmus may cross the anterior second to fourth tracheal rings.
Thyroid isthmus typically overlies tracheal rings 2–4.
In open tracheostomy, anticipate the thyroid isthmus at rings 2–4.
Thyroid isthmus overlies the upper trachea.

Applied anatomy and pathology

A high-riding innominate artery and anterior jugular venous arch are important haemorrhage hazards.
Identify and control anterior jugular and inferior thyroid veins.

Clinical recognition and differential diagnosis

After a readiness screen, a monitored spontaneous breathing trial (SBT) assesses whether the patient can sustain ventilation with minimal or no assistance. An SBT may use a T-piece or low-level pressure support; after success, cough, secretion clearance and airway protection must still be evaluated before extubation.
Cough strength, airway patency, secretion burden, mental status and risk of post-extubation failure.
A successful SBT does not guarantee successful extubation if cough or secretion control is poor.

Investigations and diagnostic interpretation

Assess improvement of the cause of respiratory failure, oxygenation, cardiovascular stability and spontaneous effort.

Measurements, staging and thresholds

An SBT typically lasts about 30–120 minutes and is closely monitored.

Common examiner traps

CPAP and pressure support are not interchangeable with full ventilator liberation, and passing an SBT alone does not establish airway safety.
The fragmentary source “platysma cut → next layer → investing layer” omitted the operative question and did not specify the next safe plane.
Do not confuse emergency cricothyrotomy with elective tracheostomy through tracheal rings.
Do not confuse tracheostomy with cricothyrotomy through the cricothyroid membrane.
The tracheostomy opening must not be confused with the cricothyroid membrane.

Rapid-recall exam pearls

In open tracheostomy, separate strap muscles in the midline rather than dissecting laterally.
CICO is a time-critical oxygenation emergency: use trained emergency FONA without delay.
Use a readiness screen followed by an SBT; do not reflexively wean SIMV rate for days.
In open tracheostomy, anticipate the thyroid isthmus at rings 2–4.
Adult CICO emergency: cricothyroid membrane.

Shock and resuscitation

Overview. Shock is inadequate effective tissue perfusion; identify the mechanism while simultaneously correcting oxygenation, intravascular volume or circulatory obstruction.

Topic map — key distinctions

Subtopic	Defining feature / key principle
Initial resuscitation	Warmed peritoneal lavage is an invasive internal rewarming technique and is more effective at raising core temperature than passive external warming alone.

1. Initial resuscitation

Warmed peritoneal lavage is an invasive internal rewarming technique and is more effective at raising core temperature than passive external warming alone. In contemporary practice, warmed IV fluids and active external warming are common, while ECMO/extracorporeal rewarming is preferred for hypothermic cardiac arrest or severe instability when available.

Active internal warming includes warmed fluids and cavity lavage.

Applied anatomy and pathology

Phrenic nerve root values are C3, C4 and C5, with C4 dominant.

Clinical recognition and differential diagnosis

C6-level injuries generally spare diaphragm contraction but impair intercostal muscles and cough.
Thoracic segmental nerves T1–T11; abdominal muscles contribute to forced expiration and cough.
Postpartum fever and hypotension demand immediate sepsis assessment and source control.

Investigations and diagnostic interpretation

Culture identification distinguishes GAS from staphylococcal toxic shock and other postpartum pathogens.
Handle profoundly hypothermic patients gently and monitor ECG.

Management and operative principles

Penicillin plus clindamycin is commonly recommended after susceptibility and expert review, alongside urgent source control.
Management requires urgent resuscitation, antimicrobial therapy and specialist surgical/obstetric review.

Measurements, staging and thresholds

Moderate hypothermia: 28–32°C; severe usually below 28°C.

Common examiner traps

Do not interpret an older recall as saying peritoneal lavage is the universal first-line therapy for all hypothermic patients.
Postpartum collapse alone does not establish the organism; embolism, haemorrhage and other sepsis causes remain possible.

Rapid-recall exam pearls

Invasive cavity lavage can rewarm faster than passive methods, but extracorporeal support is preferred in arrest.
Invasive group A streptococcus plus rapid shock and organ failure = streptococcal toxic shock syndrome.
“C3, 4, 5 keep the diaphragm alive.”.

Trauma assessment and resuscitation

Overview. A structured trauma primary survey treats airway, breathing and circulation threats before detailed investigations or secondary assessment.

Topic map — key distinctions

Subtopic	Defining feature / key principle
Bleeding and transfusion	The patient is potentially haemorrhaging.

1. Bleeding and transfusion

The patient is potentially haemorrhaging. A structured trauma primary survey, rapid haemorrhage control, vascular access, blood samples including crossmatch and appropriately titrated blood products take priority. Bedside eFAST may help identify bleeding; CT is for patients sufficiently stable to undergo scanning.

Follow cABCDE or ABCDE with early haemorrhage control.
Activate a major haemorrhage protocol when indicated.
A systolic pressure near 100 mmHg does not exclude compensated haemorrhagic shock.
Unstable trauma: resuscitate and control haemorrhage before CT.

Investigations and diagnostic interpretation

Use warmed blood products and avoid excessive crystalloid in major bleeding.

Management and operative principles

An unstable patient with positive eFAST may need urgent operative or interventional control.

Common examiner traps

A systolic pressure near 100 mmHg does not exclude compensated haemorrhagic shock.

Rapid-recall exam pearls

Unstable trauma: resuscitate and control haemorrhage before CT.

Basic Sciences & Immunology

Applied anatomy, pathology and physiology

Overview. Basic surgical science links anatomical location and pathological mechanism to the clinical signs used in diagnosis and operative planning.

Topic map — key distinctions

Subtopic	Defining feature / key principle
Tissue pathology	Excessive oncogenic RAS signalling can trigger a protective senescence programme in otherwise checkpoint-competent cells.
Physiological response	Thiamine is an essential cofactor in carbohydrate metabolism, and deficiency is common in severe malnutrition associated with alcohol misuse.

1. Tissue pathology

Excessive oncogenic RAS signalling can trigger a protective senescence programme in otherwise checkpoint-competent cells. p16 inhibits CDK4/6, maintaining active hypophosphorylated RB, while p53-driven p21 also restrains cyclin-dependent kinases. The result is durable cell-cycle arrest that limits malignant transformation.

Senescent cells remain metabolically active and can develop a senescence-associated secretory phenotype.
Oncogenic RAS in normal checkpoint-intact cells can induce senescence rather than unchecked proliferation.

2. Physiological response

Thiamine is an essential cofactor in carbohydrate metabolism, and deficiency is common in severe malnutrition associated with alcohol misuse. It may contribute to peripheral neuropathy (dry beriberi) and predispose to Wernicke encephalopathy. Give thiamine promptly, especially before or with carbohydrate feeding in a severely deficient patient. Alcohol-related neuropathy can also reflect direct neurotoxicity and other deficiencies.

Senescent cells remain metabolically active and can develop a senescence-associated secretory phenotype.

Clinical recognition and differential diagnosis

Dry beriberi may present with peripheral neuropathy; wet beriberi may cause high-output heart failure.
Loss or functional inactivation of p53, p16 or RB checkpoint signalling.

Investigations and diagnostic interpretation

Hepatic 25-hydroxylases convert vitamin D3 to 25-hydroxyvitamin D (calcidiol), the principal circulating storage form measured to assess vitamin D status.

Common examiner traps

Do not confuse viable senescent arrest with apoptosis or simple reversible quiescence.
Do not use circulating 1,25-(OH)2D as the routine test of vitamin D stores.

Rapid-recall exam pearls

Oncogenic RAS in normal checkpoint-intact cells can induce senescence rather than unchecked proliferation.
Undernourished alcohol-dependent patient: replace thiamine before or with carbohydrate refeeding.

Immunology, histology and transplantation

Overview. Immune responses are central to infection control, tissue injury, transfusion and graft acceptance; distinguish cellular from antibody-mediated mechanisms.

Topic map — key distinctions

Subtopic	Defining feature / key principle
Cellular immunity	Histamine released from mast cells and basophils acts particularly through H1 receptors on endothelium, causing vasodilatation (partly via nitric oxide) and increased permeability of postcapillary venules.
Antibodies and complement	The Mantoux reaction reflects sensitised T lymphocytes recognising tuberculin antigens, releasing cytokines such as interferon-gamma and recruiting macrophages.
Graft and transplant	An allograft is transplanted between genetically different individuals of the same species.

1. Cellular immunity

Histamine released from mast cells and basophils acts particularly through H1 receptors on endothelium, causing vasodilatation (partly via nitric oxide) and increased permeability of postcapillary venules. It is a major early mediator of the wheal-and-flare response.

Allergen cross-linking of IgE on sensitised mast cells triggers degranulation, histamine release and other mediators, producing immediate urticaria, angioedema, bronchospasm and potentially anaphylaxis.
IgE binds high-affinity Fc-epsilon-RI on mast cells.
Memory T cells and recruited macrophages.
Mantoux = type IV hypersensitivity mediated by T cells.

2. Antibodies and complement

The Mantoux reaction reflects sensitised T lymphocytes recognising tuberculin antigens, releasing cytokines such as interferon-gamma and recruiting macrophages. The response is delayed rather than an immediate antibody-mediated event.

3. Graft and transplant

An allograft is transplanted between genetically different individuals of the same species. A cadaveric human donor valve implanted into another person is therefore a human allograft, often called a homograft.

CMV infection commonly presents during the first months after solid-organ transplantation with fever, malaise, cytopenias or organ involvement. Quantitative CMV PCR helps establish viraemia; disease assessment also requires clinical context.
Post-transplant fever + positive CMV PCR should prompt evaluation for CMV disease.

Applied anatomy and pathology

H1 receptor signalling increases endothelial permeability.
The lateral border of the tongue is a classic location.

Clinical recognition and differential diagnosis

Oral hairy leukoplakia is an EBV-associated epithelial lesion strongly linked to impaired cell-mediated immunity, especially advanced or untreated HIV infection. The characteristic corrugated lateral-tongue plaque should prompt HIV testing with consent and assessment for other causes of immunosuppression.
Hassall corpuscles are characteristic concentric epithelial structures within the medulla of the thymus, where thymocytes undergo central tolerance and maturation.
Prostaglandins contribute to pain, fever and vasodilatation.

Investigations and diagnostic interpretation

Immediate urticaria, angioedema and bronchospasm within minutes of latex exposure are characteristic of IgE-mediated type I hypersensitivity to natural-rubber latex proteins. Remove exposure, assess airway and circulation and treat suspected anaphylaxis urgently with intramuscular adrenaline as indicated.
A persistent atypical lesion may require biopsy to exclude dysplasia or malignancy.

Management and operative principles

Risk is influenced by donor/recipient serostatus and prophylaxis.
Antihistamines do not replace adrenaline in anaphylaxis.

Measurements, staging and thresholds

Rubber accelerators and other glove-manufacturing chemicals can cause allergic contact dermatitis, a delayed type IV T-cell-mediated reaction. Onset after 24–48 hours, eczematous or vesicular morphology and positive patch testing distinguish this from immediate IgE-mediated latex-protein allergy.
Read the induration, not the erythema, at 48–72 hours.

Common examiner traps

Fever and lymphadenopathy alone are not specific: the source recall lacked virological confirmation, added here to make one defensible SBA.
Isolated local swelling is not necessarily anaphylaxis; airway, breathing or circulation involvement matters.
“Glove allergy” alone cannot establish hypersensitivity type; timing and phenotype must be specified.
Do not confuse IFN-γ with type I interferons (IFN-α/β), which are prominent in antiviral signalling.
Bioprosthetic does not necessarily mean xenograft; human homograft valves are biological allografts.

Rapid-recall exam pearls

Delayed vesicular hand eczema after gloves = type IV; immediate urticaria/wheeze = type I.
Corrugated non-scrapable lateral tongue plaque = think oral hairy leukoplakia and HIV.
Post-transplant fever + positive CMV PCR should prompt evaluation for CMV disease.
IFN-γ activates macrophages; IL-4/IL-13 favour alternative macrophage activation.
Minutes + wheals/wheeze = type I; delayed eczema after glove exposure = type IV.

Pain mechanisms and inflammation

Overview. Pain results from nociceptive signalling and its modulation; inflammatory mediators, peripheral injury and neuropathic changes produce different therapeutic targets.

Topic map — key distinctions

Subtopic	Defining feature / key principle
Nociceptive signalling	Non-nociceptive large-fibre input activates inhibitory interneurones that diminish dorsal-horn projection-neurone activity.

1. Nociceptive signalling

Non-nociceptive large-fibre input activates inhibitory interneurones that diminish dorsal-horn projection-neurone activity.

Conventional TENS stimulates large-diameter low-threshold cutaneous afferents, facilitating inhibitory spinal dorsal-horn interneuronal circuits and reducing transmission of nociceptive input (gate-control theory). Descending pain-modulatory pathways may also contribute, depending on stimulation parameters.
Bradykinin, generated through the kallikrein–kinin system, contributes to vasodilatation, increased vascular permeability and pain. It acts on sensory nerve endings and can stimulate endothelial release of NO and prostacyclin. Thromboxane A2, endothelin and angiotensin II are generally vasoconstrictors.
Bradykinin causes pain, permeability and vasodilatation.

Clinical recognition and differential diagnosis

ACE degrades bradykinin; ACE-inhibitor-associated cough/angioedema partly reflects its accumulation.

Common examiner traps

Thromboxane A2 and prostacyclin have opposing platelet and vascular effects; do not confuse them.
Do not confuse TENS with spinal cord stimulation or a local anaesthetic nerve block.

Rapid-recall exam pearls

TENS works chiefly through spinal dorsal-horn modulation, not by cutting or chemically blocking nerves.
Bradykinin causes pain, permeability and vasodilatation.

Breast

Benign breast and gynaecomastia

Overview. Benign breast enlargement must be differentiated from a discrete suspicious mass; gynaecomastia reflects proliferation of glandular breast tissue in a male.

Topic map — key distinctions

Subtopic	Defining feature / key principle
Gynaecomastia mechanisms	Cirrhosis reduces hepatic metabolism of sex steroids and is associated with an increased oestrogen-to-androgen effect; alcohol-related gonadal dysfunction may contribute.
Assessment	Transient imbalance in oestrogen-androgen action during puberty commonly produces benign glandular breast enlargement.

1. Gynaecomastia mechanisms

Cirrhosis reduces hepatic metabolism of sex steroids and is associated with an increased oestrogen-to-androgen effect; alcohol-related gonadal dysfunction may contribute. This causes true glandular gynaecomastia rather than isolated fat accumulation.

Cirrhosis can cause gynaecomastia through relative oestrogen excess.
Distinguish palpable glandular disc from diffuse adipose pseudogynaecomastia.
True gynaecomastia is palpable subareolar glandular tissue.
Hard eccentric unilateral mass, nipple discharge or systemic signs are not routine pubertal gynaecomastia.

2. Assessment

Transient imbalance in oestrogen-androgen action during puberty commonly produces benign glandular breast enlargement. In an otherwise well adolescent with typical findings, reassurance and observation are usually appropriate.

Do not assume all male breast enlargement is physiological or simply adiposity.

Investigations and diagnostic interpretation

Review medications, supplements and testicular examination.

Common examiner traps

Hard eccentric unilateral mass, nipple discharge or systemic signs are not routine pubertal gynaecomastia.
Do not assume all male breast enlargement is physiological or simply adiposity.

Rapid-recall exam pearls

Pubertal bilateral subareolar enlargement is often physiological and self-limiting.
Cirrhosis can cause gynaecomastia through relative oestrogen excess.

Benign breast lesions and breast lumps

Overview. A breast lump is evaluated using concordant clinical examination, appropriate imaging and tissue sampling rather than mobility or age alone.

Topic map — key distinctions

Subtopic	Defining feature / key principle
Fibroadenoma and phyllodes	Coarse popcorn calcification is a classic benign mammographic feature of a degenerating fibroadenoma.
Cysts and fat necrosis	Simple fluid-filled cysts attenuate ultrasound less than surrounding soft tissues, so tissues deep to the cyst receive relatively greater acoustic energy and appear brighter: posterior acoustic enhancement.
Mastitis and abscess	Lactational mastitis is inflammation of the lactating breast, frequently associated with milk stasis or bacterial infection, presenting with painful erythema and systemic symptoms.
Risk and triple assessment	Fibrocystic change commonly produces cyclical mastalgia and diffuse nodularity related to hormonal fluctuations.

1. Fibroadenoma and phyllodes

Coarse popcorn calcification is a classic benign mammographic feature of a degenerating fibroadenoma. Malignant lesions are more concerning when microcalcifications are fine pleomorphic, fine linear or branching, especially in suspicious distributions.

Fibroadenoma is a benign fibroepithelial tumour, common in young women, classically rubbery, well-circumscribed and mobile. Diagnosis should be established by age-appropriate triple assessment rather than palpation alone.
Young woman + mobile rubbery mass = fibroadenoma.
Popcorn calcification = involuting fibroadenoma.

2. Cysts and fat necrosis

Simple fluid-filled cysts attenuate ultrasound less than surrounding soft tissues, so tissues deep to the cyst receive relatively greater acoustic energy and appear brighter: posterior acoustic enhancement. The combination of anechoic content, circumscribed thin wall and no solid vascular component supports a simple cyst. Any suspicious solid component or discordant examination requires further assessment.

Fat necrosis follows trauma, surgery or radiotherapy and can cause a palpable mass, skin tethering and calcification. Characteristic oil cysts with eggshell/rim calcification favour the benign diagnosis, although indeterminate imaging requires biopsy.
Postoperative lump plus characteristic oil cyst suggests fat necrosis.
In women younger than 30, targeted ultrasound is usually the first imaging test for a palpable mass. It distinguishes cystic from solid lesions without ionising radiation and guides biopsy when suspicious features are present.
Fibrocystic change commonly produces cyclical mastalgia and diffuse nodularity related to hormonal fluctuations. The clinical pattern is typically bilateral and varies with the menstrual cycle. A persistent discrete lump or red flags still require age-appropriate triple assessment.
Fibrocystic breast change is a benign spectrum that commonly includes stromal fibrosis, cyst formation, apocrine metaplasia and sometimes adenosis or epithelial hyperplasia. Apocrine metaplastic cells have abundant granular eosinophilic cytoplasm. The clinical and histological features fit this spectrum.
A thin-walled anechoic lesion with posterior acoustic enhancement is typical of a simple breast cyst. Cysts are common around the perimenopause and may be tender or fluctuate with hormonal change. A clinically suspicious or discordant lesion still requires appropriate assessment.

3. Mastitis and abscess

Lactational mastitis is inflammation of the lactating breast, frequently associated with milk stasis or bacterial infection, presenting with painful erythema and systemic symptoms. A focal fluctuant area or non-resolution should prompt evaluation for abscess.

Fever and diffuse breast erythema during breastfeeding suggest lactational mastitis.
Provide analgesia and supportive care and use antibiotics when bacterial mastitis is suspected.

4. Risk and triple assessment

Fibrocystic change commonly produces cyclical mastalgia and diffuse nodularity related to hormonal fluctuations. The clinical pattern is typically bilateral and varies with the menstrual cycle. A persistent discrete lump or red flags still require age-appropriate triple assessment.

BI-RADS 5 + new palpable mass = tissue diagnosis, usually image-guided core biopsy.
Triple assessment combines clinical assessment, appropriate imaging and pathology when indicated.
Triple assessment combines clinical examination, appropriate imaging and tissue sampling.
Implants do not remove the need for triple assessment of a suspicious lump.
Triple assessment remains necessary for suspicious clinical findings.
Never dismiss a suspicious postoperative mass without concordant triple assessment.

Applied anatomy and pathology

A simple cyst is typically anechoic, thin-walled and shows posterior acoustic enhancement.
Posterior enhancement and absence of internal solid tissue support a simple cyst.
Simple cyst: anechoic, circumscribed, thin wall and posterior enhancement.

Clinical recognition and differential diagnosis

Late first full-term pregnancy delays the lasting pregnancy-related differentiation of breast epithelium and is associated with greater lifetime breast cancer risk than an earlier first birth. Most breast cancers occur without a strong family history.
Late first full-term pregnancy is associated with a higher long-term breast cancer risk compared with earlier first full-term pregnancy, although reproductive risk relationships vary by age and tumour subtype.
High-risk genetics changes surveillance and counselling but not the need to diagnose a suspicious mass.

Investigations and diagnostic interpretation

Contrast-enhanced breast MRI has high sensitivity and is used in appropriately selected high-risk women, often alongside mammography depending on age and genetic risk. Screening eligibility should follow specialised risk stratification and national guidance.
Clinical assessment and imaging have identified a highly suspicious solid lesion. Image-guided core biopsy supplies tissue architecture and permits ER, PR and HER2 assessment, unlike imaging alone. A BRCA1 mutation increases pretest risk but does not replace histological confirmation.
For a palpable mass in a woman younger than 30, targeted ultrasound is usually the initial imaging test, including when implants are present. Suspicious findings require appropriate image-guided biopsy and potentially additional mammography or MRI.
Suspicious or clinically discordant findings require tissue diagnosis despite a benign-looking scan.

Measurements, staging and thresholds

ER positivity identifies a biologic subtype that often has a more favourable course than comparable ER-negative disease and predicts benefit from endocrine treatment. Prognosis must still integrate stage, grade, HER2 status and other factors.
Tumour grade reflects tubule formation, nuclear pleomorphism and mitotic activity.
Age <30 years: targeted ultrasound is usually the first imaging test.

Common examiner traps

Do not attribute the increased cancer risk of atypical epithelial hyperplasia to all simple fibrocystic changes.
A normal ultrasound does not automatically exclude malignancy if the palpable finding remains suspicious.
Inflammatory breast cancer and abscess should be considered if symptoms persist or fail to improve.
A mobile mass is not automatically benign; discordant imaging or clinical findings warrant biopsy.
Prognostic and predictive markers are not identical concepts; receptor status has both roles.

Rapid-recall exam pearls

Non-bloody cyst fluid + complete disappearance + concordant imaging = no immediate intervention.
Cysts + stromal fibrosis + apocrine metaplasia strongly suggest fibrocystic breast change.
High inherited risk may justify MRI surveillance, not MRI for every woman with implants.
Fever and diffuse breast erythema during breastfeeding suggest lactational mastitis.
Later first childbirth increases breast cancer risk relative to earlier childbirth.

Breast carcinoma, DCIS and staging

Overview. Management of breast malignancy integrates tumour stage, histological grade, nodal status, receptor biology and patient-specific treatment priorities.

Topic map — key distinctions

Subtopic	Defining feature / key principle
Axillary staging and nerve injuries	The long thoracic nerve (C5–C7) travels along the superficial surface of serratus anterior and is vulnerable during axillary dissection.
Receptor biology and genetics	Oestrogen-receptor positivity is a predictive biomarker for benefit from endocrine treatment, and also contributes to biological prognosis.
Systemic treatment and spread	Oestrogen-receptor positivity is a predictive biomarker for benefit from endocrine treatment, and also contributes to biological prognosis.
Inflammatory malignancy	Inflammatory breast cancer causes rapid breast erythema and oedema from dermal lymphatic tumour involvement.

1. Axillary staging and nerve injuries

The long thoracic nerve (C5–C7) travels along the superficial surface of serratus anterior and is vulnerable during axillary dissection. Serratus anterior holds the medial scapular border against the thoracic wall and protracts/upwardly rotates the scapula. Paralysis produces medial winging accentuated by pushing.

The long thoracic nerve is a direct branch of the C5, C6 and C7 anterior rami, arising proximal to formation of the brachial plexus trunks. It runs down the lateral chest wall to innervate serratus anterior. Axillary surgery can injure it, producing medial scapular winging and difficulty with overhead elevation.
Post-axillary surgery medial scapular winging = long thoracic nerve/serratus anterior.
The axillary vein is the superior boundary of standard axillary lymph-node clearance. Level I nodes lie lateral to pectoralis minor, level II behind it and level III medial to it. Important structures to preserve include the long thoracic and thoracodorsal nerves.
Sentinel-node biopsy reduces morbidity compared with routine axillary clearance in suitable patients.
A positive sentinel node does not always mandate complete axillary dissection.
Long thoracic nerve supplies serratus anterior.

2. Receptor biology and genetics

Oestrogen-receptor positivity is a predictive biomarker for benefit from endocrine treatment, and also contributes to biological prognosis. Strong diffuse ER expression makes endocrine sensitivity more likely. The need for radiotherapy, chemotherapy and nodal treatment still depends on stage, grade, other biomarkers and patient factors; ER expression alone does not settle those decisions.

ER, PR, HER2 and other genomic/pathological features when indicated.
Oestrogen-receptor positivity identifies a biologically actionable subgroup that can benefit from adjuvant endocrine therapy and is often associated with a more favourable course than otherwise similar receptor-negative tumours. Prognosis still requires stage, grade, HER2 and other factors.
Do not confuse serum markers with ER, PR and HER2 receptor testing used to guide treatment.
BRCA1 is a tumour-suppressor gene involved in homologous-recombination repair of double-stranded DNA breaks. Pathogenic germline variants substantially increase lifetime breast and ovarian cancer risks, with management based on personalised genetics assessment.
Node-positive HER2-positive invasive breast cancer benefits from chemotherapy and HER2-directed therapy. Trastuzumab is a key component; pertuzumab may be added for eligible node-positive cases according to guidance.
Pathogenic BRCA2 variants are associated with hereditary breast, ovarian, pancreatic and prostate cancer and can confer increased risk of aggressive prostate malignancy.

3. Systemic treatment and spread

Node-positive HER2-positive invasive breast cancer benefits from chemotherapy and HER2-directed therapy. Trastuzumab is a key component; pertuzumab may be added for eligible node-positive cases according to guidance.
For postmenopausal ER-positive invasive breast cancer at medium or high recurrence risk, an aromatase inhibitor is an appropriate initial adjuvant endocrine treatment. It reduces peripheral oestrogen synthesis and lowers recurrence risk; the complete oncological plan also considers chemotherapy and radiotherapy as indicated.
Baseline and interval cardiac function assessment are important with trastuzumab.

4. Inflammatory malignancy

Inflammatory breast cancer causes rapid breast erythema and oedema from dermal lymphatic tumour involvement. Lactation does not exclude malignancy; non-resolving inflammatory changes need prompt imaging and tissue assessment.

Non-resolving mastitis-like change + peau d’orange = exclude inflammatory cancer.
Do not call every erythematous postoperative lesion inflammatory breast cancer or benign dermatitis.

Applied anatomy and pathology

Breast carcinoma skeletal metastases are commonly osteolytic, reflecting osteoclast activation; they can also be mixed lytic-sclerotic or sclerotic, particularly after treatment. This contrasts with the classically osteoblastic pattern of prostate carcinoma, although exceptions exist.
The thoracodorsal nerve supplies latissimus dorsi; injury weakens shoulder extension, adduction and internal rotation.
Serratus anterior protracts and upwardly rotates the scapula and holds its medial border against the thorax.

Clinical recognition and differential diagnosis

Osteolytic skeletal metastases can cause cancer-associated hypercalcaemia by accelerating bone resorption. Symptoms include dehydration, constipation, polyuria, weakness and confusion. Severe cases require prompt isotonic fluids and antiresorptive therapy as appropriate.
The intercostobrachial nerve, usually the lateral cutaneous branch of T2, crosses the axilla and supplies sensation to the upper medial arm. It may be divided during clearance if necessary, causing numbness or neuropathic pain, but modern nerve-sparing dissection attempts to preserve it.
Alcohol consumption is a modifiable risk factor for breast cancer, with risk generally increasing with intake. Avoidance or reduction can lower alcohol-attributable risk. Family history warrants a separate formal inherited-risk assessment and appropriate surveillance advice.

Investigations and diagnostic interpretation

CEA can be elevated in metastatic breast cancer but lacks the diagnostic performance needed for population screening or primary diagnosis. Diagnosis relies on clinical assessment, appropriate imaging and tissue biopsy. CA 15-3 is another sometimes-used marker in selected advanced disease contexts.
New persistent nodules at a prior cancer surgical site raise concern for locoregional cutaneous recurrence. Tissue diagnosis, often punch or core biopsy, is required; confirmed recurrent disease should be restaged and ER/PR/HER2 status reassessed when feasible.
Core biopsy establishes invasive carcinoma; skin biopsy may support but a negative skin sample does not exclude it.
Immunohistochemistry with in-situ hybridisation for equivocal cases, using current laboratory reporting standards.

Management and operative principles

Superficial lymphatics of the anterior abdominal wall above the umbilicus usually drain toward axillary nodes; below the umbilicus they predominantly drain to superficial inguinal nodes.
Germline findings may influence surveillance, risk-reducing surgery and systemic treatment.
Lifestyle advice does not replace appropriate surveillance or genetic counselling.
Persistent inflammation despite treatment requires urgent referral.

Measurements, staging and thresholds

The presence and burden of axillary nodal metastasis are major determinants of anatomical stage, recurrence risk and adjuvant management. Modern prognostication integrates nodal status, tumour size, grade, hormone receptors and HER2 rather than relying on one factor alone.
Hormone-receptor-positive tumours are biologically heterogeneous but generally have more treatment options and often a more favourable prognosis than receptor-negative tumours of otherwise similar stage and grade. Oestrogen-receptor expression predicts benefit from endocrine therapy.
Regional nodal involvement is a major determinant of anatomic stage and prognosis in invasive breast carcinoma. Modern prognostic staging also incorporates tumour size, grade, ER, PR, HER2 and in selected situations gene-expression assays.
The sentinel node is the initial draining nodal basin most likely to contain early lymphatic metastases. Mapping with tracer or dye permits focused staging in selected clinically node-negative breast cancer patients.

Common examiner traps

An isolated mental nerve lesion can occur distally in the mandible; the added skull-base imaging localises this particular question.
A paternal transmission route can also convey BRCA mutations; absence of cancer in a male relative does not exclude carriage.
Do not treat the lytic/blastic distinction as absolute or use it instead of tissue diagnosis and appropriate staging.
Do not confuse the strongest traditional staging factor with a biomarker predicting response to endocrine therapy.
Do not describe ER positivity as universally favourable independent of stage, grade or duration of follow-up.

Rapid-recall exam pearls

Five involved axillary nodes after mastectomy: radiotherapy is a locoregional indication, not a substitute for systemic treatment.
Alcohol reduction is evidence-based; caffeine restriction is not a proven breast cancer prevention strategy.
Postmenopausal ER-positive, higher-risk invasive breast cancer: consider an adjuvant aromatase inhibitor.
BRCA1/BRCA2 are DNA-repair tumour-suppressor genes implicated in hereditary breast/ovarian cancer.
Breast cancer prognosis is driven by stage and biology, especially nodes and tumour features.

Breast imaging and tissue diagnosis

Overview. Imaging and biopsy answer different questions: radiology localises and characterises a lesion, while pathology establishes the tissue diagnosis.

Topic map — key distinctions

Subtopic	Defining feature / key principle
Ultrasound versus mammography	Suspicious calcifications visible only on mammography require image-guided tissue sampling directed at the calcifications.
Biopsy techniques	UK core categories: B1 normal/non-representative, B2 benign, B3 uncertain malignant potential, B4 suspicious, B5 malignant.
Reporting and concordance	BI-RADS 4 indicates a suspicious abnormality for which biopsy is recommended.

1. Ultrasound versus mammography

Suspicious calcifications visible only on mammography require image-guided tissue sampling directed at the calcifications. Stereotactic vacuum-assisted or core biopsy permits diagnosis of DCIS or invasive malignancy and specimen radiography can confirm retrieval of calcifications.

Stereotactic biopsy may target mammographic calcifications without ultrasound correlate.
Ultrasound may not show mammographic calcifications.
A suspicious ultrasound-visible lesion requires tissue sampling despite a negative mammogram. Ultrasound-guided core biopsy provides histology and, when cancer is identified, receptor assessment. Imaging and clinical findings must be correlated; negative mammography does not negate BI-RADS 4 ultrasound findings.
Ultrasound-guided core biopsy is useful for sonographically visible masses.
A negative mammogram does not overrule a suspicious targeted ultrasound.

2. Biopsy techniques

UK core categories: B1 normal/non-representative, B2 benign, B3 uncertain malignant potential, B4 suspicious, B5 malignant.

Core needle biopsy is preferred over FNAC alone for a suspicious solid breast mass.
A suspicious ultrasound-visible lesion requires tissue sampling despite a negative mammogram. Ultrasound-guided core biopsy provides histology and, when cancer is identified, receptor assessment. Imaging and clinical findings must be correlated; negative mammography does not negate BI-RADS 4 ultrasound findings.
Core needle biopsy preserves tissue architecture, distinguishes invasive from in-situ disease when adequately sampled, and permits ER, PR and HER2 testing. It is the standard tissue sampling method for most suspicious solid breast lesions.
Dermal lymphatic invasion can be patchy, so clinical and core-biopsy findings remain essential.
Core biopsy can distinguish in situ from invasive disease when sufficiently representative.

3. Reporting and concordance

BI-RADS 4 indicates a suspicious abnormality for which biopsy is recommended.
BI-RADS 5 indicates very high suspicion of malignancy.
A suspicious ultrasound-visible lesion requires tissue sampling despite a negative mammogram. Ultrasound-guided core biopsy provides histology and, when cancer is identified, receptor assessment. Imaging and clinical findings must be correlated; negative mammography does not negate BI-RADS 4 ultrasound findings.

Applied anatomy and pathology

Oestrogen receptor, progesterone receptor and HER2; Ki-67 may provide additional context.

Clinical recognition and differential diagnosis

Inflammatory carcinoma can lack a discrete palpable mass.

Investigations and diagnostic interpretation

B4 is suspicious but not a definitive malignant histological diagnosis. Radiology–pathology concordance should be reviewed in a breast MDT and further representative tissue obtained before definitive cancer treatment.
A specific benign histological diagnosis that adequately explains the imaging and clinical appearance.
Diagnosis relies on rapid clinical evolution, imaging and tissue evidence of invasive carcinoma.
Dermal lymphatic tumour emboli are characteristic but not mandatory in every skin punch biopsy.

Measurements, staging and thresholds

Core samples permit tumour grade and receptor assessment.

Common examiner traps

An inflammatory appearance is not proof of infection; persistent unilateral changes require malignancy assessment.
Do not proceed directly to mastectomy on the basis of calcifications without histology.
Do not interpret a benign report in isolation from the mammogram and ultrasound.
Do not confuse core biopsy with excisional surgery or nipple/skin punch biopsy.
Do not confuse day-seven proliferation with the late scar-remodelling phase.

Rapid-recall exam pearls

If the suspicious lesion is seen only on mammography, biopsy under mammographic/stereotactic guidance.
Peau d’orange in inflammatory breast cancer = dermal lymphatic tumour emboli and oedema.
Core needle biopsy is preferred over FNAC alone for a suspicious solid breast mass.
Granulation tissue at one week is highly vascular and rich in fibroblasts.
Discordant benign core biopsy of a suspicious lesion requires re-sampling.

Breast reconstruction and surgery

Overview. Implant-related symptoms require a separate assessment from suspected malignancy; implant integrity studies do not substitute for cancer triple assessment.

Topic map — key distinctions

Subtopic	Defining feature / key principle
Silicone implant rupture	MRI with silicone-specific sequences is highly sensitive for intracapsular silicone implant rupture when ultrasound is equivocal.
Imaging implant integrity	MRI with silicone-specific sequences is highly sensitive for intracapsular silicone implant rupture when ultrasound is equivocal.
Separate cancer assessment	MRI with silicone-specific sequences is highly sensitive for intracapsular silicone implant rupture when ultrasound is equivocal.

1. Silicone implant rupture

MRI with silicone-specific sequences is highly sensitive for intracapsular silicone implant rupture when ultrasound is equivocal. This question concerns implant integrity, not assessment of a palpable suspicious breast mass: the latter follows age-appropriate targeted breast imaging and triple assessment. Silicone rupture may produce the MRI linguine sign from collapsed implant shell.

Indeterminate silicone implant rupture → implant-protocol MRI.

2. Imaging implant integrity

Indeterminate silicone implant rupture → implant-protocol MRI.
Do not replace targeted imaging and biopsy of a suspicious lump with MRI solely because implants are present.
Differentiate implant-integrity assessment from cancer evaluation of a breast lump.
Curvilinear collapsed implant-shell fragments within the silicone gel.

3. Separate cancer assessment

Investigations and diagnostic interpretation

New masses, late seromas or suspicious nodes require separate malignancy work-up.
MRI can show intracapsular rupture with the linguine sign.
Ultrasound is often useful as an initial assessment.

Common examiner traps

Do not replace targeted imaging and biopsy of a suspicious lump with MRI solely because implants are present.

Rapid-recall exam pearls

Indeterminate silicone implant rupture → implant-protocol MRI.

Nipple discharge and ductal disease

Overview. Nipple discharge is stratified by laterality, spontaneity, number of ducts and whether the fluid is bloody, serous or thick; concerning presentations require assessment for neoplasia.

Topic map — key distinctions

Subtopic	Defining feature / key principle
Duct ectasia	Periductal inflammation and dilatation of major subareolar ducts lead to thick, sticky, often green or creamy discharge.
Intraductal papilloma	An intraductal papilloma is a benign papillary epithelial proliferation within a milk duct.
Paget disease of nipple	Mammary Paget disease represents malignant glandular cells infiltrating the nipple epidermis and often overlies DCIS or invasive ductal carcinoma.
DCIS and malignancy	Ductal carcinoma in situ is malignant epithelial proliferation confined within ducts by an intact basement membrane.
Imaging and excision	In a woman aged 40 or older with pathological nipple discharge, diagnostic mammography or digital breast tomosynthesis is an appropriate initial imaging test, generally complemented by targeted ultrasound.

1. Duct ectasia

Periductal inflammation and dilatation of major subareolar ducts lead to thick, sticky, often green or creamy discharge. It is common around the perimenopausal years, and a subareolar mass or nipple inversion may coexist.

Duct ectasia and periductal mastitis overlap clinically and histologically; the latter more often has painful inflammation.
Do not confuse uncomplicated duct ectasia in an older patient with an actively inflamed, painful periductal process; neither excludes cancer without assessment.
Duct ectasia itself is a benign inflammatory condition.
Thick multicoloured discharge suggests duct ectasia; bloody single-duct discharge suggests papilloma or malignancy.
Duct ectasia can retract the nipple, but a hard irregular fixed mass changes the pre-test probability.

2. Intraductal papilloma

An intraductal papilloma is a benign papillary epithelial proliferation within a milk duct. A central solitary papilloma can cause spontaneous unilateral clear or bloody single-duct discharge. Because malignancy can produce the same symptom, age-appropriate breast imaging and tissue diagnosis are essential.

Thick multicoloured discharge suggests duct ectasia; bloody single-duct discharge suggests papilloma or malignancy.
Unilateral spontaneous bloody single-duct discharge suggests papilloma but requires malignancy exclusion.
Never assume a bloody nipple discharge is benign merely because papilloma is a classic examination answer.
Management of biopsy-proven papilloma depends on atypia, imaging-pathology concordance and symptoms.
A benign papilloma cannot be diagnosed reliably from discharge colour alone.

3. Paget disease of nipple

Mammary Paget disease represents malignant glandular cells infiltrating the nipple epidermis and often overlies DCIS or invasive ductal carcinoma. Persistent unilateral nipple eczema requires prompt clinical assessment and biopsy.

Paget disease can resemble chronic eczema but is often unilateral and persistent.
Persistent unilateral nipple eczema: exclude Paget disease and underlying carcinoma.
Unilateral persistent nipple eczema → biopsy for Paget disease.
Mammary Paget disease involves malignant cells within nipple epidermis and is frequently associated with underlying ductal carcinoma, even when mammography or palpation is unremarkable. A nipple skin biopsy is required.
Histological examination of a biopsy of the affected nipple/areola identifies malignant Paget cells in the epidermis. Breast imaging is additionally needed to assess associated underlying carcinoma.
Large pale malignant Paget cells within epidermis.

4. DCIS and malignancy

Ductal carcinoma in situ is malignant epithelial proliferation confined within ducts by an intact basement membrane. DCIS commonly presents mammographically as suspicious microcalcifications rather than a palpable mass.

Mammary Paget disease represents malignant glandular cells infiltrating the nipple epidermis and often overlies DCIS or invasive ductal carcinoma. Persistent unilateral nipple eczema requires prompt clinical assessment and biopsy.
Investigate for underlying DCIS or invasive carcinoma.
Underlying DCIS or invasive carcinoma is common.
Do not confuse DCIS (non-invasive) with invasive ductal/NST carcinoma.
NICE recommends offering sentinel lymph node biopsy to people having mastectomy for DCIS. Core biopsy can under-sample an invasive focus, and lymphatic mapping may be disrupted after mastectomy. By contrast, routine sentinel biopsy is generally not needed for low-risk DCIS treated by breast-conserving surgery.
DCIS is a non-invasive epithelial malignancy confined within ducts.

5. Imaging and excision

In a woman aged 40 or older with pathological nipple discharge, diagnostic mammography or digital breast tomosynthesis is an appropriate initial imaging test, generally complemented by targeted ultrasound. A normal ultrasound does not exclude ductal or mammographically visible malignancy. Persistent suspicious findings require specialist triple assessment and tissue diagnosis when a target is found.

Clinical assessment, mammography and/or ultrasound as appropriate, and image-guided or clinically guided tissue sampling.
At ages 30–39, ultrasound and/or diagnostic mammography may be appropriate depending on circumstances.
At age 40 or older, mammography/DBT and ultrasound are complementary first-line investigations.
Ultrasound and mammography are selected according to age and clinical findings.
Negative mammography/ultrasound does not fully exclude intraductal pathology.
Mammography and ultrasound assess underlying disease.

Applied anatomy and pathology

A persistent cutaneous opening with recurrent discharge following periareolar inflammation or piercing suggests a mammary duct fistula. A fistula may follow recurrent periductal sepsis and may require specialist evaluation and tract/duct treatment if persistent.
Ductal carcinoma in situ consists of neoplastic epithelial proliferation confined to the mammary duct-lobular system without stromal invasion. Preservation of the basement membrane and myoepithelial layer supports an in-situ lesion; invasive carcinoma breaches these boundaries.
Definitive treatment may require excision of the affected duct/fistula tract after inflammation settles.

Clinical recognition and differential diagnosis

Invasive carcinoma of no special type, historically called invasive ductal carcinoma, is the most common invasive breast cancer. Infiltrative malignant glands and cords are typical; invasive lobular carcinoma more often shows discohesive single-file cells associated with loss of E-cadherin.
A new dominant mass, spontaneous bloody discharge, skin/nipple distortion or progressive focal symptoms.
Periductal mastitis is associated with tobacco smoking, particularly in younger patients.

Investigations and diagnostic interpretation

When clinical examination and age-appropriate targeted imaging are reassuring, isolated breast pain is usually benign. Explanation, supportive bra advice, topical or oral analgesia when suitable and review for changing symptoms are appropriate.
Fine pleomorphic or linear branching calcifications following a ductal distribution can reflect necrotic debris and calcification within ducts affected by DCIS. Tissue sampling is required because imaging cannot prove the histology.
Typical cyclical nonfocal pain with normal examination generally needs reassurance and symptomatic care rather than routine imaging.
Pathological discharge is typically spontaneous, unilateral, persistent, single-duct or bloody.

Management and operative principles

Recurrent disease may cause a mammary duct fistula and require specialist surgical management.
Removal of the breast disrupts normal lymphatic drainage and sentinel mapping.

Measurements, staging and thresholds

Atypical ductal hyperplasia is a proliferative lesion with cytological and architectural similarity to low-grade DCIS but less extensive involvement. It confers a significantly elevated long-term risk of breast cancer.
Oestrogen receptor, progesterone receptor and HER2, alongside histological grade and stage.
Under 30 years: targeted ultrasound is generally the first imaging study if indicated.
Histological grade, stage and ER/PR/HER2 status guide prognosis and treatment.

Common examiner traps

Do not confuse uncomplicated duct ectasia in an older patient with an actively inflamed, painful periductal process; neither excludes cancer without assessment.
Do not equate negative imaging with zero malignancy risk, but do not claim all such patients require duct excision.
Never assume a bloody nipple discharge is benign merely because papilloma is a classic examination answer.
Do not treat a normal targeted ultrasound as definitive reassurance in a patient with nipple retraction.
A benign-appearing lump or benign FNAC alone must not override discordant clinical or imaging findings.

Rapid-recall exam pearls

Thick multicoloured discharge suggests duct ectasia; bloody single-duct discharge suggests papilloma or malignancy.
Bloody unilateral discharge at age 42 with only a negative ultrasound still requires diagnostic mammography/DBT.
Unilateral spontaneous bloody single-duct discharge suggests papilloma but requires malignancy exclusion.
Persistent single-duct bloody discharge requires a breast pathway, even if imaging is normal.
Diffuse cyclical mastalgia + normal examination: reassurance, not routine advanced imaging.

Cardiopulmonary

Cardiac anatomy, physiology and disease

Overview. Cardiac output depends on preload, afterload, contractility and heart rate; anatomical defects and rhythm disturbances may alter surgical risk and haemodynamics.

Topic map — key distinctions

Subtopic	Defining feature / key principle
Coronary and valvular anatomy	The fibrosa of cardiac valve leaflets is collagen-rich connective tissue that withstands mechanical stress.
Haemodynamic physiology	Intra-aortic balloon counterpulsation augments diastolic aortic pressure and coronary perfusion, then deflates before systole to reduce left-ventricular afterload.
Dysrhythmia and ischaemia	Proximal subclavian stenosis reduces inflow to the left internal thoracic (mammary) graft.

1. Coronary and valvular anatomy

The fibrosa of cardiac valve leaflets is collagen-rich connective tissue that withstands mechanical stress. Other layers include a proteoglycan-rich spongiosa and an elastin-rich ventricularis or atrialis.

Severe aortic stenosis creates fixed left-ventricular outflow obstruction. Chronic pressure overload causes concentric hypertrophy and reduced compliance, raising LV end-diastolic and left-atrial pressures and leading to pulmonary venous congestion, even before marked systolic impairment.
Intra-aortic balloon counterpulsation augments diastolic aortic pressure and coronary perfusion, then deflates before systole to reduce left-ventricular afterload. Its use is selective; routine use in all infarct-related cardiogenic shock has not shown a survival benefit.
The right ventricle occupies most of the sternocostal cardiac surface and lies directly behind the sternum. The left ventricle mainly forms the apex and much of the diaphragmatic surface; the right atrium makes most of the right cardiac border.
Valvular leaflets are specialised layers of extracellular matrix with collagen-rich fibrosa providing tensile strength, proteoglycan-rich spongiosa cushioning stress and an elastin-rich ventricularis or atrialis aiding recoil.
The right coronary artery normally originates from the right coronary (anterior) sinus of Valsalva, superior to the aortic valve cusp. The left main coronary artery originates from the left coronary sinus.
The RCA usually runs in the right atrioventricular groove.

2. Haemodynamic physiology

Intra-aortic balloon counterpulsation augments diastolic aortic pressure and coronary perfusion, then deflates before systole to reduce left-ventricular afterload. Its use is selective; routine use in all infarct-related cardiogenic shock has not shown a survival benefit.

Proximal subclavian stenosis reduces inflow to the left internal thoracic (mammary) graft. During arm exercise, low distal subclavian pressure can reverse flow from the coronary graft toward the arm, producing myocardial ischaemia: coronary–subclavian steal.
Severe aortic stenosis creates fixed left-ventricular outflow obstruction. Chronic pressure overload causes concentric hypertrophy and reduced compliance, raising LV end-diastolic and left-atrial pressures and leading to pulmonary venous congestion, even before marked systolic impairment.
Measure both arm pressures when suspecting subclavian disease.
Diastolic inflation augments coronary perfusion pressure.
Concentric LV hypertrophy reflects pressure overload.
Severe AS can cause pulmonary oedema through diastolic dysfunction and high filling pressures.

3. Dysrhythmia and ischaemia

Proximal subclavian stenosis reduces inflow to the left internal thoracic (mammary) graft. During arm exercise, low distal subclavian pressure can reverse flow from the coronary graft toward the arm, producing myocardial ischaemia: coronary–subclavian steal.

Isoprenaline directly stimulates cardiac beta-adrenergic receptors and can increase sinus rate in the denervated transplanted heart. Atropine and glycopyrrolate depend on blocking vagal effects and are usually ineffective after transplantation. Unstable bradycardia requires immediate resuscitation and pacing consideration.
Intra-aortic balloon counterpulsation augments diastolic aortic pressure and coronary perfusion, then deflates before systole to reduce left-ventricular afterload. Its use is selective; routine use in all infarct-related cardiogenic shock has not shown a survival benefit.
Valvular leaflets are specialised layers of extracellular matrix with collagen-rich fibrosa providing tensile strength, proteoglycan-rich spongiosa cushioning stress and an elastin-rich ventricularis or atrialis aiding recoil.
The fibrosa of cardiac valve leaflets is collagen-rich connective tissue that withstands mechanical stress. Other layers include a proteoglycan-rich spongiosa and an elastin-rich ventricularis or atrialis.
Diastolic coronary augmentation and systolic afterload reduction.
The left internal thoracic artery commonly grafts the LAD.

Applied anatomy and pathology

Angiotensin II binds AT1 receptors on vascular smooth muscle, producing potent vasoconstriction. It also stimulates aldosterone secretion, enhances sodium retention and supports sympathetic effects. Bradykinin, ANP and nitric oxide generally oppose vasoconstriction.
Coronary dominance depends on the origin of the posterior descending artery.
The right ventricle is particularly exposed to blunt anterior chest trauma.

Clinical recognition and differential diagnosis

Exertional angina, syncope and dyspnoea are classic symptomatic severe AS presentations.
Loss of atrial contribution to LV filling can sharply reduce preload and cardiac output.
Marfan syndrome is associated with FBN1-related aortic root disease.

Investigations and diagnostic interpretation

Pregnancy increases haemodynamic stress on the aorta, especially in patients with heritable aortopathy such as Marfan syndrome. Sudden severe chest/back pain warrants immediate assessment for aortic dissection; urgent maternal imaging and multidisciplinary management are required.
Urgent aortic imaging should not be delayed solely because of pregnancy when dissection is suspected.
Valve calcification is pathological, not evidence that normal cusps are cartilage.
The right atrium forms the right heart border on a frontal radiograph.

Management and operative principles

Any dissection involving the ascending aorta, generally requiring emergency surgical assessment.
Endovascular or surgical revascularisation based on anatomy and patient factors.
Definitive management is surgical repair.

Measurements, staging and thresholds

Concordant Doppler measurements (peak velocity at least 4.0 m/s, mean gradient at least 40 mmHg and valve area at most 1.0 cm²) identify severe high-gradient aortic stenosis. Aortic sclerosis is leaflet thickening/calcification without major haemodynamic obstruction and does not produce these severe gradients.
High-gradient severe AS: Vmax ≥4.0 m/s and/or mean gradient ≥40 mmHg with supportive valve area ≤1.0 cm².

Common examiner traps

Do not confuse increased bradykinin after ACE inhibition with the direct pressor effect of angiotensin II.
A systolic ejection murmur is not the same as the pansystolic murmur of mitral regurgitation.
A distal subclavian lesion is not equivalent to one proximal to the mammary graft origin.
Do not mistake pathological calcification or ossification for normal valvular cartilage.
Do not confuse autonomic innervation with the location or origin of the pacemaker cells.

Rapid-recall exam pearls

After heart transplantation, atropine is often ineffective; direct beta stimulation or pacing may be needed.
Severe AS can cause pulmonary oedema through diastolic dysfunction and high filling pressures.
Cardiac contraction requires extracellular trigger calcium; skeletal muscle coupling differs.
Pregnant patient with Marfanoid features and tearing chest pain: rule out dissection.
Post-LIMA CABG + left-arm exertional angina = proximal left subclavian stenosis.

Cardiac disease and heart valves

Overview. Valve stenosis and regurgitation create distinct pressure or volume overload patterns; interpret murmurs alongside symptoms and echocardiography.

Topic map — key distinctions

Subtopic	Defining feature / key principle
Aortic stenosis	Symptomatic severe aortic stenosis creates substantial risk of perioperative hypotension, myocardial ischaemia and haemodynamic collapse.
Preoperative risk	Symptomatic severe aortic stenosis creates substantial risk of perioperative hypotension, myocardial ischaemia and haemodynamic collapse.

1. Aortic stenosis

Symptomatic severe aortic stenosis creates substantial risk of perioperative hypotension, myocardial ischaemia and haemodynamic collapse. Contemporary ACC/AHA guidance recommends assessing severe AS for valve intervention before elective noncardiac surgery, especially elevated-risk procedures. The decision should involve cardiology, anaesthesia and surgery.

2. Preoperative risk

Applied anatomy and pathology

The diaphragmatic surface is formed predominantly by the left ventricle with a substantial right ventricular contribution (classically about two-thirds left and one-third right). It rests on the central tendon of the diaphragm.
The right coronary artery originates from the right coronary sinus of Valsalva, often termed the anterior aortic sinus. It travels in the right atrioventricular groove and usually gives a right marginal branch.
Coronary dominance depends on origin of the posterior descending artery.

Clinical recognition and differential diagnosis

Distinguish wild-type from hereditary transthyretin amyloidosis.
Syncope, angina and dyspnoea are classic symptomatic features.

Investigations and diagnostic interpretation

Increased ventricular wall thickness with relatively low ECG voltage is a classic clue.

Management and operative principles

Asymptomatic severe AS undergoing low-risk surgery may be handled differently after evaluation.

Measurements, staging and thresholds

Severe AS may be defined by valve area ≤1.0 cm², Vmax ≥4 m/s or mean gradient ≥40 mmHg, with low-flow exceptions.

Common examiner traps

Do not extrapolate this recommendation to every asymptomatic patient with moderate AS undergoing minor surgery.
Autoregulation is not unlimited; severe hypotension and critical stenosis make flow pressure-dependent.
Do not confuse the anterior sternocostal surface (mostly RV) with the inferior diaphragmatic surface.
Never assume ATTR without evaluating for AL amyloidosis, which requires different urgent treatment.
Do not equate desmosomal mechanical adhesion with gap-junction ion conductance.

Rapid-recall exam pearls

Symptomatic severe AS before elective major surgery: evaluate for valve intervention first.
Older man + restrictive HF + low-voltage ECG despite thick walls = consider ATTR amyloid.
Lower perfusion pressure with maintained flow requires lower arteriolar resistance.
Cardiac gap junctions = electrical coupling; desmosomes = mechanical strength.
Right coronary artery originates in the right/anterior aortic sinus.

Lung disease and thoracic malignancy

Overview. Thoracic symptoms may reflect infection, obstruction, neoplasia or cardiopulmonary disease; imaging and tissue diagnosis establish the anatomical cause.

Topic map — key distinctions

Subtopic	Defining feature / key principle
Lung cancer and paraneoplasia	Small-cell lung carcinoma can ectopically secrete ADH, causing SIADH with hypotonic hyponatraemia and urine that is not maximally dilute.
Pleural conditions	Malignant pleural mesothelioma arises from the pleural mesothelium and is strongly associated with past asbestos exposure.
Staging and investigations	For symptomatic malignant central airway obstruction, CHEST recommends therapeutic bronchoscopy as an adjunct to oncological therapy, with rigid bronchoscopy preferred for therapeutic interventions when feasible.
Surgical or emergency treatment	Absence of invasion must be established on an adequately sampled resection specimen.

1. Lung cancer and paraneoplasia

Small-cell lung carcinoma can ectopically secrete ADH, causing SIADH with hypotonic hyponatraemia and urine that is not maximally dilute. The biochemical diagnosis requires exclusion of adrenal, thyroid and other relevant causes.

Small-cell lung cancer is strongly associated with SIADH and ectopic ACTH.
Squamous lung cancer → PTHrP → hypercalcaemia; small-cell cancer → SIADH/ACTH.
Small-cell lung cancer + euvolaemic hyponatraemia = think SIADH.
Small-cell lung cancer + SIADH = classic paraneoplastic pair.
Squamous lung cancer → PTHrP; small-cell lung cancer → SIADH.
Small-cell lung carcinoma is a neuroendocrine tumour that can secrete ectopic ADH, causing SIADH with hypotonic hyponatraemia and inappropriately concentrated urine in a euvolaemic patient.

2. Pleural conditions

Malignant pleural mesothelioma arises from the pleural mesothelium and is strongly associated with past asbestos exposure. It often presents after a long latency with unilateral pleural thickening, recurrent effusion, dyspnoea and chest pain. Tissue diagnosis is required.

Pleural effusion classically produces stony dullness and reduced vocal resonance.
Adenocarcinoma in situ is a small (≤3 cm) solitary adenocarcinoma with pure lepidic growth and no stromal, vascular or pleural invasion, necrosis or spread through air spaces. Ground-glass CT appearance is suggestive but cannot establish the diagnosis without complete pathological assessment. A 6-mm invasive component exceeds the minimally invasive threshold.
Asbestos exposure is also associated with lung carcinoma and benign pleural plaques.
Contrast CT helps define pleural extent; thoracoscopic biopsy may provide diagnosis.
Definitive treatment is pleural drainage after immediate decompression as indicated.
Emergency pleural decompression, then definitive chest drainage.

3. Staging and investigations

For symptomatic malignant central airway obstruction, CHEST recommends therapeutic bronchoscopy as an adjunct to oncological therapy, with rigid bronchoscopy preferred for therapeutic interventions when feasible. Debulking and selective stenting can rapidly restore airway patency; staging and definitive oncological care follow stabilisation.

PET-CT helps detect metabolically active nodal/distant disease but may require tissue confirmation.
Rigid bronchoscopy permits mechanical debulking, large-bore suction and stent placement.
CT chest with contrast maps local tumour anatomy; PET-CT and EBUS complete staging.
Contrast-enhanced CT establishes the primary lung tumour’s size, relation to bronchi and major vessels, and apparent invasion of adjacent structures. PET-CT and EBUS/EUS sampling complement CT for nodal and distant staging before definitive treatment.
CT-guided percutaneous biopsy directly targets a peripheral pulmonary mass that is not accessible endobronchially. Bronchoscopic navigation or surgical biopsy may be preferable in selected cases depending on lesion location, pneumothorax risk, local expertise and whether other sites can be sampled more safely.
Epithelioid histiocytes are activated macrophages that aggregate to form granulomas. A caseating granuloma with upper-lobe cavitation strongly raises the possibility of pulmonary tuberculosis, although tissue or microbiological confirmation is required.

4. Surgical or emergency treatment

Absence of invasion must be established on an adequately sampled resection specimen.

Lung AIS = ≤3 cm, pure lepidic growth, no invasion on resection.

Applied anatomy and pathology

Supraclavicular lymphadenopathy in a patient with disseminated thoracic lesions is concerning for metastatic malignancy. Cytological atypia, mitoses and epithelial immunophenotyping can establish carcinoma and help direct the search for a primary site.
Squamous-cell lung carcinoma may secrete PTH-related peptide, producing humoral hypercalcaemia of malignancy with suppressed endogenous PTH. Hypercalcaemia impairs urinary concentrating ability, explaining thirst and polyuria; constipation, confusion and dehydration may coexist.
Squamous cell carcinoma of the lung is a classic cause of humoral hypercalcaemia of malignancy through PTH-related peptide (PTHrP), which increases bone resorption and renal calcium retention. Endogenous PTH is suppressed.

Clinical recognition and differential diagnosis

Severe acute unilateral loss of breath sounds with circulatory compromise is compatible with pneumothorax producing tension physiology. Intrathoracic pressure impairs venous return and cardiac output, making this a clinical emergency.
Keratin pearls and intercellular bridges indicate squamous differentiation. Pulmonary squamous-cell carcinoma is classically associated with smoking and central/hilar bronchial masses.
Gland formation or mucin production is characteristic of pulmonary adenocarcinoma, which commonly arises peripherally and is the most frequent lung cancer subtype among never-smokers.

Investigations and diagnostic interpretation

Reactivation pulmonary tuberculosis classically involves oxygen-rich upper lobes, can cause cavitation and constitutional symptoms, and may produce AFB-positive sputum. Mycobacterial NAAT and culture establish organism identification and susceptibility.
Pulmonary hamartomas are benign tumours containing disorganised but mature components such as cartilage, fat and fibrous tissue. Macroscopic fat and popcorn calcification on CT strongly support the diagnosis.
Cardiac echo assesses ventricular function; lung ultrasound detects diffuse B-lines but cannot alone determine aetiology.
If tension pneumothorax is clinically suspected in an unstable patient, decompress without waiting for imaging.

Management and operative principles

The right ventricle forms most of the anterior (sternocostal) surface of the heart and is vulnerable to blunt anterior thoracic trauma. Traumatic haemopericardium may cause tamponade, requiring immediate trauma and cardiac surgical assessment.
Persistent focal opacity after treatment requires follow-up and evaluation for an obstructing tumour when clinically indicated.
Treat severe symptomatic hypercalcaemia urgently while investigating the underlying malignancy.
To maintain ductal patency and systemic perfusion before definitive repair.

Measurements, staging and thresholds

Peripheral chemoreceptors, especially the carotid bodies at the common carotid bifurcations, rapidly increase ventilatory drive in hypoxaemia. The response becomes marked when PaO2 falls below roughly 60 mmHg. Central medullary chemoreceptors mainly detect CO2 via cerebrospinal-fluid/brain extracellular hydrogen ions.
MRI provides superior soft-tissue contrast for assessing brachial plexus, neural foramina, vertebral and vessel involvement in superior sulcus (Pancoast) tumours. These relationships affect local T category, resectability and planning; systemic staging is also required.
Lung adenocarcinoma is the commonest primary lung cancer in never-smokers and usually arises in a peripheral location. Imaging alone does not establish histology; tissue sampling and staging are required.
Biopsy choice should account for stage, accessible metastases, lung function and molecular testing needs.

Common examiner traps

Polyuria alone does not diagnose hypercalcaemia; biochemical calcium and PTH results were added to repair the vague source recall.
Anterior location makes the right ventricle vulnerable, but no single chamber is guaranteed to be injured in a given trauma.
PDA is usually a left-to-right shunt, but Eisenmenger physiology can reverse flow in advanced pulmonary hypertension.
High CVP does not automatically mean the patient is adequately resuscitated or that more diuresis is always safe.
Do not choose the biopsy route from tumour histology alone; target accessibility and staging strategy matter.

Rapid-recall exam pearls

Peripheral mass without endobronchial access: CT-guided percutaneous biopsy is a direct sampling option.
Isolated infantile juxtaductal coarctation: left posterolateral thoracotomy is the classic approach.
Unstable suspected tension pneumothorax is a clinical diagnosis requiring immediate decompression.
Hypoxia drives peripheral carotid chemoreceptors; CO2 primarily drives central chemoreceptors.
Dull percussion plus bronchial breath sounds plus increased vocal resonance = consolidation.

Respiratory and thoracic conditions

Overview. Assess acute respiratory symptoms by oxygenation, ventilation, pleural pathology and airway patency; management is dictated by immediate physiological threat.

Topic map — key distinctions

Subtopic	Defining feature / key principle
Oxygen and ventilation	Acidaemia with low bicarbonate indicates metabolic acidosis, while a raised PaCO2 indicates simultaneous respiratory acidosis.
Respiratory tests	Lactate, electrolytes/anion gap, oxygenation, serial ABGs and assessment of ventilation and perfusion.

1. Oxygen and ventilation

Acidaemia with low bicarbonate indicates metabolic acidosis, while a raised PaCO2 indicates simultaneous respiratory acidosis. For bicarbonate 17 mmol/L, Winter formula predicts PaCO2 about 33.5 ± 2 mmHg (4.5 kPa), far below the observed 54 mmHg. Thus ventilation is inadequate in addition to the metabolic acid load from shock, such as lactic acidosis.

Chronic alveolar hypoventilation causes carbon dioxide retention and respiratory acidosis. Over several days, the kidneys increase bicarbonate reabsorption and net acid excretion, raising serum bicarbonate and partially normalising pH.
Lactate, electrolytes/anion gap, oxygenation, serial ABGs and assessment of ventilation and perfusion.
Assess oxygenation, airway patency and tube position urgently in postoperative respiratory compromise.
Respiratory failure or hypoventilation can coexist with metabolic acidosis.
Sedative drugs can blunt ventilatory responses and precipitate hypercapnia.

2. Respiratory tests

Lactate, electrolytes/anion gap, oxygenation, serial ABGs and assessment of ventilation and perfusion.

Applied anatomy and pathology

The traditional safe triangle lies between the lateral border of pectoralis major anteriorly and anterior border of latissimus dorsi posteriorly, with an apex beneath the axilla and an inferior boundary near the fifth intercostal space.
Central location and cavitation favour squamous-cell carcinoma but are not diagnostic alone.
Keratin pearls and intercellular bridges indicate squamous differentiation.

Clinical recognition and differential diagnosis

Squamous-cell carcinoma of the lung is strongly associated with smoking, often arises centrally and may cavitate. Keratinisation and intercellular bridges are characteristic squamous differentiation. Histology is more decisive than location or cavitation alone.
A superior sulcus (Pancoast) tumour may invade the lower brachial plexus, producing pain, weakness and paraesthesia in C8–T1 distributions. Sympathetic chain involvement can cause ipsilateral Horner syndrome.
Radiographic volume-loss signs include hilar displacement, elevated hemidiaphragm and mediastinal shift toward collapse.

Investigations and diagnostic interpretation

Carbon dioxide crosses the blood–brain barrier readily and is hydrated to carbonic acid, increasing hydrogen ions in brain extracellular fluid/CSF. Medullary central chemoreceptors respond to the resulting fall in pH and normally drive increased ventilation.
Common insertion level is around the fourth or fifth intercostal space, guided by indication and imaging.
Diagnostic work-up may include nasal nitric oxide and specialised ciliary testing.
Assess volume status and exclude adrenal insufficiency and severe hypothyroidism.

Management and operative principles

Use blunt dissection and local safety checks for an appropriate surgical drain.

Measurements, staging and thresholds

Low bicarbonate indicates a metabolic acidosis. PaCO₂ is elevated rather than appropriately reduced. Winter’s formula predicts PaCO₂ approximately 1.5 × 17 + 8 = 33.5 mmHg (about 4.5 kPa), so the actual 54 mmHg proves an additional respiratory acidosis.
Tissue confirmation and staging guide definitive lung-cancer management.
Convert 7.2 kPa PaCO₂ to approximately 54 mmHg.

Common examiner traps

An isolated postoperative opacity is not diagnostic; the original recall lacked the added volume-loss signs.
Do not call any low pH with low bicarbonate compensated metabolic acidosis without checking expected PaCO₂.
Cavitation can also occur with infection or other tumours; use histology rather than the radiograph alone.
The fifth intercostal-space line is a lower boundary, not permission to insert blindly below it.
Do not confuse parasympathetic detrusor contraction with sympathetic urine storage.

Rapid-recall exam pearls

Central CO2 drive is mediated mainly through CSF hydrogen ions, not direct oxygen sensing.
Keratin pearls plus a cavitating smoker-associated lung mass = squamous-cell carcinoma.
Safe triangle: pectoralis major anterior, latissimus dorsi posterior, axilla superior.
Fight-or-flight physiology produces bronchodilatation, mydriasis and tachycardia.
Opaque lung plus mediastinal shift toward the opacity = volume loss/atelectasis.

Endocrine

Adrenal and catecholamine disorders

Overview. Adrenal disease is differentiated by cortisol, aldosterone and catecholamine excess or deficiency; hormonal control is essential before some operations.

Topic map — key distinctions

Subtopic	Defining feature / key principle
Adrenal insufficiency and crisis	Pituitary ACTH overproduction chronically stimulates the adrenal cortex, causing bilateral cortical hyperplasia and excess cortisol synthesis.
Phaeochromocytoma	Plasma free metanephrines or urinary fractionated metanephrines are preferred first-line biochemical tests for phaeochromocytoma/paraganglioma.
Adrenal venous anatomy	The left suprarenal vein typically drains into the left renal vein, often joining the left inferior phrenic vein before its entry.

1. Adrenal insufficiency and crisis

Pituitary ACTH overproduction chronically stimulates the adrenal cortex, causing bilateral cortical hyperplasia and excess cortisol synthesis. The primary lesion is pituitary, not a unilateral adrenal cortisol-secreting tumour.

2. Phaeochromocytoma

Plasma free metanephrines or urinary fractionated metanephrines are preferred first-line biochemical tests for phaeochromocytoma/paraganglioma. Plasma measurements should ideally be collected after quiet supine rest, with position-matched reference intervals, because upright posture and sympathetic activation can elevate normetanephrine and produce false positives. Medications, illness and analytical factors also affect interpretation.

Phaeochromocytoma: metanephrines; alpha blockade before beta blockade.
Catecholamine-secreting chromaffin tumours produce metanephrines continuously, making plasma free or urinary fractionated metanephrines preferred sensitive biochemical tests. Imaging follows biochemical assessment unless an emergency dictates otherwise.
Alpha-blockade is established first to control catecholamine-induced vasoconstriction and permit volume expansion. Beta-blockade can then be added for persistent tachycardia after adequate alpha-blockade.
Phaeochromocytoma: alpha first, beta second.
Phaeochromocytoma requires appropriate preoperative adrenergic preparation.

3. Adrenal venous anatomy

The left suprarenal vein typically drains into the left renal vein, often joining the left inferior phrenic vein before its entry. The right adrenal vein is short and drains directly into the inferior vena cava. This asymmetry is important during adrenalectomy.

Right adrenal vein → IVC; left adrenal vein → left renal vein.
The left adrenal vein commonly joins the left renal vein.
Left adrenal vein joins the left renal vein; right adrenal vein joins the IVC.
The right adrenal gland lies close to the inferior vena cava; its short right adrenal vein drains directly into the IVC. This is a crucial operative hazard during right adrenalectomy.
The right adrenal vein is shorter and its direct IVC entry is a major surgical hazard.

Applied anatomy and pathology

ARBs block the AT1 receptor; ACE inhibitors block conversion of angiotensin I to II.
Early identification of the short right adrenal vein helps avoid major haemorrhage.

Investigations and diagnostic interpretation

Preferred screening tests: plasma free or urinary fractionated metanephrines.
A positive test needs contextual interpretation and follow-up.

Management and operative principles

Alpha blockade precedes beta blockade when preparing a functional tumour for surgery.

Common examiner traps

Do not confuse the adrenal venous pattern with left and right gonadal veins, although both have a left renal vein connection.
Do not assume hyperkalaemia plus hyponatraemia proves an ARB adverse effect; consider adrenal and renal pathology.
Do not confuse the right adrenal gland’s relationship with the left-sided venous drainage pattern.
Unopposed alpha stimulation after beta-blockade can precipitate hypertensive crisis.
Old recalls favour urinary VMA, but modern metanephrine testing is more sensitive.

Rapid-recall exam pearls

ARB → less aldosterone effect → less distal potassium secretion → hyperkalaemia risk.
Supine sampling is a test-quality issue in plasma metanephrine interpretation.
Left adrenal vein joins the left renal vein; right adrenal vein joins the IVC.
Phaeochromocytoma: metanephrines; alpha blockade before beta blockade.
Pituitary ACTH excess -> bilateral adrenal cortical hyperplasia.

Diabetes, insulin and metabolic physiology

Overview. Insulin drives nutrient storage and transcellular potassium movement; perioperative metabolic complications demand rapid recognition and monitoring.

Topic map — key distinctions

Subtopic	Defining feature / key principle
Insulin and glucose	Insulin promotes GLUT4 translocation in skeletal muscle and adipose tissue, increasing cellular glucose uptake.
Potassium and electrolytes	Reintroduction of carbohydrate stimulates insulin release and cellular uptake of phosphate, potassium and magnesium in a profoundly depleted patient.

1. Insulin and glucose

Insulin promotes GLUT4 translocation in skeletal muscle and adipose tissue, increasing cellular glucose uptake. In muscle it activates glycogen synthase and favours glycogen storage. It also drives potassium into cells by stimulating Na+/K+-ATPase, which is clinically important during IV insulin administration.

Insulinoma secretes insulin inappropriately during hypoglycaemia. Whipple triad is symptoms compatible with hypoglycaemia, documented low plasma glucose and relief on correction.
Insulin promotes glycogen synthesis and inhibits hepatic glucose output.
Monitor glucose and potassium during IV insulin treatment.
Fasting neuroglycopenic attacks relieved by glucose = insulinoma until excluded.
Reintroduction of carbohydrate stimulates insulin release and cellular uptake of phosphate, potassium and magnesium in a profoundly depleted patient. Severe hypophosphataemia can cause diaphragmatic weakness, cardiac dysfunction and arrhythmias. NICE classifies BMI below 14 kg/m² as an extreme-risk example, warranting very cautious energy initiation and close monitoring.

2. Potassium and electrolytes

Reintroduction of carbohydrate stimulates insulin release and cellular uptake of phosphate, potassium and magnesium in a profoundly depleted patient. Severe hypophosphataemia can cause diaphragmatic weakness, cardiac dysfunction and arrhythmias. NICE classifies BMI below 14 kg/m² as an extreme-risk example, warranting very cautious energy initiation and close monitoring.

Insulin stimulates Na+/K+-ATPase in skeletal muscle and other tissues, rapidly redistributing potassium from extracellular fluid into cells. The effect is temporary and does not remove potassium from the body.
Definitive potassium removal may require diuretics, binders or dialysis according to context.
Check phosphate, potassium and magnesium before and during nutritional rehabilitation.
Monitor glucose and potassium during IV insulin treatment.
The hallmark of refeeding syndrome is a rapid fall in phosphate, often accompanied by low potassium and magnesium.

Applied anatomy and pathology

Muscle and adipose glucose uptake is GLUT4 dependent.

Clinical recognition and differential diagnosis

Symptoms, low glucose and symptom relief after glucose.

Investigations and diagnostic interpretation

ECG changes or severe hyperkalaemia may require IV calcium for cardiac membrane stabilisation.
Measure insulin, C-peptide, proinsulin and sulfonylurea screen during hypoglycaemia.
Assess insulin, C-peptide and proinsulin during hypoglycaemia.
Biochemical confirmation should precede localisation imaging.

Management and operative principles

Give thiamine before and during feeding and replace depleted electrolytes according to local protocols.

Common examiner traps

Do not use response to a short enzyme trial alone as a reliable diagnostic test for exocrine insufficiency.
Do not interpret a normal prefeeding serum phosphate as proof of normal total-body phosphate stores.
Do not mistake ECG stabilisation with IV calcium for serum-potassium reduction.
Insulin lowers serum potassium by intracellular shift, not urinary excretion.
Do not diagnose solely from symptoms without documenting plasma glucose.

Rapid-recall exam pearls

The hallmark of refeeding syndrome is a rapid fall in phosphate, often accompanied by low potassium and magnesium.
Fasting neuroglycopenic attacks relieved by glucose = insulinoma until excluded.
High insulin + high C-peptide during hypoglycaemia = endogenous hyperinsulinism.
Chronic pancreatitis + steatorrhoea + low faecal elastase = PERT with meals.
Insulin increases skeletal muscle GLUT4 activity and glycogen synthesis.

Endocrine glands, calcium and metabolic disorders

Overview. Endocrine pathology may produce multisystem clinical clues; localisation must follow biochemical diagnosis rather than precede it.

Topic map — key distinctions

Subtopic	Defining feature / key principle
Calcium physiology	Familial hypocalciuric hypercalcaemia (FHH) typically causes lifelong mild hypercalcaemia with relative hypocalciuria.
Thyroglossal duct cyst and surgery	Ultrasound is the preferred first-line investigation for a suspected thyroglossal duct cyst.
Parathyroid embryology	The dorsal part of the third pharyngeal pouch forms the inferior parathyroids and the ventral part forms the thymus.
Carcinoid syndrome	Serotonin is metabolised to 5-HIAA and excreted in urine.
Hypercalcaemia and metabolic physiology	Familial hypocalciuric hypercalcaemia (FHH) typically causes lifelong mild hypercalcaemia with relative hypocalciuria.

1. Calcium physiology

Familial hypocalciuric hypercalcaemia (FHH) typically causes lifelong mild hypercalcaemia with relative hypocalciuria. A low urinary calcium-to-creatinine clearance ratio, classically below 0.01, favours FHH, although overlap exists with primary hyperparathyroidism. Family history, vitamin D status, renal function and sometimes genetic testing are needed for interpretation.

PTH-dependent hypercalcaemia with familial lifelong history: check urinary calcium before considering parathyroid surgery.
Vitamin-D deficiency, CKD and thiazides can lower urinary calcium and confound interpretation.
FHH is often caused by inactivating variants affecting the calcium-sensing receptor pathway.
Check ionised or albumin-adjusted calcium and magnesium when tetany is suspected.
Reduced extracellular ionised calcium lowers the neuronal depolarisation threshold and increases neuromuscular excitability.
Calcium above about 3.5 mmol/L with symptoms is potentially life-threatening.

2. Thyroglossal duct cyst and surgery

Ultrasound is the preferred first-line investigation for a suspected thyroglossal duct cyst. It characterises the cyst and demonstrates a normally situated thyroid gland, helping identify rare cases in which ectopic thyroid tissue may be the only functioning tissue. The definitive Sistrunk operation includes the cyst, tract and central hyoid segment when indicated.

Thyroglossal duct remnants often traverse or closely relate to the hyoid. The Sistrunk procedure removes the cyst, its tract and the central portion of the hyoid bone, reducing recurrence compared with simple cyst excision.
A persistent embryological thyroglossal duct remnant forms a midline cyst connected to the tongue-base/hyoid region. Characteristic upward movement with tongue protrusion and swallowing helps distinguish it from other neck masses.
Definitive operation is the Sistrunk procedure including the central hyoid segment.
Sistrunk = cyst + duct tract + central hyoid.
A thyroglossal duct cyst commonly moves with tongue protrusion and swallowing.
A thyroglossal cyst typically moves with tongue protrusion.

3. Parathyroid embryology

The dorsal part of the third pharyngeal pouch forms the inferior parathyroids and the ventral part forms the thymus. Their common descent explains ectopic inferior parathyroid tissue in or near the thymus.

Third pouch = inferior parathyroids + thymus.

4. Carcinoid syndrome

Serotonin is metabolised to 5-HIAA and excreted in urine. A properly collected 24-hour urinary 5-HIAA supports serotonin-secreting carcinoid syndrome, especially with flushing and secretory diarrhoea. Testing does not replace tumour staging or histopathology.

Carcinoid syndrome often becomes clinically evident with hepatic metastases.

5. Hypercalcaemia and metabolic physiology

Severe symptomatic hypercalcaemia is an emergency. Restore intravascular volume with intravenous isotonic saline, assess ECG and renal function, identify the cause, and then use appropriate calcium-lowering agents (often an IV bisphosphonate or denosumab, with calcitonin for rapid short-term effect when needed). Fluids must be individualised in cardiac or renal failure.
FHH is often caused by inactivating variants affecting the calcium-sensing receptor pathway.
Parathyroidectomy usually does not correct FHH-associated hypercalcaemia.
PTH-dependent hypercalcaemia with familial lifelong history: check urinary calcium before considering parathyroid surgery.
Hypercalcaemic crisis: volume resuscitation and monitoring precede slower calcium-lowering therapy.
Do not use a single low urinary-calcium ratio as proof of FHH without checking confounders and clinical context.

Applied anatomy and pathology

Mineralocorticoid receptor activation from excess cortisol can occur despite suppressed aldosterone.
Cyst, duct tract and central portion of the hyoid, with a suprahyoid core as appropriate.
To reduce recurrence from residual duct tissue.

Clinical recognition and differential diagnosis

Pemberton sign is elicited by arm elevation in patients with thoracic-inlet or superior mediastinal venous compression, classically from a retrosternal goitre. Raising the arms further crowds the thoracic inlet, causing facial congestion, venous distension and sometimes stridor or dyspnoea.
The mass may compress or deviate the trachea at the thoracic inlet; chronic compression may coexist with tracheomalacia.
Trousseau sign is more specific for latent tetany than Chvostek sign but is not pathognomonic for hypocalcaemia.

Investigations and diagnostic interpretation

An impalpable inferior thyroid border suggests extension below the thoracic inlet. Retrosternal goitres can displace or compress the trachea, and cross-sectional imaging helps define intrathoracic extent and operative anatomy.
CT neck/chest helps delineate retrosternal extension and airway compression when indicated.
Measure glucose, insulin, C-peptide, proinsulin and sulfonylurea screen during an episode.
Assess volume status, ECG, electrolytes, creatinine, PTH and medication history.

Management and operative principles

Primary adrenal failure causes cortisol and aldosterone deficiency, leading to shock, hyponatraemia and hyperkalaemia. Suspected adrenal crisis is a time-critical emergency: give parenteral hydrocortisone promptly, restore circulating volume with 0.9% saline and treat precipitating illness.
Biochemical confirmation and localisation are required; urgent endocrine input is important.
Treat suspected adrenal crisis immediately; do not await confirmatory endocrine tests.
Treat acute infection before elective Sistrunk surgery when feasible.

Measurements, staging and thresholds

Hydrocortisone 100 mg IV/IM immediately with prompt 0.9% saline resuscitation, followed by stress-dose hydrocortisone and monitoring.
Hydrocortisone 100 mg IV/IM immediately, then 200 mg over 24 hours or 50 mg every six hours with fluids.
Trousseau sign: suprasystolic cuff inflation for about 2–3 minutes causes carpopedal spasm.
A large appendiceal neuroendocrine tumour needs oncological staging and operative review.

Common examiner traps

Do not give thyroid hormone to an unrecognised cortisol-deficient patient without addressing adrenal insufficiency; it can precipitate crisis.
Not every impalpable lower border proves retrosternal extension; obesity and neck anatomy may limit examination.
Do not use a single low urinary-calcium ratio as proof of FHH without checking confounders and clinical context.
Do not confuse Pemberton sign with Trousseau sign: both are provocative but test entirely different physiology.
Hyponatraemia with hyperkalaemia suggests mineralocorticoid deficiency, unlike most secondary adrenal failure.

Rapid-recall exam pearls

PTH-dependent hypercalcaemia with familial lifelong history: check urinary calcium before considering parathyroid surgery.
High insulin plus high C-peptide during hypoglycaemia indicates endogenous secretion, but exclude sulfonylureas.
Hypercalcaemic crisis: volume resuscitation and monitoring precede slower calcium-lowering therapy.
Hyperpigmentation plus hyperkalaemia points to primary rather than secondary adrenal insufficiency.
Small-cell lung cancer + ACTH excess + hypokalaemic alkalosis = consider ectopic ACTH syndrome.

Parathyroid and calcium disorders

Overview. Hyperparathyroidism produces abnormal calcium–PTH coupling; distinguish primary gland disease from renal and vitamin-D-related secondary change.

Topic map — key distinctions

Subtopic	Defining feature / key principle
Primary hyperparathyroidism	Autonomous secretion from a single benign parathyroid adenoma accounts for most primary hyperparathyroidism.
Secondary/tertiary disease	After prolonged secondary hyperparathyroidism in advanced CKD, parathyroid hyperplasia can become autonomous, producing tertiary hyperparathyroidism with markedly elevated PTH and hypercalcaemia.
Calcium crisis	Hypercalcaemia with an inappropriately raised PTH indicates PTH-dependent hypercalcaemia.
Localisation and operative strategy	Technetium-99m sestamibi scintigraphy is an established method of parathyroid adenoma localisation.

1. Primary hyperparathyroidism

Autonomous secretion from a single benign parathyroid adenoma accounts for most primary hyperparathyroidism. Increased PTH raises serum calcium through bone resorption, renal calcium handling and vitamin-D activation, predisposing to nephrolithiasis.

Technetium-99m sestamibi scintigraphy is an established method of parathyroid adenoma localisation. It is a preoperative localisation tool, not the diagnostic test for primary hyperparathyroidism; ultrasound is commonly the first imaging modality.
Hypercalcaemia with an inappropriately raised PTH indicates PTH-dependent hypercalcaemia. Primary hyperparathyroidism can produce renal calculi, gastrointestinal symptoms and neuropsychiatric features. Confirm the biochemical pattern, assess renal function, vitamin D and urinary calcium, and consider definitive parathyroidectomy according to indications.
Primary hyperparathyroidism plus gastrinoma suggests MEN1. Gastrin excess stimulates gastric acid secretion, causing recurrent ulcers and sometimes diarrhoea due to acid-mediated inactivation of pancreatic enzymes and mucosal injury.
Primary hyperparathyroidism is commonly the earliest and most frequent manifestation.
Diagnose primary hyperparathyroidism biochemically with calcium and PTH.
MEN1 commonly presents with multigland primary hyperparathyroidism.

2. Secondary/tertiary disease

After prolonged secondary hyperparathyroidism in advanced CKD, parathyroid hyperplasia can become autonomous, producing tertiary hyperparathyroidism with markedly elevated PTH and hypercalcaemia. Phosphate can remain elevated in dialysis-dependent patients because impaired renal excretion persists despite PTH action.

Tertiary disease has autonomous gland function and hypercalcaemia after chronic secondary stimulation.
Tertiary hyperparathyroidism is autonomous PTH secretion after longstanding secondary disease.
Tertiary hyperparathyroidism implies autonomous secretion after prolonged secondary disease.
High calcium alone does not distinguish primary from tertiary disease; renal history and prolonged secondary hyperparathyroidism matter.
Do not confuse secondary CKD hyperparathyroidism with tertiary disease, where autonomous secretion often produces hypercalcaemia.
Secondary and tertiary hyperparathyroidism are distinguished partly by autonomy and calcium status.

3. Calcium crisis

Hypercalcaemia with an inappropriately raised PTH indicates PTH-dependent hypercalcaemia. Primary hyperparathyroidism can produce renal calculi, gastrointestinal symptoms and neuropsychiatric features. Confirm the biochemical pattern, assess renal function, vitamin D and urinary calcium, and consider definitive parathyroidectomy according to indications.

Tertiary disease has autonomous gland function and hypercalcaemia after chronic secondary stimulation.
Bone pain, fractures and persistent hypercalcaemia may indicate clinically important disease.
Tertiary hyperparathyroidism typically causes persistent PTH elevation with hypercalcaemia.
The triad is hypercalcaemia, metabolic alkalosis and acute or chronic renal impairment.
Familial hypocalciuric hypercalcaemia is an important biochemical differential.
PTH is usually suppressed because hypercalcaemia is PTH-independent.

4. Localisation and operative strategy

Technetium-99m sestamibi scintigraphy is an established method of parathyroid adenoma localisation. It is a preoperative localisation tool, not the diagnostic test for primary hyperparathyroidism; ultrasound is commonly the first imaging modality.

Sestamibi or other second-line localisation can be used when useful; negative imaging does not exclude disease.
Sestamibi localises an adenoma; serum calcium/PTH establishes the diagnosis.
Do not present sestamibi as the first diagnostic test for hypercalcaemia.

Clinical recognition and differential diagnosis

MEN1 is an autosomal dominant syndrome due to pathogenic MEN1 variants. The characteristic organ triad is parathyroid, duodenopancreatic neuroendocrine system and anterior pituitary; pituitary lesions are often prolactinomas.
Sarcoidosis may present with Löfgren syndrome: erythema nodosum, bilateral hilar lymphadenopathy and arthritis.
Initial management includes stopping calcium/alkali and isotonic fluid repletion where clinically appropriate.

Investigations and diagnostic interpretation

Yes. Imaging can miss small or multigland disease; expert bilateral exploration may still be appropriate.
Localisation imaging is for operative planning, not for establishing a biochemical diagnosis.
The surgeon must communicate the precise intraoperative question to pathology.
Measure serum calcium and PTH together rather than interpreting either alone.

Management and operative principles

Fresh tissue is rapidly frozen, cut into thin sections in a cryostat and stained for immediate microscopic assessment, avoiding the time required for routine fixation and paraffin processing.

Measurements, staging and thresholds

Reduced phosphate excretion and reduced renal 1-alpha hydroxylation of vitamin D contribute to phosphate retention, lower calcium availability and compensatory PTH elevation. In CKD-MBD, PTH, calcium and phosphate must be interpreted as serial trends rather than a single threshold.
Correct modifiable factors such as high phosphate intake, vitamin D deficiency and hypocalcaemia according to CKD stage.

Common examiner traps

An isolated low TSH in a recall does not diagnose the cause of hypercalcaemia; biochemical calcium/PTH physiology and the antacid history are decisive.
High calcium alone does not distinguish primary from tertiary disease; renal history and prolonged secondary hyperparathyroidism matter.
Do not confuse secondary CKD hyperparathyroidism with tertiary disease, where autonomous secretion often produces hypercalcaemia.
Do not assume tertiary hyperparathyroidism always causes low phosphate; phosphate retention may persist in dialysis.
Do not confuse gastrinoma-associated diarrhoea with medullary thyroid carcinoma calcitonin diarrhoea.

Rapid-recall exam pearls

MEN1 = parathyroid + pancreatic/duodenal NET + pituitary; MEN2 = medullary thyroid carcinoma + phaeochromocytoma.
Long-standing CKD + very high PTH + new persistent hypercalcaemia = consider tertiary hyperparathyroidism.
High PTH + high phosphate + low/normal calcium in advanced CKD suggests secondary hyperparathyroidism.
Hypercalcaemia + suppressed PTH + hilar adenopathy suggests granulomatous vitamin-D activation.
Stones + hypercalcaemia + nonsuppressed PTH strongly suggest primary hyperparathyroidism.

Pituitary and endocrine genetics

Overview. Pituitary and inherited endocrine syndromes require recognition of hormone patterns and familial tumour associations.

Topic map — key distinctions

Subtopic	Defining feature / key principle
Pituitary axes	Exogenous T3 suppresses pituitary TSH by negative feedback.

1. Pituitary axes

Exogenous T3 suppresses pituitary TSH by negative feedback. With T3-only therapy, free T4 can be low because little or no T4 is administered. Serum T3 varies markedly with dose timing. Routine differentiated thyroid cancer replacement is generally levothyroxine-based rather than long-term T3 monotherapy.

Management and operative principles

Thyroglobulin, not calcitonin, is used for follow-up of differentiated thyroid carcinoma.

Common examiner traps

Do not assume T3-only therapy is standard long-term management after thyroid cancer.

Rapid-recall exam pearls

Exogenous T3: TSH down, T3 up, T4 often low on T3-only treatment.

Thyroid dysfunction and surgery

Overview. Always identify thyroid functional status before operative decisions; thyroidectomy risks relate to nearby laryngeal nerves and parathyroid vascular supply.

Topic map — key distinctions

Subtopic	Defining feature / key principle
Hyperthyroidism and storm	In overt primary hyperthyroidism, excess circulating thyroid hormone suppresses pituitary TSH through negative feedback.
Hypothyroidism and interpretation	Low free T4 with inappropriately low or normal TSH in pituitary disease indicates central hypothyroidism.
Thyroidectomy anatomy	The recurrent laryngeal nerve supplies all intrinsic laryngeal muscles except cricothyroid.
Postoperative complications	Postoperative parathyroid stunning, devascularisation or inadvertent removal can lower PTH and ionised calcium.
Preoperative optimisation	Thionamides inhibit thyroid hormone synthesis and should precede inorganic iodine in the conventional thyroid storm regimen.

1. Hyperthyroidism and storm

In overt primary hyperthyroidism, excess circulating thyroid hormone suppresses pituitary TSH through negative feedback. Elevated free T4 and/or T3 with suppressed TSH is the biochemical signature; a diffuse bruit supports hypervascular Graves disease.

Confirm true overt hyperthyroidism; transient gestational thyrotoxicosis may need no antithyroid drug.
Graves hyperthyroidism causes diffuse follicular epithelial hyperplasia, tall columnar cells, infoldings and colloid resorption giving a scalloped appearance. TSH-receptor-stimulating antibodies are the pathophysiological driver.
TRAb can cross the placenta and cause fetal or neonatal hyperthyroidism.
Treating hyperthyroidism often normalises calcium.
A low TSH does not always mean hyperthyroidism.
Low TSH plus high free T4/T3 = overt primary hyperthyroidism.

2. Hypothyroidism and interpretation

Low free T4 with inappropriately low or normal TSH in pituitary disease indicates central hypothyroidism. Concomitant ACTH deficiency must be assessed before thyroid replacement, because levothyroxine increases cortisol clearance and metabolic demand and can precipitate adrenal crisis. If adrenal insufficiency is possible and cannot promptly be excluded, give appropriate glucocorticoid cover before thyroid hormone.

Non-thyroidal illness can reduce circulating T3, and TSH may transiently rise during recovery. A mildly raised TSH with normal free T4 can also be subclinical hypothyroidism, but a single measurement in recent severe illness should be repeated after recovery before diagnosing a persistent disorder.
Autoimmune destruction of the thyroid gland reduces free T4 production; reduced negative feedback causes pituitary TSH to rise. The combination of high TSH and low free T4 establishes overt primary hypothyroidism in the appropriate context.
An elevated TSH with free T4 still within the laboratory reference range defines subclinical primary hypothyroidism. TSH should be repeated and anti-TPO antibodies considered; persistent TSH ≥10 mIU/L can justify considering levothyroxine.
Low free T4 with a low or inappropriately normal TSH suggests inadequate pituitary or hypothalamic stimulation. A sellar mass and other pituitary symptoms support central hypothyroidism.
Central hypothyroidism is diagnosed using free T4 with an inappropriately low/normal TSH.
A high TSH with normal free T4 may represent subclinical hypothyroidism if persistent.

3. Thyroidectomy anatomy

The recurrent laryngeal nerve supplies all intrinsic laryngeal muscles except cricothyroid. Unilateral injury causes vocal-fold paresis or paralysis with dysphonia and potentially aspiration.

The left recurrent laryngeal nerve loops beneath the aortic arch; the right beneath the subclavian artery.
Most other intrinsic laryngeal muscles receive recurrent laryngeal innervation.
Bilateral recurrent laryngeal nerve injury may threaten the airway.
Post-thyroidectomy breathy hoarseness + immobile cord = recurrent laryngeal nerve.

4. Postoperative complications

Postoperative parathyroid stunning, devascularisation or inadvertent removal can lower PTH and ionised calcium. Hypocalcaemia increases neuromuscular excitability, causing perioral paraesthesia, tetany and QT prolongation.

Also monitor voice changes and airway-threatening neck haematoma after thyroidectomy.
Symptomatic severe hypocalcaemia may require monitored intravenous calcium.
Severe symptomatic hypocalcaemia may require IV calcium under monitoring.
Severe symptomatic hypocalcaemia may require intravenous calcium.
Post-thyroidectomy tetany is hypocalcaemia until proved otherwise.
Low magnesium can cause refractory hypocalcaemia; do not treat calcium alone without assessing it.

5. Preoperative optimisation

Thionamides inhibit thyroid hormone synthesis and should precede inorganic iodine in the conventional thyroid storm regimen. Iodine given after the thionamide (typically at least an hour later) acutely suppresses hormone release while avoiding supplying substrate for additional hormone synthesis before blockade. Concurrent supportive care, beta-blockade when safe, glucocorticoids and treatment of the precipitant are essential.

Radioiodine can exacerbate Graves orbitopathy, especially in active or severe eye disease, and is generally contraindicated in active severe orbitopathy. For relapsed Graves disease, specialist discussion includes antithyroid medication and definitive surgery after achieving adequate preparation. Eye disease needs parallel ophthalmology/endocrine management.
After relapse following an adequate antithyroid-drug course, radioactive iodine or surgery are recognised definitive options. In a non-pregnant patient who prefers to avoid surgery and has no contraindication, radioiodine is appropriate; future hypothyroidism is expected and monitored.
Antithyroid therapy and beta-blockade may be needed before definitive treatment.
Thyroid storm: beta-blocker + thionamide → iodine + steroid + supportive care.
Relapsed Graves after antithyroid drugs: consider radioiodine or surgery.
Do not give iodine before thionamide; avoid reflex high-dose beta-blockade in unstable heart failure.

Applied anatomy and pathology

The external branch of the superior laryngeal nerve innervates the cricothyroid muscle, which tenses and lengthens the vocal folds to increase pitch. Injury can impair high notes and vocal projection, especially noticeable in singers and teachers.
The external superior laryngeal nerve is particularly vulnerable near superior thyroid vessels.
The external superior laryngeal nerve runs near the superior thyroid vascular pedicle.

Clinical recognition and differential diagnosis

Transient parathyroid devascularisation or inadvertent removal during thyroidectomy can lower PTH, reduce ionised calcium and cause neuromuscular hyperexcitability. Check ionised or corrected serum calcium, magnesium and PTH when clinically appropriate.
When antithyroid treatment is needed in the first trimester, PTU is generally preferred because methimazole/carbimazole exposure is associated with rare but important embryopathy. PTU carries a hepatotoxicity risk, so clinicians reassess therapy after the first trimester and aim for the lowest effective dose.
Propranolol or metoprolol can be used for troublesome symptoms when clinically appropriate during lactation.

Investigations and diagnostic interpretation

Technetium-99m sestamibi imaging, often with SPECT/CT, is a recognised preoperative localisation method, frequently complemented by expert cervical ultrasound. Imaging is performed to guide surgery after biochemical diagnosis, not to diagnose hyperparathyroidism.
Unintentional removal, bruising or devascularisation of parathyroids during thyroidectomy may impair PTH secretion, lowering ionised calcium. Tetany and paraesthesiae require prompt assessment of calcium, magnesium and ECG.
Request an urgent full blood count with neutrophil differential; a total WBC alone can be misleading.
Biochemical diagnosis is based on suppressed TSH with elevated thyroid hormones, not routine biopsy.

Management and operative principles

Thyroid storm is a life-threatening clinical syndrome requiring simultaneous supportive care, control of adrenergic manifestations, inhibition of thyroid hormone synthesis, inhibition of hormone release and glucocorticoid treatment. Iodine is conventionally given at least one hour after thionamide.
Beta blockers relieve symptoms in the thyrotoxic phase; antithyroid drugs do not treat hormone leakage.
Warn patients to stop the drug and seek urgent assessment for fever, sore throat or mouth ulcers.
Confirmed febrile neutropenia requires urgent sepsis evaluation and treatment.

Common examiner traps

Postpartum Graves disease requires different management; distinguish it from thyroiditis rather than treating every low TSH with carbimazole.
Anti-TPO supports the diagnosis but antibody positivity alone does not establish clinically significant hypothyroidism.
Never start thyroid hormone in suspected combined pituitary failure without addressing possible cortisol deficiency.
Papillary infoldings in Graves lack the true fibrovascular cores and nuclear features of papillary carcinoma.
Low uptake is a clue to hormone leakage, not increased synthesis; do not reflexively prescribe carbimazole.

Rapid-recall exam pearls

High free T4 + low TSH + mild hypercalcaemia + suppressed PTH can reflect thyroid-driven bone resorption.
Destructive postpartum thyrotoxicosis: beta blocker for symptoms; antithyroid drugs do not help.
Thyrotoxicosis followed by hypothyroidism + low uptake + painless gland = silent thyroiditis.
Graves disease in a breastfeeding mother can usually be treated with low-dose carbimazole.
Scalloped colloid with diffuse follicular hyperplasia is characteristic of Graves disease.

Thyroid nodules and carcinoma

Overview. A thyroid nodule is evaluated with ultrasound risk features, thyroid function and appropriately indicated fine-needle sampling; cancer management depends on histotype and stage.

Topic map — key distinctions

Subtopic	Defining feature / key principle
Nodule ultrasound and FNA	When TSH is suppressed in a patient with a thyroid nodule, radionuclide scintigraphy can identify a hyperfunctioning (“hot”) nodule.
Papillary and follicular cancers	Abundant colloid with bland follicular cells favours a benign colloid nodule.
Medullary carcinoma	Medullary thyroid carcinoma arises from parafollicular C cells, produces calcitonin and commonly contains extracellular amyloid derived from altered calcitonin-related peptides.
Anaplastic and lymphoma	Anaplastic thyroid carcinoma is a highly dedifferentiated malignancy that often loses the ability to synthesise thyroglobulin or concentrate radioiodine.
Neck management and follow-up	Thyroglobulin is produced by differentiated thyroid follicular cells and serves as a disease marker after total thyroidectomy, often with radioactive iodine according to risk.

1. Nodule ultrasound and FNA

When TSH is suppressed in a patient with a thyroid nodule, radionuclide scintigraphy can identify a hyperfunctioning (“hot”) nodule. Such nodules have a low malignancy probability and are usually not sampled by FNA solely because of size; clinical and ultrasound red flags still require individual assessment. Ultrasound and biochemical assessment remain essential components of the initial work-up.

High-resolution neck ultrasound is the initial imaging investigation for a clinically detected thyroid nodule. It characterises size, echogenicity, margins, microcalcifications and cervical nodes, informing risk stratification and whether ultrasound-guided FNAC is needed. Serum TSH should also be measured; scintigraphy is considered when TSH is low.
Ultrasound risk features guide FNAC decisions according to nodule size and local guidance.
Ultrasound-guided FNAC samples cells from a nodule that meets size and sonographic risk criteria and is the principal cytological investigation. Ultrasound and TSH guide the decision to sample; cytology is not indicated indiscriminately for every thyroid nodule.
For a suspicious euthyroid thyroid nodule, ultrasound-guided FNAC is the diagnostic tissue test.
Do not use FNAC as the automatic first test for every thyroid nodule; consider TSH and ultrasound risk stratification.
Suppressed TSH + nodule → consider scintigraphy before FNA.

2. Papillary and follicular cancers

Abundant colloid with bland follicular cells favours a benign colloid nodule. Papillary carcinoma requires characteristic nuclear features; medullary carcinoma arises from parafollicular C cells; Hashimoto thyroiditis shows lymphocytic inflammation and Hürthle-cell change.

Papillary thyroid carcinoma has a strong tendency to spread to regional cervical lymph nodes, sometimes despite a small primary tumour. Follicular carcinoma more often spreads haematogenously to bone and lung.
Follicular thyroid carcinoma classically invades blood vessels and spreads haematogenously to bone and lung. Papillary thyroid carcinoma more characteristically spreads via lymphatics to cervical nodes.
Papillary frequently spreads to cervical lymph nodes; follicular carcinoma more commonly spreads via blood to lung and bone.
Papillary and follicular cancers arise from thyroid follicular cells and are classed as differentiated carcinomas.
Differentiated papillary and follicular carcinomas of follicular-cell origin.
Follicular = haematogenous; papillary = lymphatic is a useful exam contrast, not an absolute rule.

3. Medullary carcinoma

Medullary thyroid carcinoma arises from parafollicular C cells, produces calcitonin and commonly contains extracellular amyloid derived from altered calcitonin-related peptides. Congo red-positive amyloid stroma is a classic histological clue. RET testing and screening for MEN2-associated phaeochromocytoma are important when clinically appropriate.

Calcitonin is a tumour marker secreted by medullary thyroid carcinoma C cells. Serial calcitonin and CEA doubling times are useful measures of tumour kinetics; a calcitonin doubling time shorter than six months is associated with more aggressive disease than a doubling time exceeding two years. Imaging and treatment depend on the complete clinical picture.
Medullary thyroid carcinoma arises from parafollicular C cells and usually secretes calcitonin; calcitonin and CEA are the standard markers used together to follow biochemical disease burden. CEA is the best answer from this source option set because calcitonin is absent.
Medullary thyroid carcinoma is a neuroendocrine malignancy of calcitonin-secreting parafollicular cells. Thyroid follicular function may remain normal, so a normal TSH and free T4 do not exclude it; marked calcitonin elevation is a major clue requiring specialist assessment.
Medullary thyroid carcinoma arises from parafollicular C cells and can secrete calcitonin and CEA. CEA assists postoperative surveillance, particularly when interpreted serially alongside calcitonin.
Medullary thyroid cancer: calcitonin, RET, total thyroidectomy, nodal assessment.
Medullary thyroid carcinoma arises from calcitonin-producing parafollicular C cells. With confirmed regional nodal spread and no prohibitive distant disease, standard management involves total thyroidectomy, central compartment clearance and therapeutic dissection of clinically involved lateral nodal levels.

4. Anaplastic and lymphoma

Anaplastic thyroid carcinoma is a highly dedifferentiated malignancy that often loses the ability to synthesise thyroglobulin or concentrate radioiodine. Therefore a normal serum thyroglobulin cannot exclude anaplastic recurrence. In contrast, thyroglobulin is an important surveillance marker in appropriately treated differentiated papillary and follicular carcinomas; calcitonin is characteristic of medullary carcinoma.

Do not mistake a rapidly growing thyroid lymphoma for anaplastic thyroid carcinoma without adequate tissue.
Anaplastic thyroid carcinoma is a highly aggressive undifferentiated thyroid malignancy, often in older adults, causing rapid local invasion and compressive airway symptoms. Urgent airway evaluation and multidisciplinary oncological management are essential.
Anaplastic thyroid cancer is aggressive and requires rapid specialist multidisciplinary evaluation.
Anaplastic carcinoma loses differentiated thyroid functions, including radioiodine uptake.
Elderly patient + rapidly enlarging thyroid mass + stridor = suspect anaplastic carcinoma.
Normal thyroglobulin does not exclude anaplastic thyroid carcinoma recurrence.

5. Neck management and follow-up

Thyroglobulin is produced by differentiated thyroid follicular cells and serves as a disease marker after total thyroidectomy, often with radioactive iodine according to risk. Interpretation requires checking thyroglobulin antibodies and residual thyroid tissue.

Medullary thyroid cancer originates from parafollicular C cells, and definitive treatment is total thyroidectomy with nodal surgery according to involved compartments. Before operating, screen for associated phaeochromocytoma and assess germline RET status.
Counsel about possible intraoperative conversion or later completion thyroidectomy if higher-risk pathology emerges.
Lobectomy has lower rates of hypocalcaemia and bilateral recurrent-laryngeal-nerve risk than total thyroidectomy.
Treatment is commonly haematological rather than routine thyroidectomy.
For tumours >4 cm, gross extrathyroidal extension or clinically involved nodes, total thyroidectomy is generally recommended.
For low-risk unilateral PTC >2 to 4 cm, lobectomy or total thyroidectomy may be considered after shared decision-making.

Applied anatomy and pathology

The distinction between follicular adenoma and carcinoma requires demonstration of capsular and/or vascular invasion in a histological specimen. Cytology can identify a follicular neoplasm but cannot evaluate the complete capsule.
Papillary thyroid carcinoma commonly demonstrates optically clear Orphan Annie-eye nuclei, grooves and intranuclear cytoplasmic pseudoinclusions, often with papillary architecture and psammoma bodies.
Papillary thyroid carcinoma classically shows nuclear clearing, grooves and pseudoinclusions, but frequency is a separate concept from histological identification.

Clinical recognition and differential diagnosis

Catecholamine-secreting adrenal medullary tumours produce paroxysmal headache, sweating and palpitations with severe or labile hypertension. In a patient with possible MEN2-related thyroid disease, phaeochromocytoma should be excluded and, if present, treated before thyroidectomy to avoid a catecholamine crisis.
Primary thyroid lymphoma is strongly associated with chronic autoimmune Hashimoto thyroiditis and is usually a B-cell non-Hodgkin lymphoma, commonly diffuse large B-cell or MALT type.
Therapeutic lateral dissection targets clinically involved compartments; not a radical neck dissection by default.

Investigations and diagnostic interpretation

Follicular thyroid carcinoma is defined by capsular and/or vascular invasion and commonly spreads through blood vessels to bone and lung. Cytology alone cannot reliably distinguish follicular adenoma from carcinoma because invasion must be assessed histologically.
Medullary thyroid carcinoma arises from parafollicular C cells and can spread to central cervical nodes even without imaging-detected disease. ATA guidance recommends total thyroidectomy with central-compartment dissection for MTC without detected nodal or distant metastases.
Preoperative dysphonia in suspected thyroid cancer mandates laryngeal examination to document vocal-fold mobility and possible recurrent laryngeal nerve involvement. Identifying pre-existing paralysis changes surgical planning and is essential when considering risk to the contralateral nerve.
Benign thyroid cytology in a clinically low-risk nodule generally supports observation. The ultrasound pattern guides follow-up frequency and whether repeat sampling is indicated for significant growth or new suspicious features.

Management and operative principles

Current ATA guidance discourages prophylactic central-compartment lymph node dissection for most small, non-invasive cT1–T2, cN0 papillary thyroid carcinomas. Therapeutic compartment dissection is indicated when nodes are structurally involved; unnecessary prophylactic surgery adds morbidity.
MEN2A, caused by germline activating RET variants, classically combines medullary thyroid carcinoma, phaeochromocytoma and primary hyperparathyroidism. Biochemical exclusion and management of phaeochromocytoma are essential before thyroid surgery.
RET-associated familial cases require MEN2 assessment; exclude phaeochromocytoma before thyroid surgery.
Dysphonia, prior neck surgery or extensive posterior tumour invasion are indications for laryngoscopy.

Measurements, staging and thresholds

Primary thyroid lymphoma is managed according to histological subtype and stage, usually with lymphoma-directed systemic treatment rather than gland excision.
Large tumours >4 cm, gross extrathyroidal extension, clinically apparent metastases or selected bilateral/high-risk features.
Treatment depends on lymphoma subtype and stage, often rituximab-containing therapy with or without radiotherapy.
When surgery is chosen for low-risk disease 2 cm or smaller, lobectomy is the preferred initial operation.

Common examiner traps

Do not assume that a patient with thyroid cancer has a normal recurrent laryngeal nerve simply because the voice sounds near normal.
Do not use FNAC as the automatic first test for every thyroid nodule; consider TSH and ultrasound risk stratification.
Do not turn an epidemiological answer into a diagnosis for an individual 30-year-old with an uncharacterised nodule.
Never initiate isolated beta blockade before adequate alpha blockade in a confirmed catecholamine-secreting tumour.
Do not assume every rapidly enlarging thyroid mass is anaplastic carcinoma; immunophenotyping changes treatment.

Rapid-recall exam pearls

Low-risk unilateral 3-cm PTC without nodes: lobectomy is a legitimate initial option, not an obligatory total thyroidectomy.
When an MRCS question explicitly asks the most prevalent thyroid carcinoma overall, choose papillary.
Follicular = haematogenous; papillary = lymphatic is a useful exam contrast, not an absolute rule.
Very high calcitonin with a thyroid nodule points toward MTC even if thyroid hormones are normal.
MTC with involved lateral nodes = total thyroidectomy plus compartment-oriented node dissection.

Gastrointestinal

Abdominal wall and hernia

Overview. Hernias are defined by anatomical site and fascial defect; examination establishes reducibility, obstruction and strangulation risk.

Topic map — key distinctions

Subtopic	Defining feature / key principle
Inguinal anatomy	TEP mesh occupies the extraperitoneal/preperitoneal plane; the parietal peritoneum is posterior to the mesh.
Femoral and other hernias	The femoral ring is bounded anteriorly by the inguinal ligament, posteriorly by the pectineal (Cooper) ligament, medially by the lacunar ligament and laterally by the femoral vein.
Complications and repair	The femoral ring is bounded anteriorly by the inguinal ligament, posteriorly by the pectineal (Cooper) ligament, medially by the lacunar ligament and laterally by the femoral vein.
Abdominal wall anatomy	The spermatic cord acquires the internal spermatic fascia from transversalis fascia as it passes through the deep inguinal ring.

1. Inguinal anatomy

TEP mesh occupies the extraperitoneal/preperitoneal plane; the parietal peritoneum is posterior to the mesh. The mesh reinforces direct, indirect and femoral potential defects within the myopectineal orifice.

Cover the entire myopectineal orifice including direct, indirect and femoral spaces.
Inferior epigastric vessels help distinguish direct from indirect defects.

2. Femoral and other hernias

The femoral ring is bounded anteriorly by the inguinal ligament, posteriorly by the pectineal (Cooper) ligament, medially by the lacunar ligament and laterally by the femoral vein. This confined neck explains the relatively high strangulation risk of femoral hernias.

The femoral ring is bounded anteriorly by the inguinal ligament, posteriorly by pectineal ligament/pectineus fascia, medially by the lacunar ligament and laterally by the femoral vein. The aberrant obturator artery (corona mortis) may be endangered during medial release.
The femoral nerve (L2–L4) supplies quadriceps femoris, the principal knee extensor. A femoral nerve block may cause temporary quadriceps weakness and falls risk, unlike the predominantly sensory nerves usually targeted for groin analgesia.
The femoral nerve (L2–L4) supplies quadriceps, producing knee extension; it also supplies anterior-thigh sensation through anterior cutaneous branches and medial leg sensation via the saphenous nerve.
The lateral femoral cutaneous nerve (L2–L3) passes close to the ASIS beneath or through the inguinal ligament. Entrapment causes purely sensory meralgia paraesthetica, without weakness or reflex loss.
Differentiate femoral neuropathy from L3/L4 radiculopathy by distribution and associated signs.
Cover the entire myopectineal orifice including direct, indirect and femoral spaces.

3. Complications and repair

Femoral hernias have a relatively high risk of strangulation.

4. Abdominal wall anatomy

The spermatic cord acquires the internal spermatic fascia from transversalis fascia as it passes through the deep inguinal ring. The external spermatic fascia derives from external oblique aponeurosis, while the cremasteric muscle and fascia arise mainly from internal oblique.

Superficial ring is an opening in external oblique aponeurosis.

Applied anatomy and pathology

The ilioinguinal nerve travels in the canal but does not enter via the deep ring.
Beware an aberrant obturator artery near the lacunar ligament (corona mortis).
Lateral femoral cutaneous nerve is purely sensory and usually L2–L3.

Clinical recognition and differential diagnosis

Remove compression, modify clothing, optimise weight and use neuropathic pain treatment if necessary.
Quadriceps weakness and reduced patellar reflex suggest femoral neuropathy.
Compression is associated with obesity, pregnancy and tight garments.

Investigations and diagnostic interpretation

Day-case suitability requires broader assessment than a single reflex test.
Assess postural blood pressure and symptoms of orthostatic hypotension.
Warm substantial IV fluid volumes and blood products appropriately.
Core biopsy may be used when excision is impractical or unsafe.

Management and operative principles

Protect the exposed placode and seek urgent specialist neonatal/neurosurgical management.
Avoid bag-mask ventilation where possible; secure the airway and decompress the stomach.
Avoid dangerous fixation in the triangles of pain and doom.

Measurements, staging and thresholds

NICE CG65 defines inadvertent perioperative hypothermia as core temperature below 36°C and advises active warming before induction for elective surgery until the patient reaches at least 36°C. Clinical urgency, such as major haemorrhage, is an exception.
At least every 30 minutes under NICE CG65.

Common examiner traps

A dermatome is not the same as the vertebral level of a cord lesion; formal neurological examination is required.
Do not confuse TEP with TAPP; both place mesh preperitoneally but only TAPP enters the peritoneal cavity.
Do not mistake it for L2–L3 radiculopathy, which may produce back pain or motor/reflex abnormalities.
Do not infer that reduced variability alone mandates inpatient surgery; assess overall risk.
Do not divide the lacunar ligament blindly because of possible aberrant obturator vessels.

Rapid-recall exam pearls

Anterolateral thigh sensory loss with intact power and reflexes suggests meralgia paraesthetica.
Elective surgery: core temperature must be ≥36°C before induction under NICE CG65.
Neonate + bowel in left chest = Bochdalek from pleuroperitoneal canal nonclosure.
Knee extension weakness after a groin block points to femoral nerve involvement.
Loss of knee extension after groin surgery localises to the femoral nerve.

Acute abdomen and peritonitis

Overview. Abdominal rigidity, shock and systemic deterioration signal a potentially time-critical intra-abdominal process; resuscitation and source control are essential.

Topic map — key distinctions

Subtopic	Defining feature / key principle
Peritonitis	Warm peritoneal lavage transfers heat directly to the body core and is an active internal rewarming technique.
Investigations and imaging	Warm peritoneal lavage transfers heat directly to the body core and is an active internal rewarming technique.

1. Peritonitis

Warm peritoneal lavage transfers heat directly to the body core and is an active internal rewarming technique. In severe hypothermia, especially with instability or arrest, extracorporeal life support (VA-ECMO/CPB) is preferred where available; the question compares only the listed measures.

Localised peritonism or guarding, especially with systemic deterioration.
Peritoneal lavage is active internal warming; VA-ECMO is the preferred advanced option for unstable severe hypothermia.

2. Investigations and imaging

Use warmed oxygen and IV fluids as supportive active measures.
Serial examinations help detect evolution of focal signs.
Adults with suspected adrenal crisis: hydrocortisone 100 mg IV/IM immediately.
Peritoneal lavage is active internal warming; VA-ECMO is the preferred advanced option for unstable severe hypothermia.
Suspected adrenal crisis is treated first, confirmed later.

Clinical recognition and differential diagnosis

Safety-net for worsening pain, persistent vomiting, fever, reduced urine output or lethargy.
Appendicitis can begin with poorly localised abdominal pain.

Investigations and diagnostic interpretation

Prolonged supraphysiological glucocorticoids can suppress the HPA axis. Acute illness may precipitate adrenal crisis, which requires immediate parenteral hydrocortisone and IV isotonic fluids without waiting for diagnostic confirmation. Assess glucose, potassium and alternative causes of shock simultaneously.
Use ultrasound when imaging for appendicitis is clinically indicated in children.

Measurements, staging and thresholds

Continue hydrocortisone 200 mg over 24 hours or 50 mg every six hours until stabilised.
Severe hypothermia is commonly defined as core temperature below 28°C.

Common examiner traps

Do not assume warmed fluids or blankets alone are adequate for a profoundly unstable hypothermic patient.
Secondary adrenal insufficiency usually preserves aldosterone; hyperkalaemia is not obligatory.

Rapid-recall exam pearls

Peritoneal lavage is active internal warming; VA-ECMO is the preferred advanced option for unstable severe hypothermia.
A stable child with an undifferentiated acute abdomen often needs reassessment, not a guessed diagnosis.
Suspected adrenal crisis is treated first, confirmed later.

Colorectal, intestinal and abdominal wall

Overview. Abdominal symptoms must be linked to segmental anatomy, inflammatory bowel disease and mechanical obstruction before management.

Topic map — key distinctions

Subtopic	Defining feature / key principle
Appendix and colon	Most appendiceal NETs are found incidentally after appendicectomy.
Small intestine and obstruction	Peyer patches are aggregated lymphoid follicles in the distal small bowel.
Hernia and wall	A tender irreducible inguinal swelling with obstructive vomiting and abdominal distension in an infant strongly suggests an incarcerated hernia, with strangulation possible when there is systemic illness or skin…
Colorectal red flags	A cirrhotic patient with massive haematemesis may have variceal bleeding, but other sources remain possible.

1. Appendix and colon

Most appendiceal NETs are found incidentally after appendicectomy.
Carcinoid syndrome is uncommon in localised appendiceal NET.
Appendiceal NET size greater than 2 cm is an established high-risk feature for regional nodal spread. Contemporary ENETS guidance supports completion right hemicolectomy for tumours over 2 cm after appropriate staging and multidisciplinary consideration.
Grade, mesoappendiceal invasion, lymphovascular invasion and margin status.
Appendiceal NET >2 cm: consider completion right hemicolectomy after staging and MDT.

2. Small intestine and obstruction

Peyer patches are aggregated lymphoid follicles in the distal small bowel.

3. Hernia and wall

A tender irreducible inguinal swelling with obstructive vomiting and abdominal distension in an infant strongly suggests an incarcerated hernia, with strangulation possible when there is systemic illness or skin change. This is an emergency requiring resuscitation and immediate paediatric surgical evaluation; attempted reduction is inappropriate when strangulation is suspected.

Indirect inguinal hernia in children arises from a patent processus vaginalis.
Complicated hernias need prompt surgical assessment.
Most uncomplicated paediatric umbilical hernias close spontaneously during early childhood. In an asymptomatic infant, observation is appropriate; elective repair is commonly considered if persistent around age 4–5 years or if complications arise.
Infant + irreducible groin swelling + bilious vomiting = obstructed inguinal hernia.
Observe an uncomplicated infant umbilical hernia; most close spontaneously.

4. Colorectal red flags

A cirrhotic patient with massive haematemesis may have variceal bleeding, but other sources remain possible.

Start antibiotics and vasoactive therapy early when variceal bleeding is suspected.
Prolonged PT in the source did not prove coagulopathy was the bleeding source.

Applied anatomy and pathology

Invasive carcinoma requires assessment of invasion beyond the muscularis mucosae into the submucosa.
Secretory IgA, transported across epithelium by the polymeric immunoglobulin receptor.
Inferior rectal branches of the pudendal nerve.

Clinical recognition and differential diagnosis

Classical FAP is an autosomal dominant syndrome caused by a pathogenic germline variant in the APC tumour-suppressor gene on chromosome 5q. Loss of APC dysregulates beta-catenin/Wnt signalling and drives colorectal adenoma formation.
Microscopy alone may not distinguish E. histolytica from E. dispar; antigen/PCR improves specificity.
Airway intervention is indicated when protection is inadequate, not automatically for every GI bleed.

Investigations and diagnostic interpretation

CT abdomen and pelvis provides cross-sectional localisation of the obstruction, identifies a possible tumour and assesses perforation, ischaemia or metastatic disease. Intravenous contrast is preferred when clinically appropriate, but should not delay urgent assessment when contraindicated.
Gastrointestinal potassium loss can cause hypokalaemia, promoting atrial and ventricular arrhythmias through altered membrane repolarisation. Check potassium, magnesium, renal function and ECG; replace deficits and address the diarrhoeal cause.
Entamoeba histolytica invades the colonic mucosa and can cause dysentery with blood and mucus. Species-specific stool antigen or PCR helps distinguish pathogenic E. histolytica from morphologically similar nonpathogenic amoebae.
The lymphatics of the anal margin and lower anal canal below the dentate line preferentially drain to superficial inguinal nodes. This anatomical distinction guides examination and radiotherapy fields.

Management and operative principles

Initial management includes resuscitation, electrolyte correction and surgical assessment.
Defect size influences closure probability but does not alone mandate infant surgery.
Upper anal canal drainage includes internal iliac and mesorectal pathways.
Arrange urgent endoscopy after appropriate initial resuscitation.

Measurements, staging and thresholds

Cross-sectional CT of chest, abdomen and pelvis provides standard anatomic staging for colorectal cancer and characterises suspected lung and liver metastases. Resectability, treatment sequence and need for additional targeted imaging can then be discussed by the MDT.
Size, villous architecture and high-grade dysplasia increase advanced-neoplasia risk.
Tumours 1–2 cm require individualised evaluation of grade, margins and invasion.
Test sensitivity and specificity depend on the threshold and population.

Common examiner traps

Atrial fibrillation has many causes; electrolyte depletion is a precipitant, not a pathognomonic diagnosis.
Never claim FIT is simply “sensitive” or “specific” without stating the threshold and target condition.
An arrhythmia with diarrhoea should not be attributed to potassium alone if magnesium is also depleted.
Do not replace folate alone before excluding B12 deficiency when neurological symptoms are present.
Do not treat invasive amoebiasis with metronidazole alone without subsequent luminal eradication.

Rapid-recall exam pearls

Haematemesis with shock and inability to protect airway: resuscitation and airway take priority over diagnosis alone.
FIT = antibody-based detection of human haemoglobin, not the guaiac peroxidase reaction.
Appendiceal NET >2 cm: consider completion right hemicolectomy after staging and MDT.
Infant + irreducible groin swelling + bilious vomiting = obstructed inguinal hernia.
CT abdomen/pelvis is the key diagnostic test for suspected large-bowel obstruction.

Colorectal, rectal and anal disease

Overview. Separate colonic, rectal and anal disorders by their characteristic pain, bleeding pattern, bowel habit and relevant imaging or endoscopy.

Topic map — key distinctions

Subtopic	Defining feature / key principle
Colorectal cancer and screening	Dukes C colorectal cancer has regional lymph-node involvement regardless of the depth of primary wall invasion.
Diverticular disease	Diverticulosis is common and can coexist with colorectal cancer, but uncomplicated diverticular disease is not regarded as a premalignant condition.
Inflammatory bowel disease	Airway disease, including bronchiectasis, can occur as an extraintestinal manifestation of both ulcerative colitis and Crohn disease.
Anal fissure	Primary fissures are overwhelmingly posterior midline.
Haemorrhoids	Evaluate red flags and do not attribute all rectal bleeding to haemorrhoids without appropriate assessment.
Perianal fistula	Pelvic MRI maps complex perianal fistula tracts; abscess requires drainage.

1. Colorectal cancer and screening

Dukes C colorectal cancer has regional lymph-node involvement regardless of the depth of primary wall invasion. Modern practice uses the more granular TNM system to guide prognostication and adjuvant treatment decisions.

A small polyp burden does not exclude hereditary colorectal cancer.
Diverticulosis is common and can coexist with colorectal cancer, but uncomplicated diverticular disease is not regarded as a premalignant condition. Alarm symptoms still require appropriate cancer evaluation.
Diverticulitis may temporarily mimic colorectal cancer clinically or radiologically.
Colorectal cancer surveillance depends on disease extent and duration.
CEA is not a standalone screening test for colorectal cancer.
FAP carries a high colorectal cancer risk if untreated.

2. Diverticular disease

Diverticulosis is common and can coexist with colorectal cancer, but uncomplicated diverticular disease is not regarded as a premalignant condition. Alarm symptoms still require appropriate cancer evaluation.

A colovesical fistula creates an abnormal connection between colon and bladder; diverticular disease is a common benign cause. Pneumaturia and recurrent polymicrobial urinary infections are typical, and CT may show intravesical air or adherence of sigmoid colon to bladder.
Inflammation of sigmoid diverticula produces left-sided abdominal pain, fever and focal tenderness. CT evidence of peridiverticular fat stranding with wall thickening supports the diagnosis and helps exclude complications such as abscess or free perforation.
Technetium-99m pertechnetate is taken up by ectopic gastric mucosa within a Meckel diverticulum; sensitivity is lower when that mucosa is absent.
Diverticular disease and IBD are differentials; the original recall diagnosis remains unverified.
Meckel diverticulum is a true diverticulum arising from the antimesenteric ileal border.
Diverticulitis may temporarily mimic colorectal cancer clinically or radiologically.

3. Inflammatory bowel disease

Airway disease, including bronchiectasis, can occur as an extraintestinal manifestation of both ulcerative colitis and Crohn disease. It is less common than musculoskeletal, skin, eye or hepatobiliary manifestations. Alternative causes of bronchiectasis must still be investigated; coexistence does not prove causation.

Ulcerative colitis is associated with peripheral arthritis, uveitis/iritis, primary sclerosing cholangitis and severe colitis complications such as toxic megacolon. Polyarteritis nodosa is a systemic medium-vessel necrotising vasculitis and is not a typical IBD-associated manifestation.
Crohn disease is a transmural inflammatory bowel disorder that can cause perianal abscesses and fistulas as well as diarrhoea, abdominal pain and weight loss. Persistent or recurrent fistula with systemic gastrointestinal symptoms should prompt IBD evaluation.
Crohn disease may involve any gastrointestinal segment, commonly the terminal ileum, and causes discontinuous transmural inflammation. Non-caseating granulomas support Crohn disease when infection and other granulomatous causes are excluded, though granulomas are not present in every biopsy.
Pelvic MRI delineates fistula anatomy, secondary tracts, sphincter involvement and occult collections in perianal Crohn disease. Examination under anaesthesia complements imaging and allows drainage or seton placement where required. Sepsis or an abscess requires prompt drainage rather than delay for elective mapping.
Crohn disease is a segmental, transmural inflammatory bowel disease that can penetrate through the bowel wall, creating enteroenteric or enterocolic fistulae. Terminal ileal involvement, weight loss and chronic diarrhoea strengthen the diagnosis.
Complex Crohn fistulae crossing substantial sphincter muscle require control of sepsis while preserving continence. Loose setons permit ongoing drainage and are often combined with medical therapy, including biologics, after sepsis is controlled.

4. Anal fissure

Primary fissures are overwhelmingly posterior midline. A lateral, multiple, broad or atypical fissure raises concern for secondary disease, including Crohn disease, infection and malignancy. Chronic diarrhoea and weight loss reinforce the need for inflammatory bowel disease assessment.

A primary anal fissure is a linear tear in the anoderm, usually posterior in the midline, where local perfusion is relatively reduced and sphincter spasm may perpetuate pain and non-healing.
Atypical lateral fissures require consideration of Crohn disease, STI, tuberculosis and malignancy.
Atypical lateral fissures raise concern for Crohn disease, infection or malignancy.
Persistent atypical or lateral fissures require assessment for underlying disease.
Assess for seepage, hygiene products, dermatitis, fissure and haemorrhoids.
Posterior midline is the commonest site for primary fissures.

5. Haemorrhoids

Evaluate red flags and do not attribute all rectal bleeding to haemorrhoids without appropriate assessment.

In adults, haemorrhoids should not automatically be assumed to be the sole source of iron loss.
Radial folds or separate columns favour prolapsing haemorrhoids or mucosal prolapse.
Assess for seepage, hygiene products, dermatitis, fissure and haemorrhoids.
Large irreducible grade IV haemorrhoids or substantial symptomatic combined internal–external disease are generally treated with excisional haemorrhoidectomy after shared decision-making. Conservative measures remain useful but are not definitive for severe irreducible prolapse.
Concentric folds = full-thickness rectal prolapse; radial folds = haemorrhoidal/mucosal prolapse.
Irreducible grade IV haemorrhoids generally favour excisional haemorrhoidectomy.

6. Perianal fistula

Pelvic MRI maps complex perianal fistula tracts; abscess requires drainage.
Look for perianal fistulae, abscesses and other Crohn features.
Perianal fistulas can precede luminal Crohn diagnosis.
A nonhealing perianal fistula plus diarrhoea and weight loss suggests Crohn disease.
MRI pelvis is the investigation of choice for a complex perianal fistula.
Transmural Crohn inflammation can cause perianal fistulas.

7. Anorectal anatomy and pelvic floor

Infection of anal glands at the dentate line.

8. Acute appendicitis and obstruction

Appendiceal luminal obstruction, due to lymphoid hyperplasia, an appendicolith or less commonly a tumour, promotes secretion retention, increased intraluminal pressure, venous outflow impairment, bacterial proliferation and eventual ischaemic injury. Not every case has a demonstrable obstruction.

Appendicolith is a common obstructive factor and may affect treatment selection.
Luminal obstruction is one mechanism of appendiceal inflammation.
Appendicitis commonly begins with luminal obstruction and rising intraluminal pressure.
Laparoscopy directly inspects the appendix and pelvic organs, allowing diagnosis of appendicitis or an alternative pelvic cause and treatment during the same anaesthetic. The decision to operate versus obtain further imaging depends on local pathways, clinical stability and diagnostic certainty.
Rovsing sign refers to pain elicited in the right lower abdomen by palpation of the left lower abdomen in suspected appendicitis. It is a supportive peritoneal irritation sign rather than a standalone diagnostic test.
Persistent focal peritonism requires reassessment for appendicitis or another surgical cause.

Applied anatomy and pathology

For most nonmetastatic anal-canal squamous carcinomas, definitive concurrent radiotherapy with mitomycin plus fluoropyrimidine (5-FU or capecitabine) offers organ and sphincter preservation. Abdominoperineal excision is generally reserved for persistent or recurrent local disease.
Mupirocin applied to the anterior nares is commonly used to reduce MRSA nasal carriage, usually alongside an antiseptic skin-washing regimen according to local infection-control policy. Colonisation is not itself an indication for systemic vancomycin treatment.
The external oblique aponeurosis forms the anterior wall of the inguinal canal and is split in the direction of its fibres to open the canal and expose the spermatic cord. The ilioinguinal nerve should be identified and protected where possible.

Clinical recognition and differential diagnosis

Large-volume intestinal fluid loss carries potassium and bicarbonate, causing total-body potassium depletion and frequently a normal-anion-gap metabolic acidosis. The observed plasma potassium can also reflect renal function and severity of dehydration.
Ulcerative colitis produces continuous colonic mucosal inflammation extending proximally from the rectum, with bloody diarrhoea and urgency. Extraintestinal manifestations may include peripheral arthritis, episcleritis/uveitis and primary sclerosing cholangitis.
Large distal colorectal villous adenomas can secrete electrolyte-rich mucus and water, causing the McKittrick–Wheelock syndrome of secretory diarrhoea, hypokalaemia, hyponatraemia, dehydration and prerenal renal impairment. Potassium depletion is the classic exam finding.

Investigations and diagnostic interpretation

The Mann–Whitney U test is a non-parametric rank-based test for two independent groups when normality assumptions for an unpaired t test are unsuitable. It compares distributions or stochastic ordering; interpreting it specifically as a median comparison requires assumptions about similar distribution shapes.
With adequate lead time, stable iron-deficiency anaemia is commonly treated with oral iron, alongside investigation of blood loss and optimisation before elective surgery. IV iron is considered when oral therapy is ineffective, not tolerated or time is too short.
Ileocolonoscopy with terminal ileal intubation and systematic biopsies is a cornerstone of initial evaluation for suspected inflammatory bowel disease. It demonstrates mucosal inflammation, distribution and histological features; cross-sectional small-bowel imaging complements endoscopy for extent and complications.
A parastomal hernia is an incisional hernia at the abdominal-wall aperture around a stoma. Entrapped bowel can obstruct or strangulate. Urgent examination, resuscitation and CT/surgical assessment are required when obstruction is suspected.

Management and operative principles

Fournier gangrene is a rapidly progressive necrotising infection of perineal and genital fascial planes. Disproportionate pain, systemic sepsis, crepitus and skin necrosis require immediate broad-spectrum antimicrobials, resuscitation and urgent surgical debridement.
Recent antibiotic exposure and hospitalisation followed by watery diarrhoea are typical of Clostridioides difficile infection. Toxin-mediated colonic inflammation can cause pseudomembranous colitis, and the diagnosis requires appropriate stool testing in a symptomatic patient.
ERAS combines preoperative education, multimodal analgesia, judicious fluids, early oral intake and mobilisation to reduce surgical stress and accelerate recovery. Shorter length of stay is a well-established programme-level outcome.
The ilioinguinal nerve (primarily L1) traverses part of the inguinal canal and exits via the superficial ring, supplying skin near the groin and genital region. It is vulnerable to traction, division and entrapment in mesh repair.

Measurements, staging and thresholds

Low bicarbonate identifies metabolic acidosis, likely from lactate generation during hypoperfusion. The simultaneously raised PaCO₂ indicates alveolar hypoventilation and a second primary respiratory acidosis. Winter’s formula predicts a compensatory PaCO₂ around 33.5 ± 2 mmHg, far below the measured ~54 mmHg.
T1 colorectal carcinoma invades submucosa but not muscularis propria. Metastasis in two or three regional lymph nodes is N1b. With no distant metastasis, the stage components are pT1 pN1b M0. Nodal involvement makes this stage III despite the shallow primary invasion.
Grade I bleeds without prolapse; II reduces spontaneously; III requires manual reduction; IV is irreducible.
Colon continuity can improve fluid and energy salvage but does not compensate for only 5 cm of jejunum.

Common examiner traps

Do not prescribe lifelong parenteral nutrition based on length alone if absorption is adequate; assess actual nutritional and fluid balance.
An epidural is not mandatory for every cholecystectomy and is not appropriate with unsafe coagulation or certain haemodynamic states.
Do not treat every post-colonoscopy pneumoperitoneum with immediate colectomy; equally, never ignore clinical deterioration.
A positive molecular test alone may indicate colonisation; correlate with diarrhoeal illness and toxin-testing algorithms.
Hartmann is not mandatory for every diverticular perforation: stable selected patients may undergo primary anastomosis.

Rapid-recall exam pearls

Bleeding Meckel in a child: consider a pertechnetate scan; inflamed Meckel in a stable adult: CT is often most useful.
Small contained perforation plus stability and no peritonitis may be managed non-operatively under close observation.
Organ-space abscess after perforated appendicitis = mixed colonic aerobes and anaerobes, not automatically S. aureus.
Short interval to surgery + proven iron deficiency + stable patient: consider IV iron, not automatic transfusion.
Pruritus ani management begins with identifying and removing irritants and controlling moisture or seepage.

Hepatobiliary and pancreatic

Overview. Right-upper-quadrant pain, jaundice and upper abdominal sepsis require discrimination among gallbladder, bile duct, liver and pancreatic pathology.

Topic map — key distinctions

Subtopic	Defining feature / key principle
Gallstone disease and cholecystitis	Chronic extravascular haemolysis increases bilirubin turnover, favouring black pigment gallstone formation.
Cholangitis and obstruction	Fever, right upper-quadrant pain and jaundice constitute Charcot triad of acute cholangitis.
Pancreatitis and complications	Preserved pancreatic enhancement with inflammatory oedema and fat stranding supports interstitial oedematous pancreatitis rather than pancreatic parenchymal necrosis.
Pancreatic neoplasia	Biopsy-confirmed liver metastasis makes the pancreatic cancer unresectable in this scenario.
Liver disease and portal hypertension	Chronic haemolysis increases bilirubin production, creating conditions for precipitation of unconjugated bilirubin as calcium bilirubinate in the gallbladder.

1. Gallstone disease and cholecystitis

Chronic extravascular haemolysis increases bilirubin turnover, favouring black pigment gallstone formation. Intermittent transient cystic duct obstruction produces episodic biliary colic without sustained fever or inflammatory findings.

Haemolysis + episodic postprandial RUQ pain = pigment gallstone biliary colic.
Gallstones do not automatically mean cholecystitis; look for persistent pain and inflammation.
Recurrent symptomatic gallstones warrant surgical assessment in the context of haemolytic disease.
Asymptomatic gallstones generally do not need prophylactic cholecystectomy.
Ileal disease or resection increases gallstone risk.
Ultrasound is first-line for suspected gallstones.

2. Cholangitis and obstruction

Fever, right upper-quadrant pain and jaundice constitute Charcot triad of acute cholangitis. A biliary stent can obstruct or become infected, leading to infected, pressurised bile. Obtain cultures, begin resuscitation and appropriate antibiotics, and arrange urgent assessment for biliary decompression, often ERCP with stent exchange or clearance, particularly if severe.

Severe acute cholangitis with shock requires resuscitation, IV antibiotics and urgent relief of infected biliary obstruction. ERCP is generally the preferred drainage route where feasible; endoscopic stenting or nasobiliary drainage can achieve decompression, with definitive stone clearance when safe. Percutaneous drainage is an alternative if ERCP cannot be achieved.
A retained CBD stone may present after cholecystectomy with biliary colic, cholestatic liver enzymes or jaundice. Ultrasound and MRCP help define obstruction, while ERCP enables sphincterotomy and stone extraction when appropriate.
A common bile duct stone can obstruct biliary drainage, producing biliary pain, jaundice, conjugated hyperbilirubinaemia and a cholestatic enzyme pattern. Ultrasound may demonstrate ductal dilatation even when the stone is not visualised. MRCP or EUS can clarify uncertain cases; ERCP is used therapeutically for duct clearance when indicated.
CBD stones may cause obstructive jaundice, pancreatitis or ascending cholangitis.
Pain with fever and jaundice raises concern for ascending cholangitis.
Severe cholangitis + organ dysfunction = antibiotics/resuscitation AND urgent duct drainage, usually ERCP.

3. Pancreatitis and complications

Preserved pancreatic enhancement with inflammatory oedema and fat stranding supports interstitial oedematous pancreatitis rather than pancreatic parenchymal necrosis. Necrosis is suggested by non-enhancing pancreatic tissue or necrotic peripancreatic collections. Pseudocyst and walled-off necrosis generally require time to mature, usually about four weeks.

Tetany, perioral paraesthesia and carpopedal spasm are characteristic of reduced ionised calcium. Severe pancreatitis can cause hypocalcaemia through calcium sequestration in fat necrosis (saponification), systemic inflammation and other factors. Ionised calcium is particularly informative in critically ill patients because total calcium is influenced by albumin.
Enhancing pancreas with oedema = interstitial oedematous pancreatitis, unless necrosis elsewhere is demonstrated.
Pancreatitis + chalky fat deposits = enzymatic fat necrosis with saponification.
Severe systemic inflammation in acute pancreatitis can produce diffuse alveolar-capillary injury, noncardiogenic pulmonary oedema and acute respiratory distress syndrome (ARDS), causing hypoxaemia and bilateral opacities.
Necrotising pancreatitis is identified on contrast-enhanced imaging by non-enhancing pancreatic tissue when imaging is appropriately timed.
Severe pancreatitis may be associated with low serum calcium, though mechanisms are multifactorial.

4. Pancreatic neoplasia

Biopsy-confirmed liver metastasis makes the pancreatic cancer unresectable in this scenario. For symptomatic malignant biliary obstruction, endoscopic placement of a self-expanding metal stent is preferred to surgical bypass when feasible, alongside oncology and supportive care.

Distant liver metastasis indicates stage IV pancreatic cancer.

5. Liver disease and portal hypertension

Chronic haemolysis increases bilirubin production, creating conditions for precipitation of unconjugated bilirubin as calcium bilirubinate in the gallbladder. These hard black pigment stones are associated with haemolytic diseases and cirrhosis.

Chronic hepatitis B is a major risk factor for hepatocellular carcinoma, which can occur even without established cirrhosis. In an at-risk patient, characteristic multiphasic contrast imaging showing arterial phase hyperenhancement and washout strongly supports HCC.
HBV-associated HCC may occur without cirrhosis.
Baveno VII recommends starting vasoactive treatment as soon as acute variceal bleeding is suspected and giving antibiotic prophylaxis to patients with cirrhosis and upper GI bleeding. These are adjuncts to resuscitation, restrictive transfusion when appropriate and early endoscopic haemostasis.

Applied anatomy and pathology

Thyroid hormones support LDL-receptor expression and lipid turnover. Overt hypothyroidism decreases hepatic LDL clearance, frequently increasing total and LDL cholesterol. Treating thyroid deficiency may improve the lipid profile and should be considered when evaluating secondary dyslipidaemia.
A symptomatic post-cholecystectomy collection should be drained to obtain source control and determine its nature. A biloma may arise from a cystic-duct stump or accessory duct leak. ERCP with sphincterotomy/stenting is often required if a leak persists; major duct injuries need HPB specialist assessment.
Pancreatic lipase hydrolyses triglycerides in adjacent fat, releasing free fatty acids. These combine with calcium to form chalky deposits (saponification), producing enzymatic fat necrosis.

Clinical recognition and differential diagnosis

Heterozygous familial hypercholesterolaemia commonly results from pathogenic LDLR variants causing reduced hepatic clearance of LDL particles. Other recognised causes include APOB variants and PCSK9 gain-of-function. Very high LDL-C, tendon xanthomas and premature coronary disease in relatives are characteristic.
The gallbladder fundus lies near the tip of the right ninth costal cartilage, where the right costal margin meets the lateral edge of rectus abdominis (linea semilunaris). Murphy sign is inspiratory arrest during palpation at this region.
Primary sclerosing cholangitis is strongly associated with inflammatory bowel disease, especially ulcerative colitis. The combination of cholestatic biliary strictures and continuous colitis is highly characteristic.

Investigations and diagnostic interpretation

Lack of enhancement of pancreatic parenchyma on appropriately timed contrast CT is characteristic of pancreatic necrosis. The revised Atlanta classification distinguishes early acute necrotic collections from walled-off necrosis developing after approximately four weeks.
Clip-related obstruction or transection of the common hepatic/common bile duct may cause early postoperative obstructive jaundice and requires prompt hepatobiliary specialist assessment. Imaging maps anatomy and associated collections; definitive management depends on injury pattern and stability.
Impaired bile flow leads to retention of bile-related substances. Bile acids are a classic examination association, although contemporary evidence also implicates lysophosphatidic acid and other mediators; itch severity does not reliably track bile-acid concentration.
Activated pancreatic elastase degrades elastin in blood-vessel walls and can contribute to vascular damage, haemorrhage and pancreatic necrosis. Trypsin is an important upstream activator of other pancreatic proenzymes, but the question specifically asks which enzyme attacks vascular elastic tissue.

Management and operative principles

The upper rectum drains via the superior rectal vein into the inferior mesenteric and portal venous systems, so the liver is a common first site of haematogenous colorectal metastasis. Distal rectal drainage may also enter systemic veins, allowing lung metastases.
Refractory hypotension, weakness, vomiting, hypoglycaemia or hyponatraemia; treat immediately with parenteral hydrocortisone and fluid resuscitation.
When unresectability is discovered during laparotomy or endoscopic drainage fails and operative palliation is appropriate.
NICE recommends endoscopically placed self-expanding metal stents over surgical biliary bypass in unresectable disease.

Measurements, staging and thresholds

Severe acute pancreatitis may cause low serum calcium through fat saponification and systemic inflammation. Hypocalcaemia lengthens the ventricular action potential and can prolong the corrected QT interval.
Prednisolone doses above approximately 4–6 mg/day for at least 3–4 weeks can place patients at risk of HPA-axis suppression.
Dutch Lipid Clinic Network criteria; NICE also supports DNA testing and cascade screening where indicated.
Tumour burden, liver reserve and performance status (for example BCLC staging).

Common examiner traps

A diagnosis of Down syndrome alone does not establish inability to use PCA. The reconstruction explicitly documents failed functional understanding and severe pain.
Do not confuse first-line diagnostic ultrasound with therapeutic ERCP; the original recall omitted severity and asked an ambiguous “test of choice.”.
Without imaging, retained CBD stone and duct injury may both be plausible; the reconstructed MRCP finding makes the SBA answer unambiguous.
Distal rectal cancer can reach lungs through systemic venous pathways; not every rectal tumour drains exclusively to portal blood.
CVP alone cannot reliably separate cardiogenic from non-cardiogenic pulmonary oedema; the original recall used CVP misleadingly.

Rapid-recall exam pearls

Caecal volvulus generally needs surgery; sigmoid volvulus may first undergo endoscopic decompression when uncomplicated.
A resectable hepatic-flexure carcinoma generally requires an oncological right-sided colectomy, not local excision.
PCA is patient-controlled, never family-controlled; use monitored titrated rescue analgesia if PCA cannot be used.
Enhancing pancreas with oedema = interstitial oedematous pancreatitis, unless necrosis elsewhere is demonstrated.
Chronic steroid user + general anaesthesia + vomiting = parenteral stress coverage, not omission of steroids.

Hepatobiliary, pancreatic and splenic

Overview. Liver, pancreatic and splenic lesions are interpreted by vascular and ductal anatomy and by the clinical presentation of trauma, sepsis or malignancy.

Topic map — key distinctions

Subtopic	Defining feature / key principle
Splenic anatomy and trauma	Do not call the spleen a primary lymphoid organ.

1. Splenic anatomy and trauma

Do not call the spleen a primary lymphoid organ.
Red pulp macrophages remove aged, rigid or opsonised erythrocytes and participate in clearance of blood-borne organisms. The spleen is a secondary lymphoid organ with red and white pulp.

Clinical recognition and differential diagnosis

Brown pigment stones are more associated with infected or stagnant bile ducts.
Daughter cysts and detached membranes are characteristic sonographic findings.
Class I clean, provided no tract is entered or infection present.

Investigations and diagnostic interpretation

White pulp supports immune responses to blood-borne antigens.

Management and operative principles

Controlled entry into the biliary tract without unusual contamination is class II (clean-contaminated). The recovered recall labels this operation clean; that source annotation conflicts with standard surgical wound classification and has been corrected in the reconstruction.

Measurements, staging and thresholds

Cystic echinococcosis caused by Echinococcus granulosus produces hepatic hydatid cysts; daughter cysts, floating membranes and calcification are characteristic imaging clues. Treatment depends on cyst stage, size, complications and local expertise.

Common examiner traps

An answer printed in an unverified recall can be wrong; absence of bile spillage does not make biliary entry class I.
Do not confuse black pigment stones with brown pigment stones from biliary infection.
Do not confuse hepatocyte hyperplasia with stellate-cell scar formation.
Do not aspirate a suspected hydatid cyst as if it were a simple abscess.
Do not call the spleen a primary lymphoid organ.

Rapid-recall exam pearls

Red pulp = macrophage-rich erythrocyte filtration; white pulp = lymphoid immunity.
Hepatic cyst with daughter cysts in a shepherd suggests hydatid disease.
After hepatectomy, regeneration mainly comes from existing hepatocytes.
Elective uncomplicated cholecystectomy = class II clean-contaminated.
Chronic haemolysis produces black pigment gallstones.

Oesophageal and upper GI

Overview. Dysphagia, reflux and upper gastrointestinal bleeding require characterisation of symptom progression, red flags and likely site of disease.

Topic map — key distinctions

Subtopic	Defining feature / key principle
Oesophageal motility and malignancy	Malignancy at the gastro-oesophageal junction may mimic achalasia; rapid symptom onset, older age and marked weight loss are concerning.
GORD and Barrett disease	Distal oesophageal adenocarcinoma is linked to chronic reflux, obesity and Barrett oesophagus.
Peptic ulcer and upper GI bleed	Meckel diverticulum can contain ectopic gastric mucosa that secretes acid and ulcerates adjacent ileal mucosa, producing painless, sometimes substantial lower gastrointestinal bleeding in a young child.
Gastric and oesophageal cancer	Meckel diverticulum can contain ectopic gastric mucosa that secretes acid and ulcerates adjacent ileal mucosa, producing painless, sometimes substantial lower gastrointestinal bleeding in a young child.
Varices and portal hypertension	Beta-blockers reduce portal inflow and portal pressure; EVL eradicates endoscopically accessible varices.

1. Oesophageal motility and malignancy

Malignancy at the gastro-oesophageal junction may mimic achalasia; rapid symptom onset, older age and marked weight loss are concerning.

Longstanding achalasia is associated with increased risk of oesophageal squamous-cell carcinoma, probably through chronic stasis, mucosal irritation and inflammation. New or worsening dysphagia and weight loss warrant urgent endoscopic evaluation and biopsy rather than attribution to established achalasia.
Metastatic obstructing oesophageal cancer with urgent dysphagia relief needed: consider self-expanding stent.
Raynaud with dysphagia is not synonymous with achalasia; the LES pressure/relaxation pattern distinguishes them.
Do not assume all new dysphagia in known achalasia is benign disease progression.
Achalasia involves impaired lower oesophageal sphincter relaxation and absent normal peristalsis.
Achalasia: impaired LES relaxation with absent normal peristalsis.

2. GORD and Barrett disease

Distal oesophageal adenocarcinoma is linked to chronic reflux, obesity and Barrett oesophagus.

Barrett oesophagus is associated with chronic gastro-oesophageal reflux.
Self-expanding stents can provide rapid relief but may migrate or cause reflux, pain and perforation.
Systemic sclerosis oesophageal disease often causes reflux, regurgitation and dysphagia.
Migration, reflux, chest pain, bleeding, perforation and recurrent obstruction.
Tube feeding does not prevent aspiration of saliva or refluxed contents.
Controlled dilatation, alongside adequate reflux suppression.

3. Peptic ulcer and upper GI bleed

Meckel diverticulum can contain ectopic gastric mucosa that secretes acid and ulcerates adjacent ileal mucosa, producing painless, sometimes substantial lower gastrointestinal bleeding in a young child. The absence of colicky pain or a palpable mass makes intussusception less likely. Resuscitation and assessment of haemodynamic stability precede diagnostic tests.

Peptic ulcers can bleed, perforate, penetrate and produce scarring/obstruction. Splenic vein thrombosis is classically associated with pancreatitis, pancreatic neoplasms and local inflammatory or compressive conditions, not routine peptic ulcer disease.
Gastrinoma causes inappropriate gastrin secretion, marked gastric acid hypersecretion, recurrent ulcers and sometimes diarrhoea. Confirmation requires interpreting fasting gastrin with gastric pH and selected provocative tests while considering PPI effects.
Ectopic gastric mucosa is responsible for acid-related ulceration and bleeding.
Ectopic gastric mucosa can ulcerate adjacent ileal mucosa and cause bleeding.
A gastrinoma secretes gastrin, causing gastric acid hypersecretion and multiple or recurrent peptic ulcers. Fasting gastrin must be interpreted with gastric pH and confounders such as proton-pump inhibitor use.
ZES causes gastric acid hypersecretion, recurrent ulcers and secretory diarrhoea.

4. Gastric and oesophageal cancer

Gastrinoma causes inappropriate gastrin secretion, marked gastric acid hypersecretion, recurrent ulcers and sometimes diarrhoea. Confirmation requires interpreting fasting gastrin with gastric pH and selected provocative tests while considering PPI effects.
An epigastric hernia is a primary midline defect of the linea alba between the umbilicus and xiphoid. A focal palpable fascial defect and cough impulse distinguish it from rectus diastasis, which is a broad separation of rectus muscles without a true focal hernia defect.
Autoimmune destruction of gastric oxyntic mucosa and/or intrinsic factor leads to impaired terminal ileal absorption of vitamin B12. Anti-intrinsic-factor antibody testing is the preferred initial specific test when autoimmune gastritis is suspected.
Ibuprofen inhibits COX-1 and COX-2, decreasing gastric prostaglandins that normally promote mucus and bicarbonate secretion and mucosal blood flow. Acid and pepsin can therefore injure the less-protected epithelium, producing erosions, ulceration and bleeding.
Pernicious anaemia is associated with autoimmune atrophic gastritis, intestinal metaplasia and increased gastric neoplasia risk. Progressive alarm symptoms and new microcytic iron-deficiency anaemia warrant prompt upper gastrointestinal endoscopy and biopsy.
Autoimmune atrophic gastritis in pernicious anaemia increases the risk of gastric neoplasia. New alarm symptoms with iron-deficiency anaemia and upper gastrointestinal bleeding require urgent upper endoscopy and biopsy to exclude gastric carcinoma.

5. Varices and portal hypertension

Beta-blockers reduce portal inflow and portal pressure; EVL eradicates endoscopically accessible varices.

Applied anatomy and pathology

Preganglionic parasympathetic fibres from S2–S4 travel via pelvic splanchnic nerves to the inferior hypogastric plexus and cavernous nerves. Nitric-oxide-mediated relaxation of cavernosal smooth muscle permits erection.
A direct hernia protrudes through weakened transversalis fascia in Hesselbach triangle, bounded laterally by inferior epigastric vessels, medially by rectus abdominis and inferiorly by the inguinal ligament.
A direct inguinal hernia protrudes through Hesselbach triangle, bounded medially by the lateral border of rectus abdominis, laterally by inferior epigastric vessels, and inferiorly by the inguinal ligament.

Clinical recognition and differential diagnosis

Spastic oesophageal motility disorders cause non-propulsive or premature contractions and intermittent chest pain or dysphagia. High-resolution manometry distinguishes distal oesophageal spasm, hypercontractile oesophagus and achalasia subtypes.
Squamous-cell carcinoma predominates in the cervical and upper thoracic oesophagus and is associated with tobacco, alcohol, caustic injury and achalasia. Adenocarcinoma is more typically distal and associated with Barrett metaplasia.
Ménétrier disease causes giant rugal folds and excessive gastric mucus production, with loss of plasma proteins into the stomach. Hypoalbuminaemia produces dependent oedema and may coexist with weight loss.

Investigations and diagnostic interpretation

An erect chest radiograph may demonstrate free subdiaphragmatic gas from a perforated hollow viscus and can be obtained rapidly. CT abdomen with IV contrast is more sensitive for detecting and localising perforation in stable patients and should be used appropriately.
CT is more sensitive than plain radiographs for small-volume pneumoperitoneum and can often localise the perforation and identify associated fluid or inflammatory changes. Resuscitation and urgent surgical assessment should not be delayed for imaging in an unstable patient.
The coeliac plexus conveys much of the visceral pain from the pancreas. NICE recommends considering EUS-guided or image-guided neurolytic coeliac plexus block when pancreatic cancer pain is inadequately controlled, opioid toxicity is troublesome or opioid requirements rise.
Chronic acid exposure can cause inflammation and fibrosis of the distal oesophagus, producing a fixed narrowing and progressive solid-food dysphagia. The patient still requires prompt upper gastrointestinal endoscopy and biopsy when appropriate to exclude malignancy.

Management and operative principles

Forceful retching can cause longitudinal mucosal lacerations at the gastro-oesophageal junction, resulting in haematemesis. Many Mallory–Weiss bleeds settle spontaneously, but significant or persistent bleeding may require urgent endoscopy and haemostasis.
Barrett oesophagus replaces normal distal oesophageal squamous epithelium with intestinal-type columnar metaplasia, creating a recognised pathway to dysplasia and adenocarcinoma. A new progressive obstructive symptom or weight loss warrants urgent evaluation.
Boerhaave syndrome is a full-thickness oesophageal perforation after a sudden rise in intraoesophageal pressure during retching. The combination of vomiting, severe chest pain and subcutaneous emphysema is the classic Mackler triad and requires urgent resuscitation and specialist assessment.
Candida oesophagitis requires systemic antifungal therapy because topical mouth preparations do not reliably treat oesophageal infection. Fluconazole is a standard first-line treatment when the isolate is susceptible and no contraindication exists.

Measurements, staging and thresholds

Meckel diverticulum is a persistent vitelline (omphalomesenteric) duct remnant arising from the antimesenteric border of the distal ileum, classically within about 60 cm (2 feet) of the ileocaecal valve.
Diagnosis requires endoscopic biopsy, then staging with cross-sectional imaging and appropriate endoscopic ultrasound/PET-CT.
Biopsy establishes histology; staging uses appropriate cross-sectional and endoscopic investigations.
Treatment is stage- and location-dependent and may include definitive chemoradiotherapy or surgery.

Common examiner traps

Do not misstate that a chest X-ray is universally superior to CT for perforated ulcer: the stem specifically says CT is not promptly available.
Mitral surgery can also cause conduction disturbances, but the added lateral ischaemic findings specifically implicate the circumflex.
Do not offer curative oesophagectomy for confirmed distant metastasis; stenting is palliation, not oncological cure.
Raynaud with dysphagia is not synonymous with achalasia; the LES pressure/relaxation pattern distinguishes them.
Do not delay definitive assessment because the patient is pregnant or because plain radiography is negative.

Rapid-recall exam pearls

Coeliac plexus block may provide short-lived relief in selected refractory chronic pancreatitis, but is not routine first-line therapy.
Painless, significant gastrointestinal bleeding in a toddler should prompt consideration of Meckel diverticulum.
Discrete linea alba defect above umbilicus = epigastric hernia; broad ridge without defect = rectus diastasis.
Metastatic obstructing oesophageal cancer with urgent dysphagia relief needed: consider self-expanding stent.
An erect chest film is a quick free-air screen if CT is delayed; a negative film never rules out perforation.

Oesophageal, gastric and upper GI

Overview. Upper-GI disorders are separated by mechanical dysphagia, reflux physiology, bleeding and malignant obstruction.

Topic map — key distinctions

Subtopic	Defining feature / key principle
Oesophageal symptoms	Dysphagia from achalasia is a motility disorder, not a fixed fibrotic stricture.

1. Oesophageal symptoms

Dysphagia from achalasia is a motility disorder, not a fixed fibrotic stricture.

Candida oesophagitis typically presents with odynophagia or dysphagia and white adherent mucosal plaques. Biopsy or brushings show yeast forms and pseudohyphae; antibiotics, immunosuppression and frailty increase risk. Systemic antifungal treatment is generally needed for oesophageal infection.

Clinical recognition and differential diagnosis

Consider diabetes, HIV, steroid use or other immunosuppression when clinically indicated.
Late dumping occurs later and is associated with postprandial hypoglycaemia.

Investigations and diagnostic interpretation

White plaques can be confirmed with brushings or biopsy when diagnosis is uncertain.
Endoscopic biopsy is important if malignancy is possible.

Measurements, staging and thresholds

The adult gastro-oesophageal junction is usually about 40 cm from the upper incisors, although body size and anatomical variation affect the exact measurement. Endoscopists record distances to lesions from the incisors to support localisation and treatment planning.
Rapid delivery of hyperosmolar gastric contents into the small bowel causes fluid shifts into the intestinal lumen, gut peptide release and vasomotor symptoms within 10–60 minutes of eating. Early dumping follows operations that impair gastric reservoir or pyloric control.
Barrett segment measurements use endoscopic landmarks and Prague C/M criteria.
Upper oesophageal sphincter is approximately 15 cm from incisors.

Common examiner traps

Do not dilate an unexplained postoperative narrowing without assessing for malignancy or leak.
Do not equate early dumping with insulin-mediated late hypoglycaemia.
Oral thrush may be absent despite oesophageal candidiasis.

Rapid-recall exam pearls

Within 60 minutes after gastric surgery = early dumping; 1–3 hours = late dumping.
Upper oesophageal sphincter ~15 cm; gastro-oesophageal junction ~40 cm.
White oesophageal plaques plus pseudohyphae indicate Candida.
Benign anastomotic stricture → endoscopic dilation first.

Small bowel and intestinal obstruction

Overview. Obstruction may be mechanical or functional; assessment prioritises bowel viability, hydration and features of strangulation.

Topic map — key distinctions

Subtopic	Defining feature / key principle
Causes and transition point	Complicated sigmoid diverticulitis is the leading cause of colovesical fistula because inflammation and local perforation can create adhesions and a communication with the adjacent bladder.
Clinical signs and imaging	Nasogastric decompression is considered for significant vomiting/distension.
Nonoperative versus operative treatment	Peritonitis, perforation, ischaemic bowel, sepsis or failed decompression; discuss options with colorectal surgery.
Short bowel and malabsorption	Severe short bowel with persistent malnutrition despite oral/enteral optimisation may require long-term PN.

1. Causes and transition point

Complicated sigmoid diverticulitis is the leading cause of colovesical fistula because inflammation and local perforation can create adhesions and a communication with the adjacent bladder.

Adhesions are a frequent cause of SBO after abdominal or pelvic surgery.
Adhesions are a common cause of SBO after prior intra-abdominal surgery.
Postoperative colicky pain, vomiting and central dilated loops suggest adhesional SBO; CT evaluates danger signs.
A prior caesarean scar does not prove adhesions, and missing source X-rays cannot be interpreted retrospectively.
Dilated central small-bowel loops with valvulae conniventes traversing the full bowel diameter support small-bowel obstruction. Previous pelvic surgery increases the likelihood of postoperative adhesions. CT is often required to establish the transition point and assess ischaemia when clinically indicated.
CT abdomen/pelvis with intravenous contrast usually demonstrates the level, likely cause and complications of small-bowel obstruction, including closed-loop configuration or reduced bowel-wall enhancement. Previous abdominal surgery makes adhesions a common cause.

2. Clinical signs and imaging

Nasogastric decompression is considered for significant vomiting/distension.
Postoperative colicky pain, vomiting and central dilated loops suggest adhesional SBO; CT evaluates danger signs.

3. Nonoperative versus operative treatment

Peritonitis, perforation, ischaemic bowel, sepsis or failed decompression; discuss options with colorectal surgery.

Do not attempt endoscopic decompression when perforation or peritonitis requires urgent surgery.

4. Short bowel and malabsorption

Severe short bowel with persistent malnutrition despite oral/enteral optimisation may require long-term PN.

Applied anatomy and pathology

The femoral ring is bounded anteriorly by the inguinal ligament, posteriorly by Cooper (pectineal) ligament, medially by lacunar ligament and laterally by the femoral vein. Narrow boundaries contribute to femoral hernia strangulation risk.
Branching smooth-muscle bundles extending through the lamina propria.
Beware an aberrant obturator artery near the lacunar ligament.

Clinical recognition and differential diagnosis

Peutz–Jeghers syndrome is an autosomal-dominant hamartomatous polyposis disorder associated with germline loss-of-function variants in STK11/LKB1. The polyps have arborising smooth-muscle cores and patients require tailored gastrointestinal and extraintestinal cancer surveillance.
Anaemia can reflect iron deficiency, B12 malabsorption or chronic inflammation.
Creeping fat and strictures are characteristic gross findings.

Investigations and diagnostic interpretation

Contrast-enhanced CT identifies dilated proximal bowel, the transition point and likely aetiology, and can show features suggesting closed-loop obstruction, mesenteric compromise or perforation. Plain abdominal films may show dilated loops but cannot reliably establish the cause or exclude ischaemia.
The inferior mesenteric artery usually originates from the anterior aorta at approximately L3 and gives the left colic, sigmoid and superior rectal branches. Selective angiography may localise a bleeding sigmoid branch for targeted embolisation.
Creeping fat (fat wrapping) is a characteristic gross pathological feature of Crohn disease, reflecting transmural inflammation and mesenteric adipose expansion around affected bowel.
Resuscitation and urgent surgical assessment; CT is often used to define complications in a stable patient.

Management and operative principles

NICE permits stenting or emergency surgery in selected acute left-sided obstruction; rectal tumour location affects suitability.
Peritonitis, strangulation, closed-loop obstruction or clinical deterioration require urgent surgical assessment.
Urgent assessment is required for peritonism, strangulation or closed-loop obstruction.
A tender obstructed femoral hernia requires urgent surgical assessment.

Measurements, staging and thresholds

A diverting stoma may bridge obstructing rectal cancer to staging and neoadjuvant therapy.

Common examiner traps

Do not assume all left-sided obstructions require immediate anterior resection; neither is a stoma automatically the best choice for every stable patient.
A prior caesarean scar does not prove adhesions, and missing source X-rays cannot be interpreted retrospectively.
The femoral nerve is outside the femoral sheath and is not the lateral border of the femoral ring.
Do not attempt endoscopic decompression when perforation or peritonitis requires urgent surgery.
Hypoalbuminaemia may reflect inflammation as well as malnutrition; it does not mandate TPN.

Rapid-recall exam pearls

For an obstructed locally advanced rectal cancer planned for neoadjuvant treatment, diversion can preserve the oncological sequence.
Postoperative colicky pain, vomiting and central dilated loops suggest adhesional SBO; CT evaluates danger signs.
Severe short bowel with persistent malnutrition despite oral/enteral optimisation may require long-term PN.
Iron deficiency with suspected coeliac disease: IgA tTG/total IgA, then duodenal biopsy when indicated.
Femoral ring boundaries: anterior inguinal, posterior pectineal, medial lacunar, lateral vein.

Genitourinary

Bladder cancer and haematuria

Overview. Visible haematuria must be investigated rather than attributed to infection without reassessment; urothelial cancer is staged by depth of invasion.

Topic map — key distinctions

Subtopic	Defining feature / key principle
Visible haematuria workup	Urothelial carcinoma of the renal pelvis or ureter often presents with haematuria and may produce an enhancing collecting-system filling defect on excretory-phase CT urography.
Urothelial tumour staging	Urothelial carcinoma of the renal pelvis or ureter often presents with haematuria and may produce an enhancing collecting-system filling defect on excretory-phase CT urography.

1. Visible haematuria workup

Urothelial carcinoma of the renal pelvis or ureter often presents with haematuria and may produce an enhancing collecting-system filling defect on excretory-phase CT urography. A negative cystoscopy does not exclude an upper-tract source; ureteroscopic assessment and selective cytology or biopsy may be needed for diagnosis and risk stratification.

A blow to a distended bladder can cause rupture, often intraperitoneal at the dome. Pain, haematuria and failure to retain urine in a palpable bladder raise suspicion; CT cystography is used to establish the diagnosis in stable patients.
Visible haematuria requires malignancy assessment irrespective of infection history.
Painless visible haematuria is a red flag for urinary-tract malignancy.
Visible haematuria warrants appropriate urological evaluation.
Gross haematuria is common but not universal.

2. Urothelial tumour staging

For appropriately selected localised distal ureteric urothelial carcinoma, segmental distal ureterectomy with negative margins and ureteroneocystostomy preserves renal function while removing the tumour. Risk stratification and long-term ureteroscopic and bladder surveillance remain essential.
Urothelial carcinoma is the predominant histological subtype of bladder cancer in many populations. Smoking is a major risk factor, and painless visible haematuria is a typical presentation.
Bladder SCC is uncommon in non-endemic settings where urothelial carcinoma predominates.
Bladder urothelial carcinoma risks include tobacco and aromatic amine exposure.
Upper-tract urothelial carcinoma (UTUC) arises in the renal pelvis or ureter.

Applied anatomy and pathology

Chronic S. haematobium infection causes persistent bladder-wall inflammation, squamous metaplasia and increased risk of squamous cell carcinoma. Histology is required to diagnose the actual tumour.
Spinal anaesthesia does not reliably suppress direct obturator nerve stimulation.
The obturator nerve arises from L2–L4 and supplies thigh adductors.

Clinical recognition and differential diagnosis

Occupational exposure to aromatic amines, historically encountered in dye and rubber industries, is a well-established risk factor for urothelial carcinoma. Visible haematuria requires prompt evaluation, and a suspicious bladder lesion needs cystoscopic tissue diagnosis.
Extraperitoneal rupture is more often associated with pelvic fracture.
Smoking is an important urothelial cancer risk factor.

Investigations and diagnostic interpretation

Retrograde urethrography outlines the anterior urethral lumen and delineates stricture site and length for operative planning. Cystoscopy can confirm and evaluate the lumen, while ultrasound urethrography may assess spongiofibrosis in specialist centres. Uroflowmetry alone does not define anatomy.
Urine cytology and diagnostic ureteroscopy with targeted biopsy may assist diagnosis and risk classification.
Uncomplicated extraperitoneal rupture is often managed with catheter drainage and follow-up imaging.
Retrograde CT cystography is preferred for a stable patient with suspected bladder rupture.

Management and operative principles

The obturator nerve passes close to the inferolateral bladder wall. Electrical current during lateral-wall TURBT can trigger adductor muscle contraction (the obturator jerk), risking bladder perforation. Regional obturator nerve blockade and anaesthetic/surgical precautions may reduce this risk.
Surgical repair and bladder drainage; selected uncomplicated extraperitoneal injuries may be managed with catheter drainage.
Contrast remains in perivesical tissues and uncomplicated injuries can often heal with catheter drainage.
Traumatic intraperitoneal bladder rupture generally requires primary repair.

Measurements, staging and thresholds

Radical nephroureterectomy with excision of the bladder cuff, tailored to stage and patient factors.
UTUC is classified by grade, focality, size, invasion and imaging features.
Muscle-invasive status is central to staging and treatment selection.
Cystoscopy with biopsy/resection establishes histology and stage.

Common examiner traps

Schistosomiasis is classically linked to squamous bladder cancer, not the usual smoking-associated urothelial type.
Low-grade biopsy alone does not exclude occult high-grade or invasive disease; full risk assessment matters.
Schistosomiasis favours bladder squamous carcinoma; aromatic amines favour urothelial carcinoma.
A normal bladder cystoscopy does not rule out urothelial carcinoma in the upper urinary tract.
Do not insert a urethral catheter blindly if signs of associated urethral injury are present.

Rapid-recall exam pearls

Bladder dome rupture with contrast between bowel loops = intraperitoneal injury requiring repair.
Obturator block prevents the adductor jerk during lateral-wall bladder tumour resection.
Haematuria + enhancing renal-pelvis filling defect = suspect UTUC, not parenchymal RCC.
A blow to a full bladder plus haematuria and no palpable distension suggests rupture.
Aromatic dye or rubber industry + haematuria = think bladder urothelial carcinoma.

Prostate and lower urinary tract

Overview. Lower urinary tract symptoms arise from obstruction, storage dysfunction or infection; prostate cancer evaluation is distinct from benign enlargement.

Topic map — key distinctions

Subtopic	Defining feature / key principle
BPH and retention	BPH is nodular hyperplasia of both stromal and epithelial components, usually in the transition zone around the prostatic urethra.
Prostate cancer pathway	Gleason grade group and PSA are key prognostic factors.
Procedures and complications	Non-palpable cancer identified by needle biopsy, commonly prompted by PSA, rather than incidental TURP tissue.
Prostate anatomy and physiology	The ejaculatory ducts traverse the prostate and open on either side of the prostatic utricle at the seminal colliculus in the prostatic urethra.

1. BPH and retention

BPH is nodular hyperplasia of both stromal and epithelial components, usually in the transition zone around the prostatic urethra. It is not merely an increase in individual cell size.

BPH can cause bladder outlet obstruction, retention and secondary upper-tract effects.
Fit BPH patient with recurrent retention: consider definitive outlet surgery such as HoLEP.
Evaluate PSA and malignancy risk separately; elevated PSA is not synonymous with BPH.
Adult acquired diverticula commonly accompany BPH or urethral obstruction.
BPH usually arises in the transition zone.
BPH = hyperplasia (more cells), not hypertrophy (bigger cells).

2. Prostate cancer pathway

Gleason grade group and PSA are key prognostic factors.
Non-palpable cancer identified by needle biopsy, commonly prompted by PSA, rather than incidental TURP tissue.
Biopsy decisions incorporate MRI, PSA density, clinical examination and patient preferences.
Evaluate PSA and malignancy risk separately; elevated PSA is not synonymous with BPH.
Consider repeat PSA and factors affecting PSA before referral as appropriate.
Consider PSA and prostate examination as clinically appropriate.

3. Procedures and complications

Non-palpable cancer identified by needle biopsy, commonly prompted by PSA, rather than incidental TURP tissue.

TURP remains a common surgical option in suitable glands.
Incidental, clinically inapparent prostate cancer identified in more than 5% of TURP tissue is classified as clinical T1b. T1a involves 5% or less of resected tissue. Stage alone does not determine treatment: PSA, grade group, life expectancy, comorbidity and further assessment are important.
Incidental prostate cancer in >5% of TURP chips = cT1b.
Do not equate TURP detection with T2 disease or assume that every T1b case needs radical surgery.

4. Prostate anatomy and physiology

The ejaculatory ducts traverse the prostate and open on either side of the prostatic utricle at the seminal colliculus in the prostatic urethra. They conduct sperm and seminal-vesicle secretions toward the urethra.

Prostate carcinoma often arises in the peripheral zone.
Ejaculatory ducts run through the prostate.
BPH is nodular hyperplasia of both stromal and epithelial components, usually in the transition zone around the prostatic urethra. It is not merely an increase in individual cell size.
BPH usually arises in the transition zone.

Applied anatomy and pathology

Metastatic hormone-sensitive prostate cancer is treated with systemic androgen suppression, generally combined with an androgen-receptor pathway inhibitor and/or chemotherapy according to disease volume and fitness. Local treatments may be adjunctive.
Pelvic fracture urethral injuries classically involve the posterior urethra near the membranous or prostatomembranous region due to displacement and shearing. This differs from straddle trauma, which more often injures the anterior bulbar urethra.
The inferior vesical artery usually arises from the anterior division of the internal iliac and supplies the male bladder base, prostate and seminal vesicles. Its female analogue is commonly the vaginal artery.

Clinical recognition and differential diagnosis

Prostate adenocarcinoma is classically associated with osteoblastic or sclerotic skeletal metastases, especially in the axial skeleton and proximal femur. Haematuria does not on its own determine the primary site.
Anterior spinal artery syndrome causes bilateral motor weakness and pain/temperature loss.
Motor function and pain/temperature; dorsal-column modalities are often spared.

Investigations and diagnostic interpretation

Painless visible haematuria in an older smoker is a red-flag presentation for urothelial carcinoma. Appropriate evaluation includes cystoscopy and upper-tract imaging according to the haematuria pathway.
MRI is not a substitute for urgent evaluation of possible metastatic spinal cord compression if neurological red flags are present.
Nitrites suggest nitrate-reducing organisms such as Enterobacterales, but a negative nitrite test does not exclude UTI.
A discussion of targeted biopsy, often with additional systematic/perilesional sampling according to the pathway.

Management and operative principles

The artery of Adamkiewicz is a major radiculomedullary feeder of the anterior spinal artery, usually arising from a left lower thoracic or upper lumbar segmental artery. Injury during thoracoabdominal aortic surgery can compromise anterior spinal cord perfusion.
Radiotherapy may complement fixation but does not immediately restore mechanical stability.
Spinal cord protection during complex aortic repair is a major perioperative priority.
Acute retention requires prompt bladder drainage.

Measurements, staging and thresholds

A Mirels score of 9 or more indicates substantial risk of impending pathological fracture and generally prompts consideration of prophylactic fixation, accounting for prognosis, lesion anatomy and overall oncological plan.
Prostatic lymphatics drain primarily to pelvic nodes including obturator and internal iliac groups, with additional routes to external iliac and presacral nodes. These basins are considered in pelvic nodal staging.
A Gleason score of 9 belongs to Grade Group 5 and is histologically higher grade than scores 6 or 7. Pattern 4 predominates and pattern 5 is also present, indicating poorly differentiated architecture.
Score ≤7: usually lower fracture risk; 8: clinical judgement; ≥9: consider prophylactic fixation.

Common examiner traps

Do not assume that haematuria automatically means renal or bladder cancer when the radiological metastasis pattern is characteristic.
Do not attribute every postoperative retention episode to diabetic neuropathy without checking reversible factors and obstruction.
Postoperative retention is multifactorial; do not attribute all cases to diabetic neuropathy without excluding obstruction.
Do not assume the diverticulum is the primary cause when outlet obstruction drives both the residual urine and pouch.
Do not equate TURP detection with T2 disease or assume that every T1b case needs radical surgery.

Rapid-recall exam pearls

Haematuria with dysuria and E. coli culture points to cystitis; do not ignore persistent post-treatment haematuria.
Thoracoabdominal aortic repair + paraplegia = consider Adamkiewicz/anterior spinal cord ischaemia.
A demonstrable fixed narrowing distinguishes urethral stricture from functional voiding disorders.
Painless visible haematuria in an older smoker is bladder cancer until adequately investigated.
Fit BPH patient with recurrent retention: consider definitive outlet surgery such as HoLEP.

Renal and ureteric calculi

Overview. Stone management balances pain and obstruction against infection, renal function, size and anatomical location.

Topic map — key distinctions

Subtopic	Defining feature / key principle
Stone composition and risks	Uric acid stones form in persistently acidic urine and are often radiolucent on plain radiography, although visible on noncontrast CT.
Imaging and localisation	Uric acid stones form in persistently acidic urine and are often radiolucent on plain radiography, although visible on noncontrast CT.
Medical versus procedural treatment	Shock-wave lithotripsy can fragment appropriately selected renal calculi, particularly smaller stones in favourable anatomical and density settings.
Infected obstructed system	Sepsis with an obstructed kidney is a urological emergency requiring urgent decompression and antimicrobial therapy.

1. Stone composition and risks

Uric acid stones form in persistently acidic urine and are often radiolucent on plain radiography, although visible on noncontrast CT. Alkalinising urine with potassium citrate or another appropriate alkali can dissolve uric acid stones; urine pH must be monitored to avoid over-alkalinisation and calcium-phosphate precipitation.

Calcium phosphate and struvite stones are also generally radiopaque.
Calcium oxalate is the commonest urinary stone composition and is generally radiopaque. CT is highly sensitive for urinary calculi, while plain KUB may show calcium-containing stones. Uric acid stones are usually radiolucent on plain films.
Most renal stones contain calcium salts, especially calcium oxalate, formed when urinary supersaturation exceeds inhibitory mechanisms. Composition guides prevention and sometimes imaging or intervention.
Urinary citrate inhibits calcium stone formation.
Radiopaque urinary calculus: calcium-containing stone is most likely.
Most renal stones overall are calcium oxalate; the bacterium and urine pH alter the best answer in this vignette.

2. Imaging and localisation

Uric acid stones are usually radiolucent on plain KUB but seen on noncontrast CT.
Radiolucent on plain X-ray does not mean invisible on noncontrast CT.

3. Medical versus procedural treatment

Shock-wave lithotripsy can fragment appropriately selected renal calculi, particularly smaller stones in favourable anatomical and density settings. Choice between SWL and flexible ureteroscopy depends on stone and patient characteristics and shared decision-making.

For a symptomatic distal ureteric stone requiring intervention, ureteroscopy provides direct access, fragmentation and removal, often with a higher immediate stone-free rate than shock-wave lithotripsy. The decision is individualised and depends on anatomy and patient preference.

4. Infected obstructed system

Sepsis with an obstructed kidney is a urological emergency requiring urgent decompression and antimicrobial therapy. Nephrostomy or retrograde ureteric stenting are both accepted drainage approaches; the original source provided nephrostomy among the options.

Sepsis with an obstructing stone requires urgent drainage and antibiotics, not medical expulsive therapy alone.
Obstruction with sepsis requires urgent drainage and antibiotics before definitive stone removal.
Do not perform routine definitive stone fragmentation during uncontrolled sepsis.
With infection/sepsis, anuria, threatened renal function or uncontrolled pain.
Treat hypotension and organ dysfunction according to sepsis protocols.
Definitive stone treatment is delayed until sepsis resolves.

Applied anatomy and pathology

The genitofemoral nerve contributes to perceived groin/scrotal referral.

Clinical recognition and differential diagnosis

Visceral afferent fibres from the ureter travel with sympathetic pathways to lower thoracic and upper lumbar spinal segments, classically T11–L2. Convergence with somatic afferents explains referred pain from loin to groin and external genitalia.
Infection, refractory pain, persistent obstruction, declining renal function or patient preference for definitive treatment.
Persistent obstruction, renal impairment or uncontrolled pain favours active intervention.

Investigations and diagnostic interpretation

Cystoscopy directly evaluates bladder mucosa, while CT urography evaluates the kidneys, renal pelvis and ureters when appropriate for haematuria work-up. A noncontrast stone CT cannot replace urothelial phase imaging, and no single test substitutes for the other when both upper and lower tracts require assessment.
Ultrasound avoids ionising radiation and is the preferred first imaging test for suspected renal stones during pregnancy. It can assess hydronephrosis, renal calculi and sometimes ureteric jets; additional imaging is reserved for unresolved cases.
Individualise with renal ultrasound, MR urography or retrograde studies according to specialist assessment.
Consider non-contrast MRI/MR urography or carefully justified low-dose CT depending on urgency.

Management and operative principles

An infected obstructed kidney is a urological emergency. Both retrograde ureteric stenting and percutaneous nephrostomy are effective means of urgent source control; immediate antimicrobials and haemodynamic support accompany drainage. Definitive stone removal follows control of sepsis.
Diffuse xanthogranulomatous pyelonephritis destroys functioning renal parenchyma and often mimics renal cancer. A chronically infected, poorly functioning kidney with extensive XGP generally requires nephrectomy after antimicrobial treatment and any necessary drainage.
A small distal ureteric stone has a high probability of spontaneous passage when pain is controlled and there is no infection, renal failure or persistent obstruction. Conservative management includes analgesia, safety-netting and follow-up to confirm resolution.
Intermittent pelvi-ureteric junction obstruction can produce Dietl crisis: flank pain precipitated by diuresis as urine production temporarily exceeds drainage through a narrowed PUJ. Functional confirmation is by diuretic renography.

Measurements, staging and thresholds

Observation requires analgesia, safety-netting and interval imaging to document passage or persistent obstruction.
Distal ureteric stones over 5 mm may be offered an alpha blocker when observation is appropriate.
The benefit of alpha blockers is most apparent in distal ureteric stones larger than 5 mm.
Distal stones 5–10 mm may benefit from alpha-blocker MET if observation is safe.

Common examiner traps

Absence of hydronephrosis alone does not prove that a 10-mm ureteric stone will pass spontaneously; avoid making stone size the sole determinant.
A ureteric stent is also a correct drainage method; the chosen answer depends on the available choices and clinical setting.
Do not proceed directly to elective nephrectomy in an unstable septic patient without resuscitation and source control.
Most renal stones overall are calcium oxalate; the bacterium and urine pH alter the best answer in this vignette.
Do not confuse physiological hydronephrosis with an obstructing stone without clinical correlation.

Rapid-recall exam pearls

Symptomatic distal ureteric stone about 10 mm: URS is a strong definitive option; sepsis changes priority to drainage.
Persistent symptomatic distal stone: URS is a common definitive option; infected obstruction: decompress first.
Stable distal 5–10-mm stone: discuss off-label alpha-blocker MET; infected obstruction: drain urgently.
Urease-positive UTI + alkaline urine + branching calculus = struvite until proven otherwise.
Infected obstruction + failed stent → urgent nephrostomy, not immediate lithotripsy.

Renal masses and kidney disease

Overview. Renal masses are characterised by enhancement and anatomical extent; renal function and systemic features alter the management approach.

Topic map — key distinctions

Subtopic	Defining feature / key principle
RCC and presenting features	Renal cell carcinoma can produce ectopic erythropoietin, causing secondary erythrocytosis.
Renal imaging and biopsy	Renal ultrasonography is a non-invasive, radiation-free way to reassess collecting-system dilatation after treatment of obstruction.
Kidney function and syndromes	Obstructive renal failure may need urgent decompression by stenting or nephrostomy.

1. RCC and presenting features

Renal cell carcinoma can produce ectopic erythropoietin, causing secondary erythrocytosis. Painless haematuria, weight loss and a solid renal parenchymal mass are compatible with RCC.

Renal cell carcinoma is the commonest malignant solid renal parenchymal tumour in adults and may present with painless haematuria, flank pain or an incidentally detected renal mass. Contrast-enhanced multiphasic imaging characterises local extension and venous involvement.
RCC may present with haematuria and can spread haematogenously to lung and bone. Its skeletal metastases are often lytic and may cause pathological fracture or spinal instability.
Classic RCC may present with haematuria, flank pain or a mass, but the full triad is uncommon.
An enhancing solid renal cortical mass in an older patient with haematuria is highly suspicious for renal cell carcinoma. Contrast-enhanced cross-sectional imaging characterises the lesion and helps stage the disease; histology is established when tissue is sampled or resected, not by ultrasound alone.
Enhancing solid renal cortical mass plus visible haematuria: suspect RCC.

2. Renal imaging and biopsy

Renal ultrasonography is a non-invasive, radiation-free way to reassess collecting-system dilatation after treatment of obstruction. It can document residual hydronephrosis and renal size. If obstruction remains suspected despite equivocal ultrasound, further functional or cross-sectional imaging may be needed; a nephrostogram is appropriate for selected patients while a nephrostomy remains in place.

Renal cell carcinoma is the commonest malignant solid renal parenchymal tumour in adults and may present with painless haematuria, flank pain or an incidentally detected renal mass. Contrast-enhanced multiphasic imaging characterises local extension and venous involvement.
Cigarette smoking increases renal cell carcinoma risk, with a dose-related association; obesity and hypertension are also recognised modifiable risk factors. A solid enhancing renal cortical mass needs appropriate urological imaging and assessment regardless of smoking history.
Renal cell carcinoma can produce ectopic erythropoietin, causing secondary erythrocytosis. Painless haematuria, weight loss and a solid renal parenchymal mass are compatible with RCC.
High-pressure chronic retention occurs when sustained bladder outlet obstruction raises intravesical pressure enough to transmit back-pressure to the ureters and kidneys. Large residual volume, bilateral upper-tract dilatation and renal impairment are important clues.

3. Kidney function and syndromes

Obstructive renal failure may need urgent decompression by stenting or nephrostomy.

Applied anatomy and pathology

An indeterminate solid renal lesion needs urology multidisciplinary assessment.

Clinical recognition and differential diagnosis

The classical triad of haematuria, flank pain and mass is uncommon and often late.
Wilms tumour commonly presents as a painless abdominal mass in early childhood.
Classic triad of haematuria, pain and palpable mass is uncommon.

Investigations and diagnostic interpretation

Biopsy is considered when it would change management, especially before ablation or systemic treatment.
Enhancing intraluminal soft tissue contiguous with the renal tumour, evaluated on contrast CT or MRI.
Indeterminate CT findings, suspected venous thrombus or need to avoid iodinated contrast.
Contrast-enhanced CT assesses enhancement, renal vein involvement and regional disease.

Management and operative principles

External-beam radiotherapy can provide meaningful analgesia from painful bone metastases and may reduce local tumour activity. Orthopaedic assessment remains important to identify impending fracture, for which prophylactic fixation may be necessary before or with radiotherapy.
Treatment may combine surgery/stabilization, stereotactic radiotherapy and systemic therapy according to extent and prognosis.
Spinal metastases with neurological deficits require urgent assessment for cord compression.
Fever or recurrent flank pain after drainage warrants urgent reassessment.

Measurements, staging and thresholds

Multiphasic contrast-enhanced CT evaluates enhancement, local extent, venous involvement and regional spread of a suspicious solid renal tumour. Chest imaging for staging is determined by clinical stage and risk; MRI can be useful when contrast CT is unsuitable or venous involvement is uncertain.
Prostate adenocarcinoma can obstruct the bladder outlet or ureters and characteristically metastasises to the axial skeleton with predominantly osteoblastic/sclerotic lesions. Tissue diagnosis and staging are needed; PSA alone does not establish or exclude cancer.
Ultrasound is a rapid, non-ionising first-line test to establish whether a paediatric abdominal mass is renal, cystic or solid, and to assess the contralateral kidney before specialist staging.
Ultrasound is the initial modality; cross-sectional staging follows specialist pathways.

Common examiner traps

Do not select radiotherapy or fixation from one radiograph without considering fracture risk, disease burden and multidisciplinary planning.
If the nephrostomy is still in situ and ureteric patency is the question, an antegrade nephrostogram may be more informative.
Do not infer that a smoker with haematuria must have RCC; urothelial cancer also requires evaluation.
A solid lesion on ultrasound is not histological proof of RCC; benign oncocytoma can mimic it.
Do not assume all patients with RCC are anaemic; paraneoplastic erythrocytosis is possible.

Rapid-recall exam pearls

Obstructive urinary symptoms plus sclerotic bone lesions suggest metastatic prostate cancer.
A single painful bone lesion on radiograph is not fully staged solitary metastatic disease.
Ultrasound-detected suspicious solid renal mass → contrast-enhanced renal-protocol CT.
Large painless retention + bilateral hydronephrosis = high-pressure chronic retention.
Enhancing solid renal cortical mass plus visible haematuria: suspect RCC.

Renal, transplant and urological disorders

Overview. Kidney and transplant-related problems are interpreted through vascular anatomy, graft function, immunosuppression and urinary tract obstruction.

Topic map — key distinctions

Subtopic	Defining feature / key principle
Transplant graft assessment	HLA-DR is an HLA class II antigen historically weighted strongly in renal transplant matching because mismatches can increase allorecognition and rejection risk.
Renal and urological emergencies	HLA-DR is an HLA class II antigen historically weighted strongly in renal transplant matching because mismatches can increase allorecognition and rejection risk.

1. Transplant graft assessment

HLA-DR is an HLA class II antigen historically weighted strongly in renal transplant matching because mismatches can increase allorecognition and rejection risk. Contemporary allocation also evaluates HLA-A/B/DR/DQ, donor-specific antibodies, crossmatch and clinical urgency.

Positive donor-specific T-cell CDC crossmatch is a red flag for hyperacute graft rejection.
Some positive flow or isolated B-cell crossmatches require nuanced transplant-team assessment.
Classic renal transplant recall: HLA-DR is an important class II matching locus.
Post-transplant fever + leukopenia: consider CMV and test quantitative CMV DNA.

2. Renal and urological emergencies

Technetium-99m MAG3 renography measures relative renal function and drainage curves, commonly with diuretic challenge, helping distinguish functionally significant pelvi-ureteric junction obstruction from non-obstructive dilatation.
Long-term haemodialysis can lead to beta-2 microglobulin accumulation and amyloid deposition in osteoarticular tissues, producing carpal tunnel syndrome, arthropathy and bone cysts. The original recall merely said renal failure and omitted the relevant dialysis history and beta-2 microglobulin option; those discriminators were added.
Urine contacting ileal or colonic mucosa allows exchange of ammonium and chloride into the blood and bicarbonate loss, producing a normal-anion-gap hyperchloraemic metabolic acidosis, especially with impaired renal clearance.
A mobile or ptotic kidney can descend into the lower abdomen and be ballotable and respiratory-mobile. Its renal contour and mobility help distinguish it from a fixed inflammatory or bowel mass; imaging confirms anatomy.
Valganciclovir or IV ganciclovir are used for treatment according to disease severity and renal function.

Applied anatomy and pathology

ADH increases collecting-duct water permeability via aquaporin-2.

Clinical recognition and differential diagnosis

Idiopathic hypercalciuria describes excessive urinary calcium excretion in a patient without hypercalcaemia or another identifiable systemic cause. It is a common metabolic risk factor for recurrent calcium-containing stones.
The kidney is usually ballotable without a splenic notch; splenic enlargement has a characteristic notch and direction of enlargement.
CMV can cause fever, cytopenias, hepatitis, colitis and graft dysfunction.

Investigations and diagnostic interpretation

Ischaemic blood is dark, hypoxic, hypercapnic and acidotic; non-ischaemic blood is closer to arterial values.
Assess 24-hour urine volume, pH, calcium, oxalate, citrate, uric acid, sodium, potassium and creatinine.
A negative crossmatch is essential to assess unacceptable donor-specific antibody risk.
Ultrasound or cross-sectional imaging confirms position and vascular anatomy.

Measurements, staging and thresholds

Net filtration pressure = (glomerular capillary hydrostatic pressure + Bowman-space oncotic pressure) − (Bowman-space hydrostatic pressure + glomerular capillary oncotic pressure). Thus (45 + 0) − (10 + 27) = 8 mmHg.

Common examiner traps

Positive PCR alone does not always establish tissue-invasive CMV disease; clinical context and tissue biopsy may be needed.
A calcium oxalate stone alone does not establish hypercalciuria; urine data were added to make the question answerable.
Do not claim HLA-DR is the only relevant locus or that matching substitutes for a negative crossmatch.
Do not equate HLA matching with a negative crossmatch; both answer different questions.
Do not equate every amyloid deposit in a patient with kidney failure with AA amyloid.

Rapid-recall exam pearls

High urine calcium + normal serum calcium/PTH = idiopathic hypercalciuria after excluding secondary causes.
Childhood-onset recurrent calcium-oxalate stones with marked hyperoxaluria suggest a metabolic disorder.
Recurrent calcium oxalate stones with normal serum calcium still require a 24-hour urine risk profile.
Long-term dialysis plus carpal tunnel syndrome and bone cysts = beta-2 microglobulin amyloid.
Positive donor-specific T-cell CDC crossmatch is a red flag for hyperacute graft rejection.

Testicular and scrotal conditions

Overview. Acute scrotal pain is torsion until confidently excluded; painless testicular swelling requires urgent characterisation for malignancy.

Topic map — key distinctions

Subtopic	Defining feature / key principle
Torsion and bell-clapper	Bell-clapper deformity describes abnormally extensive tunica-vaginalis investment and deficient posterior fixation, allowing the testis to rotate freely around the spermatic cord within the vaginal sac.
Epididymo-orchitis and infection	Acute epididymitis commonly presents with scrotal pain, swelling and tenderness, sometimes accompanied by fever and urinary symptoms.
Testicular tumour workup	AFP has a serum half-life of about five to seven days, so a fall by roughly half in six days is biologically appropriate.
Hydrocele, varicocele and hernia	A noncommunicating hydrocele is fluid within the tunica vaginalis without an open connection to the peritoneal cavity.
Scrotal trauma	Bell-clapper deformity describes abnormally extensive tunica-vaginalis investment and deficient posterior fixation, allowing the testis to rotate freely around the spermatic cord within the vaginal sac.

1. Torsion and bell-clapper

Bell-clapper deformity describes abnormally extensive tunica-vaginalis investment and deficient posterior fixation, allowing the testis to rotate freely around the spermatic cord within the vaginal sac. This predisposes to intravaginal torsion, often with transverse lie. A high-riding painful testis remains a surgical emergency and must not be dismissed because trauma preceded the symptoms.

Preserved cremasteric reflex lowers suspicion but cannot independently exclude testicular torsion.
Sudden severe pain, vomiting, high lie and absent cremasteric reflex increase torsion suspicion.
Sudden severe pain, nausea, high-riding testis and absent cremasteric reflex support torsion.
A preserved cremasteric reflex does not absolutely exclude torsion.
Do not use a positive cremasteric reflex or Doppler alone to dismiss possible spermatic-cord torsion.
The appendix testis is a vestigial Müllerian remnant at the superior testicular pole. Torsion produces focal tenderness and occasionally a visible blue-dot sign, with preserved perfusion of the testis itself. If testicular torsion remains clinically possible, urgent surgical assessment must not be delayed by reassuring isolated signs.

2. Epididymo-orchitis and infection

Acute epididymitis commonly presents with scrotal pain, swelling and tenderness, sometimes accompanied by fever and urinary symptoms. Evaluation includes exclusion of torsion and tests for likely urinary or sexually transmitted pathogens.

An epididymal cyst is a benign fluid-filled extratesticular lesion, often arising in the head of the epididymis. Its separation from the testis and cystic appearance on ultrasound distinguish it from a solid intratesticular tumour. Symptomatic or enlarging lesions can be considered for specialist treatment.
Spermatoceles may contain sperm and often arise in the epididymal head.
Gradual tender epididymis + dysuria/fever → epididymitis, but exclude torsion.
A separate, cystic epididymal-head mass is usually benign.
When torsion is not clinically obvious and ultrasound is immediately available, Doppler can assess intratesticular perfusion and epididymal hyperaemia. Clinical suspicion still governs action: imaging must not delay exploration when torsion is strongly suspected.

3. Testicular tumour workup

AFP has a serum half-life of about five to seven days, so a fall by roughly half in six days is biologically appropriate. Serial postoperative AFP and beta-hCG trends are essential to stage disease and identify persistent tumour; an appropriate early decline alone cannot exclude metastasis. AFP elevation also argues against pure seminoma.

Obtain AFP, beta-hCG and LDH before orchidectomy when germ-cell tumour is suspected.
Pure seminoma does not produce AFP, although beta-hCG can be elevated.
Measure AFP, beta-hCG and LDH before orchidectomy when feasible.
Measure AFP, beta-hCG and LDH before orchidectomy.
AFP, beta-hCG and LDH; their levels aid diagnosis, staging and monitoring but do not alone establish histological subtype.
AFP half-life is about 5–7 days; beta-hCG about 1–3 days.

4. Hydrocele, varicocele and hernia

A noncommunicating hydrocele is fluid within the tunica vaginalis without an open connection to the peritoneal cavity. It is typically painless, cystic, transilluminating and nonreducible, with little variation in size. Examination and ultrasound are used when the testis is not adequately assessed or findings are atypical.

A patent processus vaginalis underlies both communicating hydroceles and indirect hernias.
A communicating hydrocele transmits fluid; a hernia may contain bowel and carries an incarceration risk.
Do not mistake hydrocele, which transilluminates, for a varicocele.
A hydrocele is fluid between layers of the tunica vaginalis, producing a fluctuant transilluminant swelling surrounding the testis.
Noncommunicating hydroceles do not have a peritoneal connection and do not typically vary during the day.
Treatment depends on symptoms, cause and size; surgery is considered for bothersome persistent hydrocele.

5. Scrotal trauma

Minor trauma often draws attention to a pre-existing testicular tumour rather than causing it.
Testicular trauma may draw attention to an existing tumour; it does not prove benign injury.
A high-riding transverse testis after minor trauma can still represent spermatic cord torsion.
A history of blunt trauma does not establish hematocele; do not allow it to override high-risk torsion signs.

Applied anatomy and pathology

The left gonadal vein typically drains at a right angle into the left renal vein, contributing to the increased frequency of left-sided varicoceles. The right gonadal vein usually enters the inferior vena cava directly.
Scrotal skin drains mainly to the superficial inguinal lymph nodes, unlike testicular tissue, which drains to retroperitoneal para-aortic/interaortocaval nodes.
The left testicular vein drains into the left renal vein, with different venous geometry and pressure.

Clinical recognition and differential diagnosis

A patent processus vaginalis allows abdominal contents to pass through the deep inguinal ring into the canal or scrotum. Intermittent swelling with crying and reducibility strongly suggests an indirect inguinal hernia.
A similar predisposition may be present in the other testis, putting it at risk of subsequent torsion.
A transverse lie, absent cremasteric reflex and sudden severe pain increase clinical suspicion.

Investigations and diagnostic interpretation

Sperm extravasation from the cut or disrupted vas can provoke a local foreign-body granulomatous reaction. It may produce a tender palpable nodule and contribute to post-vasectomy pain. Ultrasound and examination help exclude a testicular mass or other pathology.
A typical primary varicocele usually decreases in size when supine. A sudden-onset or non-decompressing varicocele warrants consideration of secondary venous obstruction, including renal or retroperitoneal pathology, although malignancy is uncommon and evaluation should be individualised.
Choriocarcinoma contains malignant trophoblastic elements that secrete very large amounts of beta-hCG and spread early through blood vessels, producing haemorrhagic metastases, particularly in the lungs. This histological description makes the diagnosis specific; the original isolated high beta-hCG value did not.
Testicular torsion is time-critical ischaemia from twisting of the spermatic cord. A strongly suggestive clinical presentation warrants immediate operative assessment and exploration without delaying for imaging.

Management and operative principles

Testicular torsion twists the spermatic cord, threatening arterial inflow and venous drainage. When clinical suspicion is high, immediate surgical exploration and detorsion are required; the opposite testis is ordinarily fixed because of shared predisposition.
Torsion of an undescended testis is a time-critical surgical emergency. Sudden pain, an empty hemiscrotum and a tender inguinal testis require urgent exploration and detorsion or orchidectomy according to viability, with fixation of the contralateral testis.
A varicocele is abnormal dilatation of the pampiniform venous plexus draining to the testicular vein. Left-sided predominance reflects drainage of the left testicular vein into the left renal vein.
Left gonadal drainage joins the left renal vein at a right angle and can be affected by increased renal-vein pressure.

Measurements, staging and thresholds

Clinical management requires urgent specialist staging and systemic therapy; do not perform trans-scrotal testicular biopsy.
Tumour staging also requires appropriate imaging and pathology review.
Assess retroperitoneal nodes in staging imaging.

Common examiner traps

A history of blunt trauma does not establish hematocele; do not allow it to override high-risk torsion signs.
Never allow a large hydrocele to conceal a testicular tumour; ultrasound when examination is inadequate.
A communicating hydrocele transmits fluid; a hernia may contain bowel and carries an incarceration risk.
Transillumination does not rule out an underlying testicular mass; ensure the testis can be assessed.
Do not use a positive cremasteric reflex or Doppler alone to dismiss possible spermatic-cord torsion.

Rapid-recall exam pearls

Transilluminating, nonreducible, nonfluctuating scrotal fluid collection suggests noncommunicating hydrocele.
A reducible swelling that enlarges with crying in a young boy suggests indirect inguinal hernia.
A solid intratesticular mass requires urgent ultrasound, tumour markers and urological referral.
A high-riding transverse testis after minor trauma can still represent spermatic cord torsion.
A varicocele that fails to decompress supine deserves assessment for secondary obstruction.

Urethra, penile and genital injury

Overview. Genitourinary trauma is localised by injury mechanism, bleeding at the meatus, voiding dysfunction and appropriate contrast imaging.

Topic map — key distinctions

Subtopic	Defining feature / key principle
Urethral injury	The urinary bladder and urethra lie anterior to the vagina.
Stricture	Chronic urethritis followed by weak stream → urethral stricture.
Catheter considerations	A full bladder despite an indwelling catheter points to drainage failure rather than true renal anuria.

1. Urethral injury

The urinary bladder and urethra lie anterior to the vagina. The bladder base is related to the anterior vaginal wall, while the uterus and cervix are superior/posterior relations depending on level.

An isolated straddle injury compresses the anterior bulbar urethra against the inferior pubic arch. Blood at the meatus warrants urethral evaluation, generally retrograde urethrography in a stable patient, before blind catheterisation. Pelvic fracture more often injures the posterior bulbomembranous region.
Straddle injury = bulbar urethra; pelvic fracture = posterior urethra.
Hypospadias is a congenital ventral displacement of the urethral meatus, often associated with chordee and a dorsal preputial hood. Definitive repair may involve urethroplasty and correction of curvature. The foreskin should be preserved until specialist assessment because it may be useful in reconstruction.
Lymphatics from the glans and distal penile urethra drain to deep inguinal nodes (including the node of Cloquet), with further drainage to pelvic nodes. Penile skin primarily drains to superficial inguinal nodes.
Repeated urethral inflammation can heal by fibrosis, narrowing the urethral lumen. Patients develop a weak stream, straining, spraying and sometimes recurrent urinary infection or retention.

2. Stricture

Chronic urethritis followed by weak stream → urethral stricture.

3. Catheter considerations

A full bladder despite an indwelling catheter points to drainage failure rather than true renal anuria. The first step is to correct an external kink and assess patency; persistent blockage may require catheter replacement with appropriate technique.

Blood at the meatus is a key warning sign; do not blindly catheterise.
No catheter output plus a distended bladder = assess catheter patency first.
An isolated straddle injury compresses the anterior bulbar urethra against the inferior pubic arch. Blood at the meatus warrants urethral evaluation, generally retrograde urethrography in a stable patient, before blind catheterisation. Pelvic fracture more often injures the posterior bulbomembranous region.

Applied anatomy and pathology

Parasympathetic fibres from S2–S4 activate M3 muscarinic receptors on detrusor smooth muscle, promoting contraction during voiding. Relaxation of the urethral outlet requires coordinated autonomic and somatic control.
A dorsally placed urethral meatus defines epispadias, part of the exstrophy–epispadias spectrum. More severe forms involve an open anterior bladder and lower abdominal wall defect.
Both ureters enter the posterior bladder wall obliquely and open at the superolateral angles of the trigone. The internal urethral orifice forms the inferior angle.

Clinical recognition and differential diagnosis

Ventral curvature of the penis, often associated with hypospadias.

Investigations and diagnostic interpretation

The overwhelming majority of invasive penile cancers are squamous-cell carcinomas. Chronic phimosis and certain HPV infections are risk factors. A persistent ulcerated or fungating glans lesion requires urgent specialist assessment and tissue biopsy; inguinal nodes may be reactive or metastatic.
A safely localised, distended bladder is essential for blind percutaneous suprapubic access. A collapsed bladder does not displace intervening bowel away from the puncture tract, increasing the risk of bowel perforation. The proposed route must be deferred and specialist image-guided or alternative drainage arranged.
Confirm a sufficiently distended bladder clinically and with ultrasound before percutaneous insertion.
Ultrasound may identify bladder position and, with suitable expertise, interposed bowel.

Management and operative principles

Previous lower abdominal surgery, pelvic irradiation, coagulopathy and bladder tumour require special caution or may contraindicate routine insertion.
Glans: deep inguinal drainage; penile skin: superficial inguinal drainage.
Check the entire drainage system before diagnosing acute kidney injury.
Repair timing and technique depend on anatomy and specialist planning.

Measurements, staging and thresholds

Treatment is stage-dependent and aims to preserve function when oncologically safe.
Clinical examination and appropriate nodal staging are essential.

Common examiner traps

Prior abdominal surgery is an important relative risk factor; the clearest absolute problem in this vignette is a collapsed bladder with bowel in the planned tract.
Do not confuse urinary frequency from infection with the progressive obstructive pattern of stricture.
Palpable inguinal nodes are not automatically metastatic; inflammatory enlargement can coexist.
Do not confuse the bladder base with its dome, which is more superior and peritoneum-related.
Do not perform routine circumcision before hypospadias assessment.

Rapid-recall exam pearls

Never attempt blind suprapubic puncture when the bladder is not safely localised and distended.
Ventral penile meatus = hypospadias; preserve foreskin pending specialist review.
Persistent glans ulcer or fungating lesion in an older man = exclude penile SCC.
Penile glans is not the same as scrotal skin or testis for lymphatic drainage.
No catheter output plus a distended bladder = assess catheter patency first.

Urinary tract infection and emergencies

Overview. The inherited records currently assigned to this subsection chiefly concern perioperative urology and pregnancy-associated thromboembolism; they do not establish a complete UTI teaching chapter.

Topic map — key distinctions

Subtopic	Defining feature / key principle
TURP irrigation-fluid syndrome	During monopolar TURP, systemic absorption of non-electrolyte irrigation fluid can cause dilutional hyponatraemia, fluid overload and neurological symptoms.
Pregnancy-related venous thromboembolism	For confirmed acute pulmonary embolism in a haemodynamically stable pregnant patient, therapeutic low-molecular-weight heparin is the preferred anticoagulant.
Immediate assessment	Recognise nausea, confusion, visual disturbance and seizures.

1. TURP irrigation-fluid syndrome

During monopolar TURP, systemic absorption of non-electrolyte irrigation fluid can cause dilutional hyponatraemia, fluid overload and neurological symptoms. Bipolar saline-based systems greatly reduce this classic risk.

Not every TURP patient has the same risk; irrigation system and fluids matter.
Confusion and low sodium after TURP → consider TURP syndrome.

2. Pregnancy-related venous thromboembolism

For confirmed acute pulmonary embolism in a haemodynamically stable pregnant patient, therapeutic low-molecular-weight heparin is the preferred anticoagulant. It does not cross the placenta and is recommended by RCOG and ASH guidance. Timing around delivery and neuraxial anaesthesia requires obstetric, haematology and anaesthetic coordination; life-threatening unstable PE follows a different emergency pathway.

Therapeutic LMWH is preferred for acute VTE during pregnancy.
Pregnancy-associated PE: therapeutic LMWH, not a DOAC or warfarin.
Continue treatment through pregnancy and at least six weeks postpartum, with at least three months total therapy.

3. Immediate assessment

Recognise nausea, confusion, visual disturbance and seizures.
Confusion and low sodium after TURP → consider TURP syndrome.

Clinical recognition and differential diagnosis

Management depends on symptom severity and measured sodium.

Common examiner traps

Not every TURP patient has the same risk; irrigation system and fluids matter.

Rapid-recall exam pearls

Pregnancy-associated PE: therapeutic LMWH, not a DOAC or warfarin.
Confusion and low sodium after TURP → consider TURP syndrome.

Haematology

Blood, coagulation and haematological malignancy

Overview. Interpret anaemia, bleeding and malignant blood disease through cell counts, blood film, coagulation studies and characteristic systemic features.

Topic map — key distinctions

Subtopic	Defining feature / key principle
Anaemia and haemolysis	Aplastic anaemia is marrow failure causing pancytopenia: neutropenia leads to infection, thrombocytopenia to bruising and anaemia to fatigue.
Coagulation and bleeding	Aspirin irreversibly inhibits platelet COX-1, reducing thromboxane A2 synthesis and platelet aggregation.

1. Anaemia and haemolysis

Aplastic anaemia is marrow failure causing pancytopenia: neutropenia leads to infection, thrombocytopenia to bruising and anaemia to fatigue. Reticulocytes are low, and the marrow is hypocellular.

CRAB features: hyperCalcaemia, Renal failure, Anaemia, Bone lesions.
Hypercalcaemia, renal impairment, anaemia and lytic bone disease.
Classical presentation combines infection, bleeding and anaemia.
Aplastic anaemia is hypocellular bone marrow failure.
Typical diarrhoea-associated HUS follows Shiga-toxin-producing E. coli infection, classically serotype O157:H7. Endothelial injury causes microangiopathic haemolytic anaemia, thrombocytopenia and acute kidney injury.

2. Coagulation and bleeding

Aspirin irreversibly inhibits platelet COX-1, reducing thromboxane A2 synthesis and platelet aggregation. Anucleate platelets cannot synthesise replacement COX-1, so the antiplatelet effect persists for the life of affected platelets.

Early INR rise on warfarin reflects short-lived factor VII, not immediate full anticoagulation.
Platelet count can remain normal despite impaired function.
Platelets lack nuclei and cannot replace acetylated COX-1.
Platelet lifespan is approximately 7–10 days.

Clinical recognition and differential diagnosis

Multiple myeloma is a clonal plasma-cell malignancy producing monoclonal immunoglobulin or free light chains; bone lesions are typically lytic, and renal dysfunction or anaemia may occur.
B symptoms include unexplained fever, drenching night sweats and unintentional weight loss.
Typing amyloid requires additional immunohistochemical or mass-spectrometry methods.

Investigations and diagnostic interpretation

By validated tissue typing, ideally mass spectrometry when available, interpreted with the clinical work-up.
Excisional biopsy is often preferred when lymphoma is suspected because architecture is important.
Assess transferrin saturation and ferritin in suspected iron overload.
Marrow biopsy and exclusion of reversible causes are required.

Management and operative principles

Avoid antimotility agents in suspected STEC infection; antibiotic decisions require specialist guidance.

Common examiner traps

Not all renal failure in myeloma is amyloidosis; cast nephropathy is common and must be distinguished.
Do not confuse STEC-HUS with TTP; severe ADAMTS13 deficiency is characteristic of immune TTP.
Blue tissue stain is not a diagnosis by itself; interpret distribution and iron studies.
Early protein C reduction can transiently favour thrombosis before full anticoagulation.
Do not mistake osteoporotic vertebral collapse alone for diagnostic evidence of myeloma.

Rapid-recall exam pearls

Early INR rise on warfarin reflects short-lived factor VII, not immediate full anticoagulation.
Pancytopenia plus low reticulocytes and no splenomegaly strongly suggests marrow failure.
Rubbery painless nodes in several regions plus B symptoms: think lymphoma.
Bence Jones proteinuria plus punched-out skull lesions suggests myeloma.
Myeloma plus amyloid = AL; chronic inflammation plus amyloid = AA.

Haematology and coagulation

Overview. Distinguish platelet dysfunction from coagulation-factor abnormalities by bleeding pattern and screening tests.

Topic map — key distinctions

Subtopic	Defining feature / key principle
Platelet disorders	Platelet dense (delta) granules contain ADP, ATP, calcium and serotonin.
Coagulation factor defects	Platelet dense (delta) granules contain ADP, ATP, calcium and serotonin.

1. Platelet disorders

Platelet dense (delta) granules contain ADP, ATP, calcium and serotonin. Released ADP activates platelet P2Y receptors, reinforcing recruitment and aggregation. Fibrinogen, vWF and growth factors are largely alpha-granule proteins.

Dense-granule deficiency can cause a platelet-type mucocutaneous bleeding phenotype.
Platelet number can be normal despite a significant qualitative secretion defect.

2. Coagulation factor defects

Alpha granules contain vWF, fibrinogen, factor V and growth factors.
Dense = small molecules (ADP, calcium, serotonin); alpha = adhesive proteins and growth factors.

Applied anatomy and pathology

The P2Y12 receptor, inhibited by clopidogrel and related agents.

Clinical recognition and differential diagnosis

Megaloblastic anaemia can result from either folate or B12 deficiency.

Investigations and diagnostic interpretation

Assess underlying cause and response; do not rely solely on MCV to exclude deficiency.

Management and operative principles

Confirmed vitamin B12 deficiency with neurological involvement warrants prompt B12 replacement, usually intramuscular hydroxocobalamin, with urgent haematology or specialist input in pregnancy. Folic acid alone can improve anaemia without treating neurological injury and may delay recognition.
With neurological involvement in pregnancy, seek urgent advice and consider IM hydroxocobalamin.

Common examiner traps

Do not confuse dense granule calcium with alpha-granule fibrinogen or vWF.

Rapid-recall exam pearls

Dense = small molecules (ADP, calcium, serotonin); alpha = adhesive proteins and growth factors.
Macrocytosis + neuropathy + low B12 in pregnancy → urgent B12 replacement, not folate alone.

Lymphatic and lymphoproliferative disorders

Overview. Persistent unexplained lymphadenopathy requires tissue diagnosis and assessment of systemic features; lymphoma classification drives treatment.

Topic map — key distinctions

Subtopic	Defining feature / key principle
Lymphoma investigation	Painless lymph-node enlargement in multiple noncontiguous regions can suggest lymphoma, although infection and systemic inflammatory disease remain alternatives.
Systemic symptoms	Unexplained fever, drenching night sweats and significant unintentional weight loss.

1. Lymphoma investigation

Painless lymph-node enlargement in multiple noncontiguous regions can suggest lymphoma, although infection and systemic inflammatory disease remain alternatives. Evaluation includes history for B symptoms and appropriately selected imaging and biopsy.

Persistent generalised painless lymphadenopathy requires lymphoma assessment.
FNAC alone may be insufficient to classify lymphoma fully.

2. Systemic symptoms

Unexplained fever, drenching night sweats and significant unintentional weight loss.

Ask about fever, night sweats and weight loss.
Painless lymph-node enlargement in multiple noncontiguous regions can suggest lymphoma, although infection and systemic inflammatory disease remain alternatives. Evaluation includes history for B symptoms and appropriately selected imaging and biopsy.

Clinical recognition and differential diagnosis

Posterior cervical lymphadenopathy is a useful clinical clue.

Investigations and diagnostic interpretation

Excisional node biopsy may be required to preserve architecture.
Assess spleen and liver enlargement.

Common examiner traps

EBV serology, not a single heterophile test, is preferred for clarifying atypical cases.
FNAC alone may be insufficient to classify lymphoma fully.

Rapid-recall exam pearls

Pharyngitis + posterior cervical nodes + splenomegaly in a young adult = consider EBV.
Persistent generalised painless lymphadenopathy requires lymphoma assessment.

Nutritional and megaloblastic anaemias

Overview. Macrocytic anaemia may reflect B12 or folate deficiency, marrow disease or medication; neurological findings are especially relevant to B12 deficiency.

Topic map — key distinctions

Subtopic	Defining feature / key principle
Vitamin B12	Always check vitamin B12 before treating presumed folate deficiency because folate can mask B12-associated anaemia while neurological injury progresses.
Folate	Macrocytosis with megaloblastic morphology, confirmed low folate and normal B12 identifies folate-deficiency anaemia.
Blood film and workup	Macrocytosis with megaloblastic morphology, confirmed low folate and normal B12 identifies folate-deficiency anaemia.

1. Vitamin B12

Always check vitamin B12 before treating presumed folate deficiency because folate can mask B12-associated anaemia while neurological injury progresses.

The anaemia may improve while neurological complications of B12 deficiency remain untreated.

2. Folate

Macrocytosis with megaloblastic morphology, confirmed low folate and normal B12 identifies folate-deficiency anaemia. Treat with therapeutic folic acid (commonly 5 mg daily in UK practice, adjusted to the clinical situation) and address dietary or absorption causes; this differs from routine 400-microgram prophylaxis for neural-tube-defect prevention.

Low folate with normal B12 in pregnancy: therapeutic folic acid, after checking B12.
Always check vitamin B12 before treating presumed folate deficiency because folate can mask B12-associated anaemia while neurological injury progresses.
Treatment-dose folate is different from prophylactic folate used before conception and early pregnancy.
Folate demand rises during pregnancy.
Macrocytosis alone does not distinguish folate deficiency from B12 deficiency.

3. Blood film and workup

Macrocytosis alone does not distinguish folate deficiency from B12 deficiency.

Common examiner traps

Macrocytosis alone does not distinguish folate deficiency from B12 deficiency.

Rapid-recall exam pearls

Low folate with normal B12 in pregnancy: therapeutic folic acid, after checking B12.

Neurosurgery

Brain and spinal tumours

Overview. A space-occupying intracranial tumour can produce vasogenic oedema and mass effect; treatment of swelling must not obscure tissue diagnosis.

Topic map — key distinctions

Subtopic	Defining feature / key principle
Vasogenic oedema and steroid therapy	Dexamethasone reduces blood–brain barrier permeability and vasogenic oedema surrounding many intracranial tumours, alleviating mass effect and raised-pressure symptoms.
Lumbar puncture and herniation risk	A space-occupying intracranial lesion with mass effect and midline shift creates a dangerous intracranial pressure gradient.
Diagnosis and emergency referral	Suspected CNS lymphoma warrants special caution before biopsy.

1. Vasogenic oedema and steroid therapy

Dexamethasone reduces blood–brain barrier permeability and vasogenic oedema surrounding many intracranial tumours, alleviating mass effect and raised-pressure symptoms. It is not routinely appropriate for every intracranial lesion and can affect histological diagnosis of suspected primary CNS lymphoma.

Dexamethasone treats vasogenic oedema around brain tumours.

2. Lumbar puncture and herniation risk

A space-occupying intracranial lesion with mass effect and midline shift creates a dangerous intracranial pressure gradient. Removing CSF by lumbar puncture can precipitate transtentorial or tonsillar herniation. Specialist neurosurgical management and treatment of the underlying lesion take priority.

Mass lesion with midline shift → avoid lumbar puncture because of herniation risk.

3. Diagnosis and emergency referral

Suspected CNS lymphoma warrants special caution before biopsy.
Steroid response should not be mistaken for cure; steroids can obscure a CNS lymphoma biopsy.
Dexamethasone reduces blood–brain barrier permeability and vasogenic oedema surrounding many intracranial tumours, alleviating mass effect and raised-pressure symptoms. It is not routinely appropriate for every intracranial lesion and can affect histological diagnosis of suspected primary CNS lymphoma.

Clinical recognition and differential diagnosis

Do not confuse isolated papilloedema in other conditions with a demonstrated mass causing midline shift.
A demonstrated space-occupying lesion with mass effect is a major contraindication to LP.
Barrier leak versus cellular energy-failure swelling.

Investigations and diagnostic interpretation

Papilloedema plus a suspected mass warrants urgent assessment for intracranial pathology.

Management and operative principles

Neurological deterioration, seizures and pupillary abnormalities require urgent escalation.

Common examiner traps

Steroid response should not be mistaken for cure; steroids can obscure a CNS lymphoma biopsy.

Rapid-recall exam pearls

Mass lesion with midline shift → avoid lumbar puncture because of herniation risk.
Dexamethasone treats vasogenic oedema around brain tumours.

Neurological anatomy and clinical syndromes

Overview. Localise central and peripheral lesions using named tracts, visual pathways, cranial nerves and characteristic sensorimotor deficits.

Topic map — key distinctions

Subtopic	Defining feature / key principle
Motor and sensory tracts	Anterior spinal artery infarction damages corticospinal and spinothalamic pathways and autonomic tracts, producing weakness, pain/temperature loss and bladder dysfunction.
Neurovascular localisation	Sudden focal weakness requires an emergency stroke pathway and vascular imaging.

1. Motor and sensory tracts

Anterior spinal artery infarction damages corticospinal and spinothalamic pathways and autonomic tracts, producing weakness, pain/temperature loss and bladder dysfunction. Posterior columns are relatively spared because they are supplied predominantly by the posterior spinal arteries.

Corticospinal injury causes motor weakness; spinothalamic injury impairs pain and temperature.

2. Neurovascular localisation

Sudden focal weakness requires an emergency stroke pathway and vascular imaging.

Acute cerebellar symptoms require urgent stroke assessment.

Applied anatomy and pathology

A lesion posterior to the optic chiasm produces a contralateral homonymous field defect. The optic radiations traverse the temporal and parietal lobes; right parietal radiation involvement particularly affects the left inferior visual quadrant, although larger lesions may produce a broader homonymous hemianopia.
Superior optic radiation fibres traverse the parietal lobe and carry information from the contralateral inferior visual field. A left parietal lesion therefore produces a right inferior homonymous quadrantanopia (“pie on the floor”). Temporal Meyer-loop lesions instead produce contralateral superior quadrantanopia.
PICA territory infarction can involve the lateral medulla and inferior cerebellum, causing a lateral medullary (Wallenberg) pattern: vestibular symptoms, dysphagia, ipsilateral facial and contralateral body sensory deficits, and ataxia.

Clinical recognition and differential diagnosis

A central syrinx expands near the central canal and disrupts crossing second-order spinothalamic fibres at the anterior white commissure. This causes segmental, bilateral suspended pain/temperature loss with relative preservation of dorsal-column vibration and proprioception early in disease.
The anterior cerebral artery supplies much of the medial frontal and parietal cortex, including the leg region of the primary motor and sensory homunculus. A left ACA infarct causes contralateral (right) leg-predominant weakness; abulia and urinary incontinence may also occur.
Lambert–Eaton syndrome is classically associated with small-cell lung cancer, not thymoma.

Investigations and diagnostic interpretation

The highly vascular, fragile subependymal germinal matrix in premature infants is especially vulnerable to haemorrhage. Bleeding begins near the caudothalamic groove and may extend into the ventricles; cranial ultrasonography is the standard bedside screening technique.
The internal vertebral venous plexus is a valveless network in the epidural space. A traumatic needle pass can injure epidural vessels, producing blood that often clears in successive CSF tubes; this is not by itself proof that intracranial haemorrhage is absent.
Dysdiadochokinesia, intention tremor, limb ataxia and gaze-evoked nystagmus are classic cerebellar signs. The specific vascular territory requires additional examination and imaging.
A traumatic tap and subarachnoid haemorrhage can overlap; interpret with clinical context and appropriate testing.

Measurements, staging and thresholds

Grade I is confined to the germinal matrix; more extensive haemorrhage enters the ventricles.

Common examiner traps

Differentiate MG from Lambert–Eaton: MG often has ocular symptoms; Lambert–Eaton often has autonomic features and facilitation.
Clearing of blood across tubes is suggestive, not a perfect exclusion test for subarachnoid haemorrhage.
A pure cerebellar syndrome without medullary signs is not sufficient to localise confidently to PICA.
Posterior communicating artery is an ICA branch, but posterior cerebral artery is usually not.
Do not assign a specific cerebellar artery without a compatible vascular syndrome.

Rapid-recall exam pearls

Preterm infant plus caudothalamic-groove echogenicity strongly suggests germinal-matrix haemorrhage.
Traumatic lumbar puncture may injure epidural veins in the internal vertebral venous plexus.
Dysphagia plus crossed sensory loss and ataxia suggests PICA/lateral medullary infarction.
Internal carotid artery gives off the ophthalmic artery; cervical segment is branchless.
Syringomyelia = anterior white commissure damage with suspended pain-temperature loss.

Raised ICP and cerebrovascular

Overview. A fall in intracranial compliance magnifies volume-related pressure changes; distinguish diffuse raised pressure from focal vascular deficits.

Topic map — key distinctions

Subtopic	Defining feature / key principle
Raised intracranial pressure	Assess contraindications, including raised ICP with mass effect and coagulopathy.

1. Raised intracranial pressure

Assess contraindications, including raised ICP with mass effect and coagulopathy.

Applied anatomy and pathology

The cerebral aqueduct is a narrow midbrain channel connecting the third and fourth ventricles. Aqueductal stenosis is an established cause of obstructive hydrocephalus with dilatation of the lateral and third ventricles.
The aqueduct connects the third and fourth ventricles and is a narrow CSF passage. Aqueductal stenosis produces dilatation of the lateral and third ventricles with a relatively normal fourth ventricle.
The cerebral aqueduct connects the third to the fourth ventricle. Obstruction dilates the ventricles upstream (lateral and third) while leaving the fourth ventricle relatively normal.

Clinical recognition and differential diagnosis

Asymptomatic metastases without mass effect do not routinely require corticosteroids.
Central diabetes insipidus is associated with hypotonic polyuria and hypernatraemia.

Investigations and diagnostic interpretation

CT evaluates bony injury while MRI can assess cord and ligament pathology.
Mass effect and blood–brain barrier disruption producing vasogenic oedema.
Assess for raised intracranial pressure and neurodevelopmental effects.
MRI ventricular pattern helps localise the obstruction.

Management and operative principles

Coordinate surgery, stereotactic radiotherapy or other oncological treatment.

Measurements, staging and thresholds

Central cord syndrome, often after hyperextension in a stenotic cervical canal, preferentially impairs upper-limb motor function more than lower-limb function. The somatotopic and tract injury pattern is variable in clinical practice.

Common examiner traps

Do not confuse cerebral salt wasting (typically hyponatraemia) with central DI (often hypernatraemia).
Landmarks are imperfect in obesity or altered anatomy; ultrasound may improve level selection.
Do not use prophylactic anticonvulsants automatically in seizure-free brain metastases.
Do not confuse communicating hydrocephalus with focal obstruction of the aqueduct.
Do not confuse the cerebral aqueduct with a fourth-ventricular exit foramen.

Rapid-recall exam pearls

SAH plus hypernatraemia, very dilute high-volume urine and desmopressin response points to central DI.
Dexamethasone treats symptomatic vasogenic oedema; it does not treat the metastasis itself.
Upper limbs weaker than lower limbs after cervical injury = central cord syndrome.
Aqueductal stenosis enlarges lateral and third ventricles but spares the fourth.
Large lateral + third ventricles with spared fourth = aqueduct obstruction.

Traumatic brain injury

Overview. Head injury assessment combines Glasgow Coma Scale, pupils, focal signs and anticoagulant status to identify patients needing imaging or urgent surgery.

Topic map — key distinctions

Subtopic	Defining feature / key principle
GCS and initial assessment	GCS 15/baseline, no ongoing clinical concerns, safe supervision, clear return precautions and written advice.
Extra-axial haemorrhage	Chronic subdural haematoma may follow seemingly trivial trauma.
Brain herniation	Coma plus an ipsilateral blown pupil and contralateral weakness = suspect uncal herniation.

1. GCS and initial assessment

GCS 15/baseline, no ongoing clinical concerns, safe supervision, clear return precautions and written advice.

EDH volume greater than 30 cm³ is an operative indication regardless of GCS.
Typically volume under 30 cm³, thickness under 15 mm, shift under 5 mm, GCS above 8 and no focal deficit, with neurosurgical observation and serial CT.
Falling GCS plus unilateral fixed dilated pupil = suspect herniation until proved otherwise.

2. Extra-axial haemorrhage

Chronic subdural haematoma may follow seemingly trivial trauma.

3. Brain herniation

Coma plus an ipsilateral blown pupil and contralateral weakness = suspect uncal herniation.

Applied anatomy and pathology

Progressive morning headache and vomiting are red flags for a space-occupying lesion.
Parasympathetic fibres carried with the oculomotor nerve (CN III).
The pupil is usually ipsilateral to the expanding lesion.

Clinical recognition and differential diagnosis

A supratentorial mass lesion can displace the medial temporal uncus through the tentorial opening. Compression of the ipsilateral oculomotor nerve produces a dilated, poorly reactive pupil, while compression of descending motor fibres usually causes contralateral weakness. This is an immediate neurosurgical emergency.
Expanding supratentorial mass effect can displace the medial temporal lobe through the tentorial notch, compressing the ipsilateral oculomotor nerve and causing a dilated unreactive pupil. This is a neurosurgical emergency associated with brainstem compromise.
A gradually expanding intracranial tumour can elevate intracranial pressure and cause progressive morning headaches, vomiting and papilloedema. Lack of focal neurological signs does not exclude a frontal mass.

Investigations and diagnostic interpretation

The Cushing response occurs when severe intracranial hypertension threatens cerebral perfusion and brainstem function. Sympathetic activation raises systemic blood pressure; reflex vagal slowing produces bradycardia, while brainstem dysfunction causes abnormal respiration. It is a late, ominous sign.
Chronic subdural blood collects between dura and arachnoid, commonly following tearing of bridging veins in older patients after minor trauma. The crescentic collection may cross sutures and becomes hypodense as blood products age.
CTA/MRA may suggest the diagnosis; digital subtraction angiography defines anatomy for treatment.
EDH classically appears lentiform/biconvex on CT and is limited by cranial sutures.

Management and operative principles

Urgent neuroimaging and neurosurgical management are required when clinically appropriate.
Symptomatic collections with mass effect warrant urgent neurosurgical assessment.
Threatened vision or high-flow fistula requires urgent specialist management.
Prevent hypoxaemia and hypotension while arranging urgent definitive care.

Measurements, staging and thresholds

Cerebral perfusion pressure (CPP) is the driving pressure for cerebral blood flow and is calculated as CPP = MAP − ICP. Therefore 78 − 18 = 60 mmHg. The Brain Trauma Foundation suggests targeting approximately 60–70 mmHg in severe traumatic brain injury, depending on physiology.
The BTF recommends treating sustained ICP above 22 mmHg, interpreted with the clinical and imaging context.
Aggressively driving CPP above 70 mmHg with fluids and vasopressors can increase complications.
Small EDH may be observed only under strict neurosurgical criteria and repeat imaging.

Common examiner traps

A burr hole may be a temporising decompression in exceptional circumstances, but is not the default definitive treatment for a large organised EDH.
Intoxication and living alone are independent safety considerations; a normal scan does not make them disappear.
Cavernous sinus thrombosis and fistula both cause ocular congestion, but a bruit favours a fistula.
Alcohol history alone cannot diagnose a haemorrhage; the original recall lacked diagnostic imaging.
Never perform routine lumbar puncture before excluding a mass lesion when raised ICP is suspected.

Rapid-recall exam pearls

Falling GCS plus unilateral fixed dilated pupil = suspect herniation until proved otherwise.
Older patient + delayed confusion + crescentic extra-axial CT collection = chronic subdural.
Coma plus an ipsilateral blown pupil and contralateral weakness = suspect uncal herniation.
Hypertension + bradycardia + irregular respiration after head trauma = Cushing triad.
Deteriorating patient + large biconvex EDH: emergency neurosurgical evacuation.

Obstetrics & Gynaecology

Gynaecological emergencies and pelvic anatomy

Overview. Acute pelvic symptoms require attention to pregnancy status, bleeding and life-threatening adnexal or uterine pathology.

Topic map — key distinctions

Subtopic	Defining feature / key principle
Ectopic and bleeding	A ruptured tubal ectopic pregnancy can cause rapid intraperitoneal haemorrhage, circulatory collapse and diaphragmatic irritation producing shoulder-tip pain.

1. Ectopic and bleeding

A ruptured tubal ectopic pregnancy can cause rapid intraperitoneal haemorrhage, circulatory collapse and diaphragmatic irritation producing shoulder-tip pain. Pregnancy testing, resuscitation and immediate gynaecological/surgical assessment are essential.

Reproductive-age patient + shock + abdominal and shoulder-tip pain = ruptured ectopic pregnancy until excluded.

Applied anatomy and pathology

Diaphragmatic irritation referred through the phrenic nerve (C3–C5).

Investigations and diagnostic interpretation

Bedside ultrasound may reveal free intraperitoneal fluid but should not delay life-saving surgery in an unstable patient.

Management and operative principles

A negative pregnancy history does not exclude pregnancy; obtain urgent hCG testing.
RhD status and anti-D prophylaxis considerations follow local obstetric guidance.

Common examiner traps

Do not await a formal scan in a profoundly unstable patient if surgical management is urgently required.

Rapid-recall exam pearls

Reproductive-age patient + shock + abdominal and shoulder-tip pain = ruptured ectopic pregnancy until excluded.

Gynaecological oncology and pelvic anatomy

Overview. Gynaecological cancer staging follows local invasion and regional nodal drainage; pelvic anatomy governs operative complication risk.

Topic map — key distinctions

Subtopic	Defining feature / key principle
Cervical cancer and lymphatics	The cervix drains chiefly to parametrial, obturator, internal iliac and external iliac lymphatic chains, with subsequent common iliac and para-aortic spread.
Ovarian tumours	Ovarian lymphatics accompany the ovarian vessels in the suspensory ligament toward the para-aortic and paracaval retroperitoneal nodes, reflecting the ovary’s embryological origin high in the posterior abdomen.
Vulval and vaginal drainage	Most of the vulva, including the labia majora, drains initially to superficial inguinal nodes, then to deep inguinofemoral and pelvic groups.
Pelvic surgery anatomy	The ureter passes under the uterine artery: water under the bridge.

1. Cervical cancer and lymphatics

The cervix drains chiefly to parametrial, obturator, internal iliac and external iliac lymphatic chains, with subsequent common iliac and para-aortic spread. Internal iliac nodes are therefore a principal regional drainage basin.

The bladder base lies anterior to the upper vagina and cervix. Dissection in this plane during hysterectomy or anterior vaginal surgery risks bladder injury and vesicovaginal fistula. The ureters also pass close to the lateral cervix and uterine artery and must be identified separately.
The uterine cervix is not primarily an inguinal-draining organ.
The ureter passes beneath the uterine artery near the cervix.
Cervix drains to pelvic iliac/obturator nodes, not superficial inguinal nodes.
Vulva → superficial inguinal nodes; cervix → pelvic iliac/obturator nodes.

2. Ovarian tumours

Ovarian lymphatics accompany the ovarian vessels in the suspensory ligament toward the para-aortic and paracaval retroperitoneal nodes, reflecting the ovary’s embryological origin high in the posterior abdomen.

The ovary develops in the posterior abdomen and descends, retaining its vascular and lymphatic route.
Ovary → para-aortic nodes; scrotal skin → superficial inguinal nodes.
Do not confuse the ovary with the vulva or cervix when choosing regional nodes.

3. Vulval and vaginal drainage

Most of the vulva, including the labia majora, drains initially to superficial inguinal nodes, then to deep inguinofemoral and pelvic groups. Lateral vulvar tumours often spread ipsilaterally, whereas near-midline lesions can drain bilaterally. The original recall mentioned postcoital bleeding and inguinal nodes but did not identify a vulvar primary.

Vulvar and distal vaginal lymphatics commonly reach superficial inguinal nodes first.
Lower vaginal and vulval tumours may drain to inguinal nodes; do not transfer that pattern to cervical cancer.
Vaginal lymphatic drainage depends on tumour level. The distal third drains predominantly to inguinal and femoral nodes, whereas the upper vagina drains to pelvic chains including obturator and iliac nodes. Mid-vaginal lesions can drain to both territories.
Exclude cervical and vulval extension before classifying a primary vaginal carcinoma.
Lower third vagina → inguinal-femoral nodes.

4. Pelvic surgery anatomy

The ureter passes under the uterine artery: water under the bridge.
The ureter passes beneath the uterine artery near the cervix.
The bladder base lies anterior to the upper vagina and cervix. Dissection in this plane during hysterectomy or anterior vaginal surgery risks bladder injury and vesicovaginal fistula. The ureters also pass close to the lateral cervix and uterine artery and must be identified separately.

Applied anatomy and pathology

Through parametrial tissues into adjacent pelvic structures; lymphatic dissemination occurs through regional pelvic chains.
Cervical carcinoma usually drains first to pelvic iliac and obturator groups rather than superficial inguinal nodes.
Posterior labial branches of the pudendal nerve supply the posterior labia.

Management and operative principles

The ilioinguinal nerve supplies the anterior labia majora and adjacent upper medial thigh. Its terminal sensory branches traverse the superficial inguinal ring and can be injured during open groin surgery. The posterior labia majora have additional pudendal/perineal sensory innervation.
Cervical lymphatics drain via parametrial pathways to obturator, internal iliac, external iliac and sacral pelvic nodes, with subsequent common iliac and para-aortic spread. Internal iliac nodes are a principal regional group.
Vulvar lymphatics communicate across the midline, allowing contralateral inguinofemoral drainage.
Pelvic surgical planes should be developed with awareness of the bladder reflection.

Measurements, staging and thresholds

FIGO 2018 introduced stage IIIC for nodal involvement irrespective of primary tumour size or local extension. IIIC1 denotes pelvic lymph-node metastases; IIIC2 denotes para-aortic lymph-node metastases. The suffix r indicates radiologically established nodal involvement, whereas p denotes pathological confirmation.
Pelvic MRI assesses local tumour extent; nodal staging uses appropriate cross-sectional imaging.
Staging and treatment use cross-sectional imaging and specialist oncology assessment.
The suffix r denotes imaging-based nodal staging.

Common examiner traps

Postcoital bleeding alone suggests several gynaecological diagnoses; a definite labial lesion is needed before attributing inguinal nodes to vulvar cancer.
Lower vaginal and vulval tumours may drain to inguinal nodes; do not transfer that pattern to cervical cancer.
Bilateral inguinal nodes alone do not identify a primary lesion; the source lacked an examination or biopsy.
The whole labia majora do not have a single exclusive nerve supply; specify anterior versus posterior.
Do not confuse cervical cancer drainage with lower vaginal or vulval drainage to groin nodes.

Rapid-recall exam pearls

Distal vagina follows vulval groin-node drainage; upper vagina follows pelvic-node drainage.
Internal iliac and obturator nodes are high-yield regional stations in cervical carcinoma.
Cervical cancer pelvic-node metastases are FIGO IIIC1; para-aortic nodes are IIIC2.
Anterior labia majora = ilioinguinal nerve; posterior labia = pudendal branches.
Cervix drains to pelvic iliac/obturator nodes, not superficial inguinal nodes.

Oncology

Cancer immunotherapy and palliation

Overview. Cancer palliation controls symptoms while respecting prognosis, functional status and patient goals; treatments may be disease-modifying or purely supportive.

Topic map — key distinctions

Subtopic	Defining feature / key principle
Immune therapy	PD-1 inhibitors block an inhibitory checkpoint on activated T cells, restoring antitumour immune responses in responsive cancers.

1. Immune therapy

PD-1 inhibitors block an inhibitory checkpoint on activated T cells, restoring antitumour immune responses in responsive cancers. Clinical benefit depends on tumour biology and regimen selection.

Another T-cell inhibitory checkpoint targeted by ipilimumab.

Common examiner traps

Immunotherapy toxicities may resemble autoimmune disease rather than classic cytotoxic side effects.

Rapid-recall exam pearls

PD-1 blockade = immunotherapy, not conventional chemotherapy.

Cancer metastasis and staging

Overview. Cancer staging describes tumour extent and guides treatment selection; different histologies have characteristic nodal and distant spread.

Topic map — key distinctions

Subtopic	Defining feature / key principle
Assessing extent	Treatment generally combines systemic chemotherapy and oncological resection.

1. Assessing extent

Treatment generally combines systemic chemotherapy and oncological resection.
Malignant osteoid formed directly by tumour cells.
Osteosarcoma commonly disseminates haematogenously, with the lung as its principal metastatic destination. Chest CT is important for staging and surveillance.

Investigations and diagnostic interpretation

Biopsy should be planned by a specialist sarcoma team.

Common examiner traps

A poorly placed diagnostic biopsy can compromise definitive limb-sparing surgery.

Rapid-recall exam pearls

Osteosarcoma metastasises most commonly to lung.

Orthopaedics

Fracture assessment and fixation

Overview. Fracture management starts with soft-tissue and neurovascular assessment, followed by stability assessment, reduction and appropriate fixation.

Topic map — key distinctions

Subtopic	Defining feature / key principle
Initial assessment	Acute compartment syndrome threatens muscle and nerve viability because tissue pressure impairs microvascular perfusion.
Reduction and immobilisation	After reduction, assess for osteochondral fracture and medial patellofemoral ligament injury.
Fixation principles	Slipped capital femoral epiphysis is posteroinferior displacement of the femoral epiphysis relative to the metaphysis through the growth plate.

1. Initial assessment

Acute compartment syndrome threatens muscle and nerve viability because tissue pressure impairs microvascular perfusion. Immediate removal of external constriction, keeping the limb near heart level, resuscitation and urgent complete fasciotomy of the involved compartments are indicated when the diagnosis is established. Do not wait for absent pulses.

2. Reduction and immobilisation

After reduction, assess for osteochondral fracture and medial patellofemoral ligament injury.

An apparently increased anterior drawer may reflect reduction of a posteriorly sagged tibia, not ACL rupture.

3. Fixation principles

Slipped capital femoral epiphysis is posteroinferior displacement of the femoral epiphysis relative to the metaphysis through the growth plate. Clinical clues include an obese adolescent, limp, referred knee pain and Drehmann sign.

SUFE is displacement through the proximal femoral growth plate, classically in overweight adolescents. Obligatory external rotation on flexion (Drehmann sign) is a strong clinical clue. The patient should stop weight bearing and receive urgent orthopaedic assessment.
In children, sluggish blood flow in metaphyseal capillary loops adjacent to the growth plate favours haematogenous bacterial seeding, particularly in rapidly growing long bones.
Meniscotibial capsular attachments securing the peripheral meniscal rim to the tibial plateau.

Applied anatomy and pathology

The ACL resists anterior tibial translation and contributes to rotational stability. Acute rupture commonly causes rapid haemarthrosis due to intra-articular bleeding and produces an increased anterior translation with a soft endpoint on Lachman testing.
The sciatic nerve supplies the hamstrings and divides into tibial and common fibular components that control most ankle and foot movements. The medial leg is largely supplied by the saphenous branch of the femoral nerve.
The popliteal artery runs close to the posterior capsule and proximal tibia. Overpenetration of the saw or instruments can cause potentially limb-threatening arterial injury.

Clinical recognition and differential diagnosis

Quadriceps tendon rupture separates the quadriceps mechanism from the superior patellar pole. It typically occurs in older patients after a stumble or eccentric load and produces a suprapatellar gap, loss of active extension and sometimes patella baja due to unopposed patellar-tendon traction.
Distal pulses may remain palpable until late because compartment pressure can impair capillary perfusion well before exceeding arterial systolic pressure. Severe pain, pain on passive stretch and evolving sensory change are more useful early clues.
A laterally displaced patella produces visible or palpable lateral prominence, severe pain and an unwillingness to extend or flex the knee. Recurrent giving-way may reflect underlying patellofemoral instability.

Investigations and diagnostic interpretation

Passive great-toe extension stretches flexor hallucis longus, which occupies the deep posterior leg compartment. Disproportionate pain on passive stretch is an early warning sign of compartment syndrome, but no single examination sign reliably confirms or excludes it.
Intra-articular contrast distends the joint and outlines labral defects on direct MR arthrography. Modern high-resolution 3-T MRI may also be diagnostically excellent, and imaging choice depends on local expertise and clinical context.
Patellar tendon length divided by greatest diagonal patellar length on a true lateral knee radiograph; normal is approximately 0.8–1.2.
Assess tense compartments, pain progression, sensory changes and analgesic requirements; serial examination is essential.

Management and operative principles

Urgent fasciotomy is required when acute compartment syndrome is clinically diagnosed; pressure assessment assists uncertain cases.
Neurological compromise, instability, deformity, refractory infection or need for drainage.
New weakness, sphincter dysfunction or epidural abscess requires urgent spinal assessment.
A postoperative expanding haematoma or pulse deficit requires urgent vascular assessment.

Measurements, staging and thresholds

The ACL restrains anterior translation of the tibia relative to the femur. Rupture commonly produces acute haemarthrosis within hours and abnormal anterior drawer or Lachman testing. Lachman testing at 20–30 degrees of flexion is generally more sensitive for acute ACL injury.
Multiple myeloma is a clonal plasma-cell disorder associated with CRAB features (hyperCalcaemia, Renal dysfunction, Anaemia and Bone lesions). Serum electrophoresis, immunofixation and free light chains assess monoclonal protein; diagnosis requires marrow evaluation and accepted myeloma-defining criteria.
Diastolic blood pressure minus compartment pressure; a small difference (often ≤30 mmHg) supports impaired perfusion in context.
Delta pressure (diastolic BP minus compartment pressure) ≤30 mmHg supports concern in the correct context.

Common examiner traps

A patient may retain partial straight-leg raising if retinacular fibres remain intact; a preserved movement does not always exclude a partial or retinaculum-supported tear.
An ACL tear may coexist with knee swelling, but preserved active extension distinguishes it from complete extensor-mechanism disruption.
Dense bone in chronic osteomyelitis does not automatically establish Paget disease or fibrous dysplasia; identify the imaging anatomy.
A pathological fracture or periosteal reaction alone does not distinguish osteosarcoma from other aggressive lesions.
Differentiate tibial tubercle traction apophysitis from inferior patellar-pole Sinding–Larsen–Johansson syndrome.

Rapid-recall exam pearls

MR arthrography delineates intra-articular labral pathology; contemporary 3-T MRI is an alternative.
Medial meniscus is firmly tethered to deep MCL and capsule; lateral meniscus is not tethered to LCL.
Fixed flexion plus a displaced lateral patellar prominence points to lateral patellar dislocation.
Loss of knee flexion plus nearly all foot movements with spared medial leg = sciatic injury.
Infrapatellar gap + failed straight-leg raise + patella alta = patellar tendon rupture.

Hand, tendon and soft-tissue injuries

Overview. Hand injury assessment examines tendon function, digital perfusion and sensibility before anaesthesia; injury level determines repair strategy.

Topic map — key distinctions

Subtopic	Defining feature / key principle
Initial hand examination (anatomy-reference supplement)	Assess digital circulation, cutaneous sensibility and individual tendon function before wound anaesthesia; a normal resting posture does not exclude a partial tendon injury.
Surgical soft-tissue warnings recorded in this recall subsection	The two original records assigned here include acute compartment syndrome and distal biceps femoris anatomy; these should be retagged in a future source audit rather than falsely presented as hand-tendon recall…

1. Initial hand examination (anatomy-reference supplement)

Assess digital circulation, cutaneous sensibility and individual tendon function before wound anaesthesia; a normal resting posture does not exclude a partial tendon injury.

FDP is tested by stabilising the PIP joint and asking the patient to flex the DIP joint.
FDS flexion is assessed at the PIP joint while limiting FDP substitution by controlling adjacent fingers.
EPL injury reduces thumb IP extension and retropulsion with the palm resting on a table.

2. Surgical soft-tissue warnings recorded in this recall subsection

The two original records assigned here include acute compartment syndrome and distal biceps femoris anatomy; these should be retagged in a future source audit rather than falsely presented as hand-tendon recall questions.

Palpable distal pulses do not exclude compartment syndrome.
Suspected compartment syndrome requires immediate assessment and timely fasciotomy when clinically indicated.

Applied anatomy and pathology

Biceps femoris is the lateral hamstring. Its long head arises from the ischial tuberosity, and its tendon inserts predominantly on the head of the fibula. Sprinting loads the hamstrings eccentrically, particularly during terminal swing.
Distal lateral knee tenderness localises to biceps femoris tendon; medial tenderness suggests semitendinosus or semimembranosus.
Biceps femoris long head: tibial component of sciatic nerve; short head: common fibular component.

Investigations and diagnostic interpretation

Unreliable examination due to sedation or altered consciousness.

Measurements, staging and thresholds

Delta pressure (diastolic BP minus compartment pressure) ≤30 mmHg supports concern.

Common examiner traps

Do not wait for pulselessness, paralysis or pallor: these are late features.
Do not mistake lateral distal hamstring pain for gracilis injury.

Rapid-recall exam pearls

The lateral hamstring is biceps femoris; the two medial hamstrings are semitendinosus and semimembranosus.
Normal pulses do not exclude compartment syndrome.

Joints, ligaments and sports injuries

Overview. Joint pain must be localised through mechanism, range of motion, ligament tests and imaging rather than a single positive manoeuvre.

Topic map — key distinctions

Subtopic	Defining feature / key principle
Knee injuries and ACL	Effusion that develops over many hours can favour meniscal injury; rapid haemarthrosis raises concern for ACL or osteochondral injury.
Hip pathology	Slipped capital femoral epiphysis (SCFE/SUFE) often presents as referred knee pain in an adolescent, with restricted hip internal rotation and obligatory external rotation.
Shoulder pathology	The supraspinatus initiates shoulder abduction and contributes to cuff stability.
Acute compartment and haemarthrosis	Effusion that develops over many hours can favour meniscal injury; rapid haemarthrosis raises concern for ACL or osteochondral injury.

1. Knee injuries and ACL

Effusion that develops over many hours can favour meniscal injury; rapid haemarthrosis raises concern for ACL or osteochondral injury.

A torn ACL causes giving way; a displaced meniscus commonly causes true locking.
Document joint line tenderness and concomitant ACL and meniscal findings.
Do not use timing of effusion alone to exclude an ACL rupture or associated injuries.
Do not mistake a valgus stress test for an ACL test.
A twisting mechanism with joint-line pain, mechanical catching and delayed effusion is characteristic of a meniscal tear. An ACL rupture more often produces a rapid haemarthrosis within hours, often with a pop and instability; no single sign is perfectly diagnostic, so examination and imaging should be integrated.

2. Hip pathology

Slipped capital femoral epiphysis (SCFE/SUFE) often presents as referred knee pain in an adolescent, with restricted hip internal rotation and obligatory external rotation. Hip imaging is therefore essential despite normal knee radiographs. Obtain AP pelvis and an appropriate lateral view; use a cross-table lateral rather than frog-leg positioning when an unstable slip is suspected.

AP pelvis and lateral hip radiographs are first-line; avoid forced positioning in suspected unstable SCFE.
Untreated developmental dysplasia or dislocation can present after walking age with a limp, limited hip abduction, apparent limb-length discrepancy and a positive Galeazzi sign. Pelvic radiography is appropriate after ossification of the femoral head.
Transient synovitis is a self-limiting sterile inflammation of the hip often following a viral illness in young children. It produces a limp with relatively preserved general condition. Septic arthritis must still be actively excluded if fever, inability to bear weight or elevated inflammatory markers are present.
An acutely unwell febrile child with painful restricted hip movement and inability to weight-bear has septic arthritis until proved otherwise. Prompt orthopaedic assessment, blood cultures, imaging and joint aspiration are needed; drainage and antibiotics may be required.
Acute fever, non-weight-bearing and severe restriction of passive hip motion strongly suggest septic arthritis. This is a limb-threatening infection requiring urgent orthopaedic assessment, blood cultures, imaging/aspiration as appropriate and timely antibiotics and drainage.
Breech positioning is a major risk factor for developmental dysplasia of the hip (DDH). Reduced abduction and asymmetry in an infant warrant careful hip examination and age-appropriate ultrasonography, rather than reassurance from skin creases alone.

3. Shoulder pathology

The supraspinatus initiates shoulder abduction and contributes to cuff stability. Acute loss of active abduction with preserved passive motion after a painful event suggests a major rotator cuff tear.

Acute atraumatic shoulder pain plus amorphous supraspinatus calcification suggests hydroxyapatite deposition.
Do not equate all shoulder calcifications with CPPD or a rotator-cuff tear.

4. Acute compartment and haemarthrosis

Effusion that develops over many hours can favour meniscal injury; rapid haemarthrosis raises concern for ACL or osteochondral injury.

A twisting mechanism with joint-line pain, mechanical catching and delayed effusion is characteristic of a meniscal tear. An ACL rupture more often produces a rapid haemarthrosis within hours, often with a pop and instability; no single sign is perfectly diagnostic, so examination and imaging should be integrated.

Applied anatomy and pathology

S1 radiculopathy typically causes posterior calf/lateral-foot sensory symptoms, impaired plantar flexion and a reduced ankle jerk. L5 more commonly affects great-toe extension and dorsiflexion, whereas L4 affects knee extension and the patellar reflex.
Gluteus maximus is the major powerful extensor of the hip, particularly during rising, climbing and running. Hamstrings also extend the hip, but gluteus maximus is the principal muscle for forceful extension from flexion.
The superficial medial collateral ligament is the principal restraint to valgus loading at approximately 30° flexion. At full extension, substantial medial opening suggests additional capsular or cruciate disruption.

Clinical recognition and differential diagnosis

A meniscal tear may permit synovial fluid to extrude through the meniscal substance and form a cyst beside the joint line. Lateral parameniscal cysts often present as a focal swelling and are associated with horizontal cleavage tears.
A mid-range painful arc is characteristic of subacromial pain involving the rotator cuff, particularly supraspinatus and adjacent bursal tissues. Dynamic compression beneath the coracoacromial arch increases during elevation.
When septic arthritis is suspected clinically, particularly with fever, inability to bear weight, marked painful restriction or elevated inflammatory markers.

Investigations and diagnostic interpretation

Arthrocentesis provides direct assessment for crystals and infection. Normal temperature or peripheral white cell count does not exclude septic arthritis. Send fluid for cell count/differential, polarised crystal microscopy, Gram stain and culture; obtain blood cultures when sepsis is suspected.
A displaced longitudinal meniscal fragment can flip into the intercondylar notch and mechanically block terminal knee extension. A true locked knee requires urgent orthopaedic evaluation, often with MRI and arthroscopic management.
A line along the superior femoral-neck border on AP radiograph; in SCFE it may fail to intersect the femoral-head epiphysis.
Synovial WBC/differential, polarised crystals, Gram stain and culture, plus blood cultures if clinically indicated.

Management and operative principles

Major lower-limb surgery and postoperative immobility increase venous thromboembolism risk. Sudden pleuritic pain, dyspnoea and tachycardia require prompt assessment for PE even when prophylaxis has been given.
Obtain cultures and aspirate promptly; do not delay resuscitation or urgent antibiotics in sepsis.
Keep the patient non-weight-bearing and obtain urgent orthopaedic review if SCFE is suspected.
A truly locked knee may indicate a displaced bucket-handle tear and needs urgent assessment.

Measurements, staging and thresholds

The superficial MCL is the main restraint to valgus opening, especially around 20–30 degrees of knee flexion. Isolated laxity at 30 degrees with stability in full extension suggests MCL injury without major combined capsular or cruciate disruption. MRI is reserved according to suspected associated injury and severity.
Perthes disease is idiopathic osteonecrosis of the developing femoral-head epiphysis, classically affecting children around 4–8 years. It presents with limp and hip, thigh or referred knee pain; progressive radiographic changes include sclerosis, fragmentation and reossification.
Grade I: pain with little laxity; grade II: partial tear with some opening but an endpoint; grade III: marked laxity.
Transient synovitis often occurs between ages 3 and 8 years following a viral illness.

Common examiner traps

Semitendinosus is also an extensor; the stem specifies principal powerful hip extensor to avoid a multiple-correct-option recall.
A normal early radiograph does not exclude septic arthritis; never diagnose transient synovitis solely from normal X-rays.
A lateral cyst is not necessarily a ganglion unrelated to the meniscus; inspect the meniscal substance on MRI.
A painful arc is not specific for tendon tear; it is a clinical sign of a broader subacromial pain syndrome.
A normal knee X-ray does not rule out SCFE; do not allow weight-bearing while the diagnosis is unresolved.

Rapid-recall exam pearls

Delayed swelling with mechanical catching is a meniscal clue; immediate haemarthrosis suggests major intra-articular injury.
Acute atraumatic shoulder pain plus amorphous supraspinatus calcification suggests hydroxyapatite deposition.
Passive block = mechanical locking; loss of active extension with passive range = extensor mechanism problem.
Afebrile child after URI, mild hip pain and preserved weight-bearing: consider transient synovitis.
Fever + refusal to bear weight + painful passive hip motion = septic arthritis until excluded.

Musculoskeletal infection

Overview. Suspected bone or joint infection requires timely aspiration or cultures, appropriate antibiotics and source control when indicated.

Topic map — key distinctions

Subtopic	Defining feature / key principle
Septic arthritis	Septic arthritis may coexist and demands urgent drainage when indicated.
Osteomyelitis	Staphylococcus aureus is the leading cause of acute haematogenous osteomyelitis across paediatric age groups.

1. Septic arthritis

Septic arthritis may coexist and demands urgent drainage when indicated.

2. Osteomyelitis

Staphylococcus aureus is the leading cause of acute haematogenous osteomyelitis across paediatric age groups. Microbiology and age-specific organisms guide antibiotics, ideally after blood cultures and appropriate sampling.

Paediatric osteomyelitis: Staphylococcus aureus most commonly.
Chronic osteomyelitis can cause secondary AA amyloidosis.

Clinical recognition and differential diagnosis

Chronic inflammatory or suppurative disease increases hepatic serum amyloid A production and can cause secondary AA amyloidosis. Amyloid deposits are extracellular, amorphous and Congo-red positive with characteristic apple-green birefringence.
Tissue typing by appropriate immunohistochemistry or mass spectrometry, with clinical and haematological assessment.
AA amyloidosis is associated with longstanding inflammation and chronic infection.

Investigations and diagnostic interpretation

MRI is sensitive for early marrow infection.

Common examiner traps

Do not automatically label all amyloid AL; identify the inflammatory versus plasma-cell context.
Salmonella association with sickle cell disease does not make it most common overall.

Rapid-recall exam pearls

Paediatric osteomyelitis: Staphylococcus aureus most commonly.
Chronic osteomyelitis can cause secondary AA amyloidosis.

Musculoskeletal tumours and soft-tissue lesions

Overview. A growing, deep or unexplained mass requires imaging and biopsy planning through a specialist pathway before unplanned excision.

1. Investigation and biopsy

MRI defines extent and guides sampling.
MRI is the preferred local staging modality for most extremity soft-tissue sarcomas.
Deep or >5-cm enlarging mass: specialist sarcoma MDT, MRI, planned core biopsy.

Investigations and diagnostic interpretation

Record biopsy approach so the tract can be included in resection.
Biopsy should be coordinated by the specialist sarcoma team.
Biopsy should follow specialist imaging and MDT planning.

Measurements, staging and thresholds

For a large deep suspicious soft-tissue tumour, planned image-guided core needle biopsy provides architecture and grading information while allowing the tract to be excised with definitive surgery.
Increasing size, deep location and size greater than 5 cm are sarcoma red flags.
Size over 5 cm, growth, and deep location raise suspicion for sarcoma.
Chest CT is commonly used to stage pulmonary metastases.

Common examiner traps

Never perform an unplanned “shell-out” excision of a suspicious large deep mass.
Never perform an unplanned “shell-out” of a suspicious 15-cm deep mass.

Rapid-recall exam pearls

Sarcoma biopsy is part of the definitive oncologic operation—not an isolated minor procedure.
Deep or >5-cm enlarging mass: specialist sarcoma MDT, MRI, planned core biopsy.

Musculoskeletal, joints and sports medicine

Overview. A structured orthopaedic examination links anatomical pain location to mechanical symptoms, inflammatory features and radiological abnormalities.

Topic map — key distinctions

Subtopic	Defining feature / key principle
Joint examination	Monosodium urate crystals are slender needles with strong negative birefringence under compensated polarised light.
Soft-tissue pathology	Ganglia are benign mucin-filled cystic lesions arising near joints or tendon sheaths.

1. Joint examination

Monosodium urate crystals are slender needles with strong negative birefringence under compensated polarised light. Joint aspiration confirms the crystal diagnosis and permits assessment for infection.

Facet joint degeneration can cause axial mechanical pain worsened by extension or rotation, because these movements load the posterior elements. The pattern is suggestive rather than pathognomonic; examination alone cannot confirm the facet as the pain generator.
Hallux rigidus is degenerative arthritis of the first MTP joint, leading to reduced dorsiflexion, dorsal impingement and osteophyte formation. Radiographs show characteristic osteoarthritic changes.
Ganglia are benign mucin-filled cystic lesions arising near joints or tendon sheaths. The dorsal wrist, often near the scapholunate region, is a classic location.
A joint can simultaneously have crystal disease and infection.
Posterior elbow fluctuance with preserved joint movement suggests olecranon bursitis rather than septic arthritis.
Never dismiss joint sepsis solely because crystals are found.

2. Soft-tissue pathology

Ganglia are benign mucin-filled cystic lesions arising near joints or tendon sheaths. The dorsal wrist, often near the scapholunate region, is a classic location.

Applied anatomy and pathology

Compression of descending corticospinal pathways in the cervical cord produces upper motor neurone signs below the lesion: spasticity, hyperreflexia, clonus and extensor plantar responses. At the level of compression, segmental lower motor neurone findings may coexist.
Rhabdomyolysis causes skeletal muscle necrosis and release of CK, myoglobin and intracellular electrolytes. Myoglobin can produce heme-positive urine with few RBCs and contribute to acute kidney injury, particularly with volume depletion.
The medial plantar nerve, a branch of the tibial nerve, supplies plantar sensation to the medial three and a half toes and adjacent sole. Tibial nerve compression within the tarsal tunnel may produce symptoms in this distribution.

Clinical recognition and differential diagnosis

Anti-CCP antibodies (ACPA) have high specificity for rheumatoid arthritis and can precede clinical disease. They are associated with a greater likelihood of erosive disease, although a negative result does not exclude RA.
The infrapatellar branch crosses the anteromedial knee and is vulnerable to arthroscopy portals and medial incisions. Injury produces a local sensory deficit or painful neuroma without quadriceps weakness.
Facet pain is often axial and may refer to buttock or thigh without dermatomal deficit.

Investigations and diagnostic interpretation

Clinical diagnosis uses symptoms, examination, inflammatory markers and imaging, not serology alone.
Bursal aspirate for Gram stain, bacterial culture, cell count/differential and crystal microscopy.
Synovial-fluid Gram stain, culture and cell count, alongside clinical assessment.
Investigate secondary causes when clinical features or blood tests are atypical.

Management and operative principles

Aspiration can recur; surgery is considered for persistent symptomatic lesions.

Measurements, staging and thresholds

Herring classification is applied during fragmentation, not reliably in the earliest stage.
Group A: intact lateral pillar; B: more than 50% retained; C: less than 50% retained.
DXA T-score ≤ −2.5 defines osteoporosis in appropriate adults.
T-score of −2.5 or lower at an accepted skeletal site.

Common examiner traps

Do not confuse osteoporosis with osteomalacia, where vitamin D/phosphate abnormalities may be present.
Absence of fever does not exclude septic bursitis; examine for warmth, skin breaks and risk factors.
Do not confuse plantar digital sensation with the deep fibular nerve’s first dorsal web space.
Never assume a volar-radial wrist mass is a harmless ganglion without checking for pulsation.
Chronic gout can coexist with osteoarthritis; use the clinical and radiographic pattern.

Rapid-recall exam pearls

Posterior elbow fluctuance with preserved joint movement suggests olecranon bursitis rather than septic arthritis.
Cervical cord compression produces hyperreflexia and Babinski responses below the lesion.
Extension-provoked axial back pain suggests posterior-element/facet pathology.
Anteromedial knee numbness after arthroscopy = infrapatellar saphenous branch.
Most typical dorsal wrist fluctuant swelling in a young adult = ganglion.

Peripheral nerve lesions and clinical anatomy

Overview. Peripheral nerve localisation depends on combined motor, sensory and reflex findings rather than a single named muscle.

Topic map — key distinctions

Subtopic	Defining feature / key principle
Motor and sensory patterns	The superficial fibular nerve supplies fibularis longus and brevis for eversion and most dorsal-foot skin.

1. Motor and sensory patterns

The superficial fibular nerve supplies fibularis longus and brevis for eversion and most dorsal-foot skin. Preserved ankle dorsiflexion and first-web-space sensation indicate that the deep fibular branch is functioning, localising the lesion to the superficial branch.

Superficial fibular nerve: motor to fibularis longus/brevis; eversion.
Superficial fibular nerve supplies much of the dorsum of the foot, excluding key territories of the deep and sural nerves.
Common fibular nerve injury at the neck of fibula affects both branches and can cause foot drop.
Deep fibular nerve: anterior compartment; dorsiflexion and first-web-space sensation.
Weak eversion with preserved dorsiflexion = superficial fibular nerve lesion.

Common examiner traps

Foot drop indicates deep or common fibular involvement, not isolated superficial fibular nerve injury.

Rapid-recall exam pearls

Weak eversion with preserved dorsiflexion = superficial fibular nerve lesion.

Spine and nerve compression

Overview. Spinal symptoms are localised by root level, objective neurological deficit and red flags for cord or cauda equina compression.

Topic map — key distinctions

Subtopic	Defining feature / key principle
Lumbar and cauda equina	Lumbar canal stenosis narrows the space available for cauda equina nerve roots.
Imaging and surgery	New neurological deficits and bladder dysfunction in a patient with spinal metastases are red flags for metastatic spinal cord compression.

1. Lumbar and cauda equina

Lumbar canal stenosis narrows the space available for cauda equina nerve roots. Lumbar extension worsens neural compression during standing and downhill walking; flexion increases canal dimensions, relieving neurogenic claudication. The shopping-trolley sign is characteristic.

Flexion increases lumbar canal and foraminal dimensions.

2. Imaging and surgery

New neurological deficits and bladder dysfunction in a patient with spinal metastases are red flags for metastatic spinal cord compression. This is an oncological emergency requiring immediate specialist coordination, urgent whole-spine MRI (within 24 hours), appropriate immobilisation and corticosteroid treatment when indicated.

Urgent MRI is indicated for cauda equina red flags or progressive severe deficit.
Pelvic radiograph and, if appropriate, MRI of sacroiliac joints.
NICE NG234 recommends MRI within 24 hours for suspected MSCC.
Cancer + new weakness or sphincter symptoms = urgent whole-spine MRI.

Applied anatomy and pathology

Associated conditions include anterior uveitis, psoriasis and IBD.
L4: quadriceps strength, medial leg sensation and patellar reflex.

Clinical recognition and differential diagnosis

L5 radiculopathy produces weakness of extensor hallucis longus and sensory symptoms over the dorsum of the foot, including the first web space. Patellar (mainly L3–L4) and Achilles (mainly S1) reflexes can remain normal. A typical posterolateral L4–L5 disc herniation compresses the traversing L5 root.
Call the MSCC coordinator immediately when neurological red flags are present.
Inflammatory pain often improves with exercise rather than rest.

Investigations and diagnostic interpretation

Inflammatory back pain beginning before age 45, improving with activity, and restricted spinal mobility suggests axial spondyloarthritis. Imaging of sacroiliac joints and clinical assessment help classify radiographic versus non-radiographic disease.
Assess pulses and consider coexistent vascular disease.
Assess spinal stability and avoid unsafe mobilisation.

Management and operative principles

Urgent multidisciplinary assessment for decompression/stabilisation or radiotherapy, according to neurological status, stability and prognosis.
Progressive neurological deficits or cauda equina symptoms warrant urgent assessment.

Measurements, staging and thresholds

Dexamethasone 16 mg daily is generally recommended for neurological signs of MSCC pending definitive treatment, with clinical review.

Common examiner traps

Both vascular and neurogenic claudication occur with walking; posture-dependent relief is the key distinction.
At L4–L5, a posterolateral disc usually compresses the traversing L5 root, not the exiting L4 root.
Do not reassure yourself because vertebral lesions are osteosclerotic rather than lytic.

Rapid-recall exam pearls

Young adult + inflammatory back pain + reduced chest expansion = axial spondyloarthritis.
Walking-induced leg symptoms relieved by spinal flexion = neurogenic claudication.
Weak great-toe extension with first-web-space sensory loss localises to L5.
Cancer + new weakness or sphincter symptoms = urgent whole-spine MRI.

Perioperative & Critical Care

Perioperative pharmacology and dosing

Overview. Perioperative prescribing must respect body weight, organ function, age and drug interactions; dosage errors can cause preventable harm.

Topic map — key distinctions

Subtopic	Defining feature / key principle
Weight-based dosing	At 15 mg/kg, one dose is 20 × 15 = 300 mg.

1. Weight-based dosing

At 15 mg/kg, one dose is 20 × 15 = 300 mg. Four doses total 1,200 mg in 24 hours, equivalent to 60 mg/kg/day. This is a calculation under the stated regimen, not a universal maximum for every route, age or national formulary.

Four 300-mg doses total 1,200 mg = 60 mg/kg/day.
Weight-based dose: 15 mg/kg × 20 kg = 300 mg.
For a specified 15 mg/kg four-dose regimen, the 24-hour total is 60 mg/kg.
Do not apply 60 mg/kg/day as a universal ceiling across all routes and ages, or forget combination cold remedies containing paracetamol.

Measurements, staging and thresholds

12.5 mL; confirm the actual product strength and age-specific formulary.

Common examiner traps

Do not apply 60 mg/kg/day as a universal ceiling across all routes and ages, or forget combination cold remedies containing paracetamol.

Rapid-recall exam pearls

For a specified 15 mg/kg four-dose regimen, the 24-hour total is 60 mg/kg.

Perioperative physiology and emergencies

Overview. Anaesthetic and perioperative care anticipates respiratory, haemodynamic, endocrine and metabolic disturbances before decompensation.

Topic map — key distinctions

Subtopic	Defining feature / key principle
Respiratory and cardiovascular physiology	Intramuscular adrenaline is the first-line treatment for anaphylaxis.
Anaphylaxis and adverse drug reaction	Intramuscular adrenaline is the first-line treatment for anaphylaxis.
Thermoregulation	NICE CG65 defines perioperative hypothermia as core temperature below 36.0°C.

1. Respiratory and cardiovascular physiology

Intramuscular adrenaline is the first-line treatment for anaphylaxis. In adults, the standard dose is 500 micrograms (0.5 mL of 1 mg/mL, 1:1000) into the mid-anterolateral thigh, with immediate ABC management, help, oxygen and IV fluids as indicated.

2. Anaphylaxis and adverse drug reaction

Adult anaphylaxis: adrenaline 0.5 mg IM, 1:1000, lateral thigh.
Refractory anaphylaxis under experienced critical-care supervision.

3. Thermoregulation

NICE CG65 defines perioperative hypothermia as core temperature below 36.0°C. Recovery-room temperature should be documented on admission and at 15-minute intervals; ward transfer should not be arranged until it is 36.0°C or higher. Forced-air warming is appropriate when below that threshold.

Hypothermia can increase shivering, coagulopathy and wound complications.

Clinical recognition and differential diagnosis

ERAS pathways aim to reduce perioperative stress, complications and length of stay and promote early recovery. They do not guarantee prevention of chronic postsurgical pain, which has multiple mechanisms and risk factors.
Chronic postsurgical pain can still occur despite ERAS compliance.

Measurements, staging and thresholds

BOASt recommends an adult upper-limb tourniquet pressure of systolic blood pressure plus 50–100 mmHg when using the SBP method. With SBP 130 mmHg, the appropriate range is 180–230 mmHg; 200 mmHg is within that range. Use the lowest effective pressure with a suitable cuff, timer and documentation.
The three qSOFA bedside features are respiratory rate at least 22/min, systolic blood pressure at most 100 mmHg, and altered mental status (GCS below 15). Each scores one point. qSOFA is a risk prompt and should not be used alone to rule out sepsis.
Use clinical judgement and appropriate early-warning tools; a low qSOFA score does not exclude sepsis.
Aim for ischaemic time below 120 minutes; extensions require documented risk–benefit assessment.

Common examiner traps

A fixed 250–300 mmHg is not automatically appropriate for every patient; cuff fit and local policy matter.
Do not confuse the minimum safe transfer threshold with normal thermoregulation around 36.5–37.5°C.
A scar becoming pale reflects vascular regression, not impaired perfusion requiring treatment.
The systolic threshold is ≤100 mmHg, not <90 mmHg; qSOFA is not the definition of sepsis.
Do not confuse IM 1:1000 adrenaline with IV 1:10,000 cardiac-arrest dosing.

Rapid-recall exam pearls

For an adult upper limb, use SBP plus 50–100 mmHg under the BOASt SBP-based approach.
A two-month-old scar is mainly remodelling, not clotting or acute inflammation.
ERAS supports faster recovery but cannot guarantee absence of chronic pain.
NICE recovery-room ward-transfer temperature is at least 36.0°C.
Adult anaphylaxis: adrenaline 0.5 mg IM, 1:1000, lateral thigh.

Postoperative complications and wound care

Overview. Postoperative deterioration requires systematic assessment for haemorrhage, infection, thromboembolism, organ dysfunction and wound complications.

Topic map — key distinctions

Subtopic	Defining feature / key principle
Wound infection and healing	Fascial wound dehiscence often occurs around postoperative days 5–10 due to failure of fascial healing, sometimes heralded by sudden pink serous or serosanguinous fluid.

1. Wound infection and healing

Fascial wound dehiscence often occurs around postoperative days 5–10 due to failure of fascial healing, sometimes heralded by sudden pink serous or serosanguinous fluid. It is a surgical emergency because viscera may eviscerate.

Management and operative principles

Urgently resuscitate and obtain surgical management.

Common examiner traps

Do not mistake deep dehiscence for a harmless superficial seroma.

Rapid-recall exam pearls

Sudden salmon-pink discharge on day 5–10 is a warning of burst abdomen.

Skin, Head & Neck

Dermatology and cutaneous oncology

Overview. Skin lesions are classified by morphology, growth and histology; nonhealing or atypical lesions require biopsy and appropriate margins.

Topic map — key distinctions

Subtopic	Defining feature / key principle
Keratinocyte cancer	Cutaneous SCC more commonly has metastatic potential than conventional BCC, although aggressive BCC subtypes require careful management.
Melanoma	Breslow thickness measures melanoma depth from the epidermal granular layer (or ulcer base when ulcerated) to the deepest invasive tumour cell.
Excision and surveillance	Excisional biopsy with a narrow margin is preferred when feasible for initial diagnosis.

1. Keratinocyte cancer

Cutaneous SCC more commonly has metastatic potential than conventional BCC, although aggressive BCC subtypes require careful management.

Everted ulcer edge and keratin pearls favour SCC; the original recall mixed these with basaloid clues.
Peripheral palisading and tumour–stromal retraction clefts support BCC histology.
BCC is strongly associated with chronic ultraviolet exposure.
Basaloid nests + peripheral palisading + stromal cleft = BCC.

2. Melanoma

Breslow thickness measures melanoma depth from the epidermal granular layer (or ulcer base when ulcerated) to the deepest invasive tumour cell. It is a principal component of melanoma T classification, together with ulceration. It guides excision margins and discussion of sentinel lymph-node biopsy.

Breslow thickness strongly predicts melanoma outcome.
For invasive melanoma, Breslow thickness is a core staging measurement.
Pigmented melanoma can mimic seborrhoeic keratosis, so atypical lesions need evaluation.
Breslow thickness is reported in millimetres.
Clark level is historically important but is not a substitute for Breslow thickness in contemporary staging.

3. Excision and surveillance

Excisional biopsy with a narrow margin is preferred when feasible for initial diagnosis.

Complete full-thickness excisional biopsy with a narrow margin, commonly around 2 mm, preserves architecture and enables accurate Breslow-depth assessment. Definitive wide local excision margin is determined after histological staging.
Suspected melanoma → narrow full-thickness excision first, definitive margins after histology.
Treatment may include excision or other local destructive techniques with histology when indicated.
Breslow thickness measures melanoma depth from the epidermal granular layer (or ulcer base when ulcerated) to the deepest invasive tumour cell. It is a principal component of melanoma T classification, together with ulceration. It guides excision margins and discussion of sentinel lymph-node biopsy.
A 2-cm wide excision is not usually the initial diagnostic procedure.

Applied anatomy and pathology

Squamous-cell carcinoma arising in a longstanding scar or chronic wound, classically a burn scar.
A chronic wound can develop squamous malignancy, but not every venous ulcer is a Marjolin ulcer.
Typical venous ulcers are often shallow, irregular and located in the medial gaiter region.

Clinical recognition and differential diagnosis

Kaposi sarcoma is associated with human herpesvirus 8 (HHV-8/KSHV), a gammaherpesvirus that drives vascular spindle-cell proliferation, especially in immunosuppressed hosts.
Dermatofibroma is a benign fibrohistiocytic lesion, often on the lower limbs, with a firm dermal nodule and characteristic dimple sign from dermal tethering.
Diagnosis requires tissue assessment when clinically uncertain.

Investigations and diagnostic interpretation

Marjolin ulcer describes malignant transformation arising in chronic scars, nonhealing wounds or longstanding inflammatory lesions, especially old burn scars. The most common histological type is squamous-cell carcinoma. Any new ulceration, nodularity or bleeding in a chronic scar warrants prompt biopsy.
Basal-cell carcinoma characteristically contains nests of basaloid cells with peripheral palisading and stromal retraction clefts. The added biopsy findings resolve the original contradictory recall, which combined everted-edge SCC clues with “basaloid” features.
Duplex ultrasound, pulse-volume recordings and transcutaneous oxygen pressure as clinically appropriate.
Sentinel-node biopsy decisions incorporate tumour thickness and other risk factors.

Measurements, staging and thresholds

Obtain a representative biopsy of the suspicious lesion; staging and definitive resection follow histological confirmation.
Sentinel node biopsy decisions depend on staging and risk.
Ulceration independently affects T staging.

Common examiner traps

Clark level is historically important but is not a substitute for Breslow thickness in contemporary staging.
Everted ulcer edge and keratin pearls favour SCC; the original recall mixed these with basaloid clues.
Do not assume every rapidly growing bleeding lesion is benign without appropriate assessment.
Pigmented melanoma can mimic seborrhoeic keratosis, so atypical lesions need evaluation.
Do not dismiss a newly ulcerating old scar as simple recurrent trauma or infection.

Rapid-recall exam pearls

Suspected melanoma → narrow full-thickness excision first, definitive margins after histology.
Fast-growing, red, friable and bleeding after trauma = pyogenic granuloma.
Chronic burn scar + new indurated ulcer = Marjolin ulcer (usually SCC).
For invasive melanoma, Breslow thickness is a core staging measurement.
Atypical or non-healing ulcer with indurated raised edges: biopsy.

ENT infections and airway

Overview. The available recall in this section principally addresses tracheostomy landmarks rather than an ENT infection; the notes therefore focus on the supported airway anatomy.

Topic map — key distinctions

Subtopic	Defining feature / key principle
Elective tracheostomy landmarks	The cricoid cartilage is a reliable palpable superior landmark for an elective cervical tracheostomy incision, with the incision commonly centred between the cricoid and suprasternal notch.
Cricothyrotomy distinction	An emergency front-of-neck airway is usually via the cricothyroid membrane, not a formal low tracheostomy.
Structures at risk	The cricoid cartilage is a reliable palpable superior landmark for an elective cervical tracheostomy incision, with the incision commonly centred between the cricoid and suprasternal notch.

1. Elective tracheostomy landmarks

The cricoid cartilage is a reliable palpable superior landmark for an elective cervical tracheostomy incision, with the incision commonly centred between the cricoid and suprasternal notch. The tracheal opening is typically made at approximately the second to fourth tracheal rings, avoiding injury to the cricoid and first ring.

Planned tracheostomy incision: midline between cricoid and suprasternal notch.
An emergency front-of-neck airway is usually via the cricothyroid membrane, not a formal low tracheostomy.
A standard tracheostomy enters the trachea below the first ring.
Do not confuse planned tracheostomy with emergency cricothyrotomy.

2. Cricothyrotomy distinction

An emergency front-of-neck airway is usually via the cricothyroid membrane, not a formal low tracheostomy.

3. Structures at risk

The thyroid isthmus may overlie rings 2–4.

Common examiner traps

Do not confuse planned tracheostomy with emergency cricothyrotomy.

Rapid-recall exam pearls

Planned tracheostomy incision: midline between cricoid and suprasternal notch.

ENT, oral and head-neck disorders

Overview. Symptoms in the oral cavity, pharynx, salivary glands and neck require targeted examination and assessment for infection, structural obstruction or malignancy.

Topic map — key distinctions

Subtopic	Defining feature / key principle
Ear and sinonasal disease	Chronic nasolacrimal duct obstruction causes tear stasis and recurrent inflammation of the lacrimal sac.
Oral lesions and cancer	The sigmoid sinus courses in a groove on the medial surface of the mastoid temporal bone.
Neck masses and glands	In adults, a new lateral cystic neck mass requires malignancy exclusion.
Airway and swallowing	Inability to swallow saliva, stridor, neck swelling or crepitus requires emergency escalation.

1. Ear and sinonasal disease

Chronic nasolacrimal duct obstruction causes tear stasis and recurrent inflammation of the lacrimal sac. Epiphora, a swelling below the medial canthal tendon and reflux of mucopurulent material through a punctum on sac compression are characteristic. Normal ocular motility and vision make orbital cellulitis less likely.

The maxillary sinus opens into the middle meatus via an ostium located high on its medial wall. Drainage therefore depends on mucociliary clearance rather than simple gravity, and obstruction of the ostiomeatal complex promotes retained secretions and infection.
Symptoms can mimic chronic rhinosinusitis early.
Acquired cholesteatoma consists of keratinising squamous epithelium accumulating in the middle ear or mastoid, often through a pars flaccida retraction pocket. It may erode ossicles and adjacent bone, causing conductive hearing loss and persistent offensive discharge.
Acute middle-ear infection raises pressure behind the tympanic membrane. A spontaneous perforation releases purulent material into the external auditory canal, often relieving pressure and pain. The child still needs assessment for ongoing infection and complications.
Cholesteatoma consists of keratinising squamous epithelium in the middle ear and can erode adjacent bone. The incus is frequently affected, especially its long process, producing ossicular discontinuity and conductive hearing loss. The condition also risks facial nerve, labyrinthine and intracranial complications.
Definitive treatment usually requires surgical clearance and surveillance for residual or recurrent disease.

2. Oral lesions and cancer

The sigmoid sinus courses in a groove on the medial surface of the mastoid temporal bone. Otomastoid infection can spread to cause septic sigmoid (lateral) sinus thrombosis, an important intracranial complication.

A persistent indurated oral ulcer, especially on the lateral tongue in a patient with tobacco and alcohol exposure, is suspicious for oral squamous-cell carcinoma. Histological sampling is required for diagnosis; subsequent imaging and nodal assessment stage confirmed disease.
Persistent indurated oral ulcer: urgent biopsy to exclude SCC.
Transoral surgery with neck dissection and risk-adapted adjuvant therapy is an alternative in selected patients.
Transoral resection and appropriate neck surgery, followed by risk-adapted adjuvant therapy.
High-resolution temporal-bone CT and diffusion-weighted MRI may aid specialist assessment.
High-resolution temporal-bone CT may help define bony extent before surgery.

3. Neck masses and glands

In adults, a new lateral cystic neck mass requires malignancy exclusion.
Posterior-triangle transilluminant multiloculated neck mass in infancy = lymphatic malformation.
A rapidly enlarging neck mass without imaging details is nonspecific; this is a reconstructed discriminating vignette.
Do not perform blind needle biopsy of a hypervascular neck mass.

4. Airway and swallowing

Inability to swallow saliva, stridor, neck swelling or crepitus requires emergency escalation.

Severe stridor mandates an airway rescue plan before instrumentation.
Delayed stridor after prolonged intubation = consider subglottic/tracheal stenosis.
Pressure-related ischaemia from an endotracheal tube can lead to mucosal injury, granulation and circumferential fibrosis. The resulting fixed narrowing may cause delayed exertional dyspnoea and stridor, sometimes mistaken for asthma. Stridor at rest requires urgent specialist airway evaluation.

Applied anatomy and pathology

The nasociliary nerve is a branch of ophthalmic trigeminal nerve (V1). Its long ciliary branches convey corneal sensation and its external nasal branch supplies the nasal tip. A proximal nasociliary lesion can affect both territories.
A macrocystic lymphatic malformation consists of abnormal lymphatic channels forming large cystic spaces, classically in the posterior cervical triangle. It can enlarge after infection or haemorrhage and may compromise the airway.
A second branchial cleft anomaly commonly presents as a lateral neck cyst along the anterior border of sternocleidomastoid. Intercurrent infection can cause rapid enlargement or tenderness.

Clinical recognition and differential diagnosis

The roots of the upper premolars and molars lie close to the floor of the maxillary sinus, sometimes separated by only thin bone. Dental infection or extraction can create odontogenic maxillary sinusitis or an oroantral communication. Unilateral purulent discharge and cheek/upper-tooth pain support this location.
Retropharyngeal lymph nodes are prominent in young children and can suppurate following upper respiratory infection. Fever, neck stiffness or torticollis, dysphagia and airway symptoms are characteristic; airway assessment is the immediate priority.
Nasopharyngeal carcinoma can obstruct the pharyngeal opening of the Eustachian tube, producing unilateral otitis media with effusion. Cervical nodal metastases are common; Epstein–Barr virus is associated with many non-keratinising cases.

Investigations and diagnostic interpretation

Vestibular schwannoma arises from Schwann cells of the vestibular division of CN VIII and commonly presents with asymmetric sensorineural hearing loss, unilateral tinnitus and imbalance. MRI of the internal auditory canals/cerebellopontine angles is the key imaging test.
Persistent oesophageal symptoms after a suspected fish-bone ingestion warrant urgent endoscopic evaluation despite negative radiography. CT may help localise a bone or evaluate suspected perforation, but it must not delay urgent specialist management of an impacted sharp object.
FDG PET-CT can detect metabolically active occult primaries and distant spread in selected patients with cervical metastatic squamous cancer. Imaging complements careful clinical examination, cross-sectional imaging and directed endoscopy/biopsy.
Long-term occupational hardwood-dust exposure is strongly associated with sinonasal intestinal-type adenocarcinoma, especially in the ethmoid region. Persistent unilateral bloody nasal symptoms warrant urgent endoscopic evaluation and imaging.

Management and operative principles

The maxillary sinus ostium is located relatively superiorly on its medial wall and opens into the middle meatus. Drainage depends mainly on mucociliary transport, and obstruction of the ostiomeatal complex predisposes to retained secretions and sinusitis.
Toxigenic Corynebacterium diphtheriae causes a tough pharyngeal pseudomembrane and can produce systemic toxin-mediated myocarditis and neuropathy. Suspected cases need urgent isolation, public-health action, antitoxin assessment and antibiotics.
Cholesteatoma can erode ossicles, mastoid and the bony facial canal, leading to facial nerve palsy and intracranial complications. New facial weakness with chronic otorrhoea warrants urgent specialist assessment.
The posterior ethmoidal air cells drain into the superior meatus beneath the superior concha. Anterior and middle ethmoidal cells drain more anteriorly, while the sphenoid drains into the sphenoethmoidal recess.

Measurements, staging and thresholds

For appropriately selected locally advanced oropharyngeal SCC treated non-operatively, definitive radiation with concurrent cisplatin is a standard organ-preserving approach. Selection depends on stage, nodal burden, performance status and cisplatin suitability.
Erythroplakia is a persistent red oral mucosal patch not attributable to another definable condition. It carries a substantial likelihood of high-grade dysplasia or carcinoma on biopsy and warrants urgent specialist assessment and histology.
A destructive maxillary sinus tumour can invade the orbit, infraorbital nerve (V2), alveolar process and oral vestibule, producing proptosis, cheek anaesthesia and upper dental symptoms. Histological biopsy and staging are required.
Levels I–III, with additional levels depending on tumour location and stage.

Common examiner traps

Do not interpret historical T2N2a labels using modern HPV-positive staging, or claim chemoradiotherapy is the only valid MDT approach.
A rapidly enlarging neck mass without imaging details is nonspecific; this is a reconstructed discriminating vignette.
A cystic cervical node from metastatic HPV-associated oropharyngeal carcinoma may mimic a branchial cyst in adults.
Anterior gastric perforation usually causes free peritoneal contamination; posterior perforation may be contained.
Chronic discharge alone does not establish cholesteatoma; the otoscopic keratin/retraction findings are decisive.

Rapid-recall exam pearls

Locally advanced HPV-positive oropharyngeal SCC can be treated with definitive cisplatin-based chemoradiotherapy.
Hardwood worker + unilateral bloody nasal obstruction = suspect ethmoid intestinal-type adenocarcinoma.
Medial-canthal sac swelling + epiphora + punctal mucous reflux = dacryocystitis/duct obstruction.
Posterior-triangle transilluminant multiloculated neck mass in infancy = lymphatic malformation.
Chronic foul ear discharge + new facial palsy = urgent cholesteatoma complication assessment.

Oral cavity and head-neck oncology

Overview. Persistent mucosal ulceration or cervical lymphadenopathy may represent head-and-neck cancer and requires tissue diagnosis plus anatomical staging.

Topic map — key distinctions

Subtopic	Defining feature / key principle
Oral squamous carcinoma	Tobacco use is a major established risk factor for oral cavity squamous-cell carcinoma, with synergistic risk from alcohol.
Lymphatic drainage and staging	A translucent posterior-triangle neonatal neck mass suggests lymphatic malformation.
Imaging and treatment	Tobacco use is a major established risk factor for oral cavity squamous-cell carcinoma, with synergistic risk from alcohol.

1. Oral squamous carcinoma

Tobacco use is a major established risk factor for oral cavity squamous-cell carcinoma, with synergistic risk from alcohol. A persistent indurated tongue ulcer with cervical lymphadenopathy requires oncological staging and management. HPV is particularly important in oropharyngeal cancers, especially tonsillar and base-of-tongue disease, rather than all oral tongue cancers.

The lateral tongue and floor of mouth are common oral cavity SCC sites.
Occult SCC in bilateral upper cervical nodes should prompt careful oropharyngeal assessment.
Oral cavity SCC: tobacco/alcohol; HPV association is strongest in the oropharynx.
Unknown-primary cervical SCC is a head-and-neck MDT problem.

2. Lymphatic drainage and staging

A translucent posterior-triangle neonatal neck mass suggests lymphatic malformation.

Unknown-primary cervical SCC is a head-and-neck MDT problem.

3. Imaging and treatment

Ultrasound is a usual first-line test; MRI defines deeper extent and relation to vital structures.
CT or MRI supplies detailed local anatomy.
A structured personal and family bleeding history is more useful than indiscriminate PT/APTT screening for detecting clinically important bleeding disorders in low-risk children. Targeted testing is appropriate if history, examination or a known disorder raises concern.
Peritonsillar abscess produces unilateral palatal swelling, trismus, odynophagia and deviation of the uvula away from the affected side. Management requires airway assessment, analgesia, appropriate antibiotics and drainage when indicated.
A focused bleeding history is more useful than universal coagulation testing for identifying children who require further assessment before tonsillectomy. Testing is guided by symptoms, family history, medication and comorbidity.

Applied anatomy and pathology

HPV-related cancer is classically oropharyngeal rather than anterior oral tongue.
Trismus reflects irritation of adjacent pterygoid musculature.

Clinical recognition and differential diagnosis

A cervical lymphatic malformation represents abnormally developed lymphatic channels, which form thin-walled cystic spaces. Large macrocystic lesions often present at birth, may transilluminate and can compromise the airway.
Nasopharyngeal carcinoma can obstruct the pharyngeal opening of the Eustachian tube, producing unilateral otitis media with effusion and conductive loss. Cervical nodal metastases are common at presentation.
HPV-related oropharyngeal tumours commonly present with cervical nodes.

Investigations and diagnostic interpretation

FDG PET-CT may identify occult mucosal primaries and distant disease when initial examination and imaging are unrevealing. Specialist endoscopic assessment and appropriately targeted biopsies remain essential.
Management may include image-guided sclerotherapy and/or surgery in a specialist multidisciplinary team.
Persistent induration, ulceration and cervical nodes are red flags requiring biopsy.
p16 immunohistochemistry, interpreted in the clinical and pathology context.

Management and operative principles

Take a detailed bleeding history including epistaxis, bruising, surgery and dental bleeding.
Needle aspiration or incision and drainage plus antibiotics when indicated.
Level II upper cervical nodes commonly drain the oropharynx.

Measurements, staging and thresholds

Biopsy and imaging establish diagnosis and stage.

Common examiner traps

A negative simple oral examination does not exclude a small tonsillar crypt or tongue-base primary.
Do not equate anterior oral tongue cancer with HPV-driven base-of-tongue (oropharyngeal) carcinoma.
Do not assume all unilateral effusions in adults are benign Eustachian tube dysfunction.
Cellulitis can mimic abscess; aspiration or imaging may be needed in uncertain cases.
Large lesions may extend into the mediastinum; do not assume a superficial cyst.

Rapid-recall exam pearls

Occult SCC in bilateral upper cervical nodes should prompt careful oropharyngeal assessment.
Unilateral adult conductive hearing loss plus cervical nodes raises nasopharyngeal cancer.
Negative structured bleeding history in a healthy child → no universal PT/aPTT screening.
Negative structured bleeding history in healthy child: no blanket coagulation screen.
A translucent posterior-triangle neonatal neck mass suggests lymphatic malformation.

Salivary gland disease

Overview. Salivary gland swellings are distinguished by relation to meals, infection, nerve involvement and malignant features.

Topic map — key distinctions

Subtopic	Defining feature / key principle
Tumours	Pleomorphic adenoma is the commonest benign salivary gland neoplasm and classically presents as a slow-growing painless parotid lump without facial nerve deficit.
Anatomy and investigation	Acute suppurative bacterial parotitis produces a tender swollen parotid gland with fever and may cause pus to drain from Stensen duct on massage.

1. Tumours

Pleomorphic adenoma is the commonest benign salivary gland neoplasm and classically presents as a slow-growing painless parotid lump without facial nerve deficit. Imaging and cytology or core biopsy help establish diagnosis; planned parotid surgery should preserve the facial nerve and avoid simple enucleation because of pseudopod extensions and recurrence risk.

Painless slow-growing parotid mass with intact facial nerve = pleomorphic adenoma is likely.
Do not enucleate pleomorphic adenoma; use appropriate gland-preserving oncological planes.
Pleomorphic adenoma is a benign epithelial–myoepithelial mixed tumour.

2. Anatomy and investigation

Acute suppurative bacterial parotitis produces a tender swollen parotid gland with fever and may cause pus to drain from Stensen duct on massage. Dehydration and reduced salivary flow are important predispositions. Staphylococcus aureus is a frequent pathogen, although other bacteria can occur. The original fever/preauricular swelling alone could not distinguish bacterial from viral causes.

Stensen duct opens in the buccal mucosa opposite the maxillary second molar.
Pus from Stensen duct on parotid massage strongly supports acute bacterial parotitis.

Applied anatomy and pathology

The oral tongue commonly drains to submental/submandibular and upper or middle jugular nodes (levels I–III). A node near the angle of the mandible along the upper internal jugular chain is level II. This is a frequent regional metastatic basin for oral tongue squamous-cell carcinoma.
A lesion close to or crossing the midline, advanced size or deeper invasion.
Lateral oral tongue lesions commonly spread to ipsilateral levels I–III.

Clinical recognition and differential diagnosis

Mumps is a paramyxovirus infection classically producing painful parotitis, sometimes bilateral, with fever and malaise.
Facial weakness in a parotid mass is a red flag for malignancy.

Investigations and diagnostic interpretation

Obtain ductal pus for culture where feasible and assess for abscess or deep neck infection.
Ultrasound and MRI may help delineate a large or plunging lesion.

Management and operative principles

Treat ocular and oral dryness and monitor complications.

Measurements, staging and thresholds

Neck assessment and management are central to oral cavity SCC staging.

Common examiner traps

Pain and fever alone are insufficient to choose mumps or bacterial parotitis; the duct examination provides the discriminator.
Do not confuse oral tongue lymphatic drainage with posterior tongue/base-of-tongue oropharyngeal cancer patterns.
Long duration does not exclude malignant transformation; assess growth acceleration and nerve function.
Parotid swelling in Sjögren warrants evaluation for lymphoma if persistent or asymmetric.
Distinguish parotid gland swelling from isolated preauricular lymphadenopathy.

Rapid-recall exam pearls

Painless slow-growing parotid mass with intact facial nerve = pleomorphic adenoma is likely.
Pus from Stensen duct on parotid massage strongly supports acute bacterial parotitis.
Upper deep cervical node at the angle of the mandible = level II.
Fever with painful preauricular parotid swelling suggests mumps.
Dry eyes + dry mouth + RA = secondary Sjögren syndrome.

Skin and soft tissue infection

Overview. Soft-tissue sepsis is managed by recognising a drainable focus and assessing for systemic toxicity; superficial cellulitis differs from an abscess and necrotising infection.

Topic map — key distinctions

Subtopic	Defining feature / key principle
Pilonidal disease	Pilonidal sinus disease is an acquired inflammatory condition of the natal cleft associated with hair penetration and local friction.
Abscess drainage	Fluctuant collection requires incision and drainage, followed by reassessment of chronic sinus disease.

1. Pilonidal disease

Pilonidal sinus disease is an acquired inflammatory condition of the natal cleft associated with hair penetration and local friction. Midline pits and hair-containing sinus tracts are characteristic; lateral secondary openings can occur in more complex disease. Acute pilonidal abscess is managed with drainage, whereas chronic disease management considers symptoms, hair control and appropriate definitive procedures.

Pilonidal disease commonly occurs in the sacrococcygeal natal cleft.
Natal cleft + midline hair-containing pits = pilonidal disease.

2. Abscess drainage

Fluctuant collection requires incision and drainage, followed by reassessment of chronic sinus disease.

Applied anatomy and pathology

A lateral secondary opening can indicate complex sinus disease.

Clinical recognition and differential diagnosis

Diabetes, immunosuppression and disproportionate nocturnal pain raise concern for necrotising otitis externa.
Mastoiditis can produce a subperiosteal abscess with postauricular swelling and pinna displacement.
Lumbar puncture may be unsafe when intracranial mass effect is suspected.

Investigations and diagnostic interpretation

MRI with diffusion-weighted imaging helps differentiate pus from some necrotic tumours.
Pain with movement of the tragus or pinna is a characteristic examination finding.
CT temporal bone and/or MRI may be required depending on suspected complications.
Do not delay IV antibiotics for imaging in a systemically unwell child.

Management and operative principles

Chronic middle-ear or mastoid infection can spread contiguously to the temporal lobe or cerebellum. Fever, focal seizures and a ring-enhancing lesion with restricted diffusion are strongly suggestive of a brain abscess requiring urgent neurosurgical and ENT assessment.
Necrotising (malignant) otitis externa, often due to Pseudomonas, requiring urgent specialist assessment.
Management includes IV antimicrobials, source control and neurosurgical drainage when indicated.
Acute abscess requires drainage; antibiotics alone do not replace drainage.

Common examiner traps

Do not confuse otitis externa with acute otitis media; tympanic membrane integrity affects choice of ear drops.
Do not perform an indiscriminate lumbar puncture in a patient with possible intracranial abscess or raised ICP.
Meningeal signs can coexist; do not perform LP before assessing for mass effect.
Differentiate a natal-cleft sinus from an anal fistula with an internal opening.

Rapid-recall exam pearls

Fever, otitis, postauricular swelling and meningism require urgent IV treatment and ENT involvement.
Uncomplicated otitis externa is treated topically; routine oral antibiotics are unnecessary.
Chronic ear sepsis + seizures + ring lesion = suspect brain abscess.
Natal cleft + midline hair-containing pits = pilonidal disease.

Skin cancers, lesions and melanoma

Overview. Cutaneous cancers are classified by keratinocyte or melanocytic origin; lesion morphology and histological invasion determine treatment and surveillance.

Topic map — key distinctions

Subtopic	Defining feature / key principle
BCC and SCC	Basal cell carcinoma is a common locally invasive keratinocyte malignancy associated with ultraviolet exposure.
Melanoma staging	Melanoma in situ is confined to epidermis and does not invade dermal lymphatics.
Keratoacanthoma and mimics	Keratoacanthoma classically forms a rapidly enlarging crateriform nodule with a central keratin plug.
Biopsy and excision	Keloids represent excessive collagen deposition extending beyond the original wound margins, sometimes associated with itching, pain and recurrence after excision.

1. BCC and SCC

Basal cell carcinoma is a common locally invasive keratinocyte malignancy associated with ultraviolet exposure. Nodular lesions often show translucent pearly rolled edges and telangiectasia; ulceration may produce a rodent ulcer.

BCC has basaloid nests and peripheral palisading; SCC has atypical squamous cells and keratinisation.
Basal-cell carcinoma is a locally invasive keratinocyte cancer strongly linked to ultraviolet exposure. Its nodular subtype commonly presents as a pearly papule with surface telangiectasia and potential central ulceration.
SCC has malignant keratinocyte differentiation.
A fast-growing keratin-crater nodule suggests keratoacanthoma—but exclude SCC histologically.
Rapid crateriform keratin-plug nodule = keratoacanthoma pattern; treat as possible SCC.
Everted ulcer with keratin pearls and intercellular bridges is SCC.

2. Melanoma staging

Melanoma in situ is confined to epidermis and does not invade dermal lymphatics. Once excision margins are adequate, patient education, skin self-examination and risk-adjusted follow-up are appropriate.

Melanoma in situ without invasion requires adequate local excision, not nodal clearance.
Do not apply invasive melanoma sentinel-node rules to pure in-situ disease.
Common melanoma-in-situ clinical margins are approximately 5–10 mm depending on site and guidance.

3. Keratoacanthoma and mimics

Keratoacanthoma classically forms a rapidly enlarging crateriform nodule with a central keratin plug. Because it overlaps clinically and histologically with well-differentiated squamous cell carcinoma, a suspicious lesion should be sampled or excised rather than presumed harmless because spontaneous regression sometimes occurs.

Keratoacanthoma is a rapidly growing crateriform keratinising lesion that closely resembles well-differentiated cutaneous squamous carcinoma. Because clinical distinction is unreliable, histological assessment and appropriate excision are generally indicated.
A fast-growing keratin-crater nodule suggests keratoacanthoma—but exclude SCC histologically.
Rapid crateriform keratin-plug nodule = keratoacanthoma pattern; treat as possible SCC.
Cutaneous SCC can mimic keratoacanthoma and needs exclusion.
Keratoacanthoma may grow quickly over weeks.
Do not reassure solely because keratoacanthoma can regress; SCC can look identical.

4. Biopsy and excision

Keloids represent excessive collagen deposition extending beyond the original wound margins, sometimes associated with itching, pain and recurrence after excision.

A representative incisional or punch biopsy establishes histology and informs definitive excision margins and multidisciplinary planning for a large suspicious scalp lesion. The biopsy must include adequate dermis and, where needed, depth to assess invasion.
Melanoma in situ is confined to epidermis and does not invade dermal lymphatics. Once excision margins are adequate, patient education, skin self-examination and risk-adjusted follow-up are appropriate.
Assess regional nodes and high-risk features; treatment is usually complete excision with appropriate margins.
Definitive treatment commonly requires margin-controlled excision or specialist surgery.
High-risk locations and aggressive histology may require margin-controlled excision.
Excisional tissue should include the architectural base and margins where feasible.

Applied anatomy and pathology

The great majority of laryngeal malignancies are squamous cell carcinomas, reflecting the squamous mucosal lining and strong association with tobacco and alcohol exposure.
Keratin pearls, dysplastic squamous cells and intercellular bridges characterise a keratinising cutaneous squamous-cell carcinoma with dermal invasion.
Spontaneous involution may occur, but observation alone risks missing invasive squamous carcinoma.

Clinical recognition and differential diagnosis

Pilomatricoma is a usually benign hair-matrix tumour. Its defining histology combines basaloid matrical cells with anucleate ghost or shadow cells, often accompanied by calcification, foreign-body giant-cell reaction and occasionally bone formation. A firm head-and-neck nodule is characteristic.
Peutz–Jeghers syndrome is an autosomal dominant STK11-associated hamartomatous polyposis syndrome with characteristic mucocutaneous pigmentation. Its polyps contain branching smooth-muscle bundles extending through the lamina propria.
Chronic irritation, infection and prolonged catheterisation are associated with squamous metaplasia and increased risk of bladder squamous cell carcinoma, though urothelial carcinoma remains common overall.

Investigations and diagnostic interpretation

Chronic ultraviolet exposure predisposes to keratinocyte malignancy. An indurated persistent lower-lip ulcer is suspicious for squamous cell carcinoma and requires urgent assessment and biopsy, with regional-node evaluation.
Reassess with targeted imaging and repeat ultrasound-guided aspiration or obtain core/open histology after specialist discussion.
Assess the primary lesion and nodal basin; ultrasound helps characterise suspicious accessible nodes.
Unusual or enlarging lesions may need biopsy to exclude infection or malignancy.

Management and operative principles

Rapid growth, fixation, ulceration or atypical features warrant further assessment.
Surgical excision is common curative treatment.

Measurements, staging and thresholds

Persistent indurated oral ulcers, especially on the lateral tongue and in patients exposed to tobacco or alcohol, must be evaluated for squamous cell carcinoma. Tissue biopsy confirms the diagnosis and staging includes assessment of regional cervical nodes.
Regional nodal metastasis alters staging and should prompt specialist multidisciplinary planning.
An unexplained oral ulcer lasting more than three weeks warrants urgent assessment.

Common examiner traps

Do not confuse diagnostic sampling of a clinically abnormal node with sentinel lymph-node mapping of a clinically node-negative basin.
Do not confuse the commonest overall bladder histology (urothelial) with the type linked to chronic irritation (squamous).
Do not infer BCC solely from a poorly transcribed word such as “basaloid” when the biopsy shows squamous differentiation.
A radiolucent foreign body may be missed on X-ray; ultrasound and clinical history matter.
A previous colorectal cancer does not prove that a new scalp ulcer is metastatic disease.

Rapid-recall exam pearls

A large suspicious skin ulcer needs an adequate diagnostic tissue biopsy before definitive treatment planning.
Biopsy-proven cutaneous SCC + new firm regional node = ultrasound-guided nodal tissue assessment.
A fast-growing keratin-crater nodule suggests keratoacanthoma—but exclude SCC histologically.
Keratin pearls = squamous differentiation; palisading basaloid nests = basal-cell carcinoma.
Long-term bladder irritation or catheter use raises the possibility of squamous carcinoma.

Vascular

Aneurysms and aortic pathology

Overview. Aortic aneurysm and dissection are distinct vascular diseases: aneurysm concerns progressive dilatation, whereas dissection creates a false lumen and may impair perfusion.

Topic map — key distinctions

Subtopic	Defining feature / key principle
AAA diagnosis and surveillance	An asymptomatic 4.7-cm AAA in a man without rapid growth is below the usual elective repair threshold of 5.5 cm.
Rupture and emergency management	A 5.5-cm iliac aneurysm ordinarily merits vascular evaluation because rupture risk may be significant, but intervention should be weighed against life expectancy, symptoms, procedural risk, anatomy and the…
Aortic dissection	An uncomplicated acute Stanford type B dissection is initially managed medically with close monitoring, pain control and anti-impulse therapy.
EVAR versus open repair	An uncomplicated acute Stanford type B dissection is initially managed medically with close monitoring, pain control and anti-impulse therapy.

1. AAA diagnosis and surveillance

An asymptomatic 4.7-cm AAA in a man without rapid growth is below the usual elective repair threshold of 5.5 cm. Serial ultrasound surveillance, vascular referral and modification of smoking, blood pressure and other cardiovascular risks are appropriate. Surveillance intervals vary by national programme; NICE uses the NHS AAA screening programme frequency.

In the UK NHS screening surveillance pathway, an asymptomatic 4.5–5.4-cm AAA is monitored by ultrasound every three months, alongside vascular assessment and cardiovascular risk reduction. Elective repair in a man is usually considered at 5.5 cm or with rapid growth or symptoms; thresholds and intervals differ between international guidelines.
A new painful AAA is potentially unstable even if blood pressure is preserved. In a stable patient, urgent CTA defines aneurysm anatomy, leak/rupture and endovascular feasibility while vascular specialists prepare definitive management. An unstable patient must not have lifesaving intervention delayed for CT.
Aneurysm neck and iliac anatomy, patient fitness, life expectancy, durability, surveillance burden and patient preference.
AAA enlargement reflects weakening of the full arterial wall, unlike a pseudoaneurysm.
For most asymptomatic men with a 4.7-cm infrarenal AAA, surveillance is preferred over prophylactic repair. The typical elective repair threshold in men is about 5.5 cm, modified by symptoms, growth and anatomy.
Stable 1.3-cm femoral pseudoaneurysm with no complications: duplex surveillance is an option.

2. Rupture and emergency management

A 5.5-cm iliac aneurysm ordinarily merits vascular evaluation because rupture risk may be significant, but intervention should be weighed against life expectancy, symptoms, procedural risk, anatomy and the patient’s priorities. With terminal malignancy and a strong preference to avoid burdensome care, a documented shared decision may favour symptom-focused management after specialist assessment.

Ruptured AAA is a life-threatening haemorrhagic emergency. Call the vascular team, resuscitate judiciously, and rapidly evaluate for endovascular or open repair according to stability, anatomy and local capability. Imaging must not create avoidable delay in a collapsing patient.
The combination strongly suggests ruptured AAA with haemodynamic instability. In a patient too unstable for CT, rapid transfer to a vascular-capable operating theatre or hybrid suite for definitive haemorrhage control is appropriate, with resuscitation in parallel.
Haemodynamic instability or suspected rupture demands immediate resuscitation and vascular intervention without delaying for nonessential imaging.
Rupture, malperfusion, extension, uncontrolled hypertension or intractable pain change the plan toward intervention.
NICE supports immediate bedside ultrasound and urgent vascular discussion for suspected symptomatic/ruptured AAA.
Haemodynamically stable suspected rupture generally undergoes urgent CT angiography for EVAR planning.

3. Aortic dissection

An uncomplicated acute Stanford type B dissection is initially managed medically with close monitoring, pain control and anti-impulse therapy. Intravenous beta blockade reduces heart rate and aortic shear stress; additional vasodilators may be added after rate control if required. Complications such as rupture, malperfusion or persistent uncontrolled pain or pressure warrant urgent intervention, usually TEVAR when suitable.

Any dissection involving the ascending aorta is Stanford type A, regardless of the site of the entry tear. It is a surgical emergency because of rupture, tamponade, coronary malperfusion and aortic regurgitation risks; anti-impulse therapy is initiated while surgery is organised.
The coronary ostia arise from the aortic sinuses within the root, proximal to the arch vessels. A type A dissection can obstruct a coronary ostium, often the right, causing acute myocardial ischaemia and sometimes inferior ST elevation.
Type A dissection requires emergency specialist surgery in most patients.
Type A dissection requires emergency cardiac surgical assessment.
Type A dissection requires emergency cardiothoracic assessment.
Stanford type A requires emergency cardiac surgical management.

4. EVAR versus open repair

EVAR versus open repair depends on anatomy, availability and physiological status.
EVAR or open repair is selected by anatomy, local expertise and patient factors.
Do not equate elective repair indication with mandatory open surgery; EVAR and open repair have different trade-offs.
Haemodynamically stable suspected rupture generally undergoes urgent CT angiography for EVAR planning.
Complicated type B dissection may require thoracic endovascular aortic repair (TEVAR).
EVAR eligibility depends on neck, access vessels and device instructions for use.

Applied anatomy and pathology

Classic Marfan syndrome is an autosomal-dominant connective-tissue disorder caused by pathogenic variants in FBN1, encoding fibrillin-1, a microfibrillar protein essential for elastic-fibre architecture and regulation of TGF-beta signalling. Aortic-root dilatation and dissection are major complications.
The external iliac artery passes deep to the inguinal ligament at the mid-inguinal point and continues as the common femoral artery in the femoral triangle. The common femoral artery subsequently divides into superficial femoral and profunda femoris branches, with anatomical variation in branch level.
Type A involves the ascending aorta; type B is confined distal to the left subclavian origin.

Clinical recognition and differential diagnosis

Chronic hypertension and inherited connective-tissue aortopathies strongly predispose to aortic dissection. Diabetes mellitus has not been established as a major dissection risk factor and is sometimes inversely associated in epidemiological studies.
Most sporadic infrarenal abdominal aortic aneurysms arise through multifactorial degenerative wall remodelling associated strongly with smoking, age, male sex and atherosclerotic risk factors. Elastin/collagen loss and chronic inflammation weaken the wall.
Degenerative abdominal aortic aneurysm involves proteolysis of elastin and collagen, inflammatory-cell infiltration, smooth-muscle-cell loss and progressive wall weakening. Matrix metalloproteinases, including MMP-2 and MMP-9, participate in extracellular-matrix degradation.

Investigations and diagnostic interpretation

For an appropriately selected symptomatic iatrogenic femoral pseudoaneurysm, ultrasound-guided thrombin injection can thrombose the sac while preserving flow in the parent artery. Management depends on size, neck anatomy, anticoagulation, infection and haemodynamic stability.
Aortic dissection begins with blood entering the media, often through an intimal tear, and propagating along weakened medial planes. Medial degeneration with fragmentation of elastic fibres and loss of smooth-muscle integrity predisposes to dissection, particularly with hypertension or connective-tissue disorders.
Thrombotic occlusion within a demonstrated popliteal artery aneurysm can abruptly reduce distal perfusion and cause thromboembolism into tibial vessels. Bilateral popliteal aneurysms are common enough to justify contralateral screening. The diagnostic duplex makes the mechanism explicit, unlike the original recall.
A new symptomatic aneurysm requires urgent specialist assessment and repair planning. In a stable patient, CT angiography rapidly delineates aneurysm morphology, neck, iliac access and signs of rupture, informing endovascular versus open strategy.

Management and operative principles

Management includes optimisation, decompressive measures and urgent surgical decompression for refractory overt ACS.
Acute limb ischaemia requires urgent vascular assessment and systemic anticoagulation unless contraindicated.
Management requires urgent vascular evaluation and is tailored to infection, perfusion and anatomy.
Treat the cause of AKI and consider renal replacement therapy if hyperkalaemia is refractory.

Measurements, staging and thresholds

A 6.1-cm infrarenal AAA exceeds the commonly used 5.5-cm threshold at which elective repair should be considered in men. Referral for shared decision-making and CT angiographic planning is appropriate. Endovascular versus open repair depends on aortic anatomy, operative fitness, life expectancy and patient preference.
Symptoms, rapid growth (for example >1 cm/year), or reaching the usual male repair threshold of 5.5 cm; individualise for anatomy and fitness.
In men, elective AAA repair is commonly considered at diameter 5.5 cm or greater; lower thresholds may apply in women.
Initial targets commonly include HR about 60–80/min and systolic BP below 120 mmHg if organ perfusion permits.

Common examiner traps

K 5.6 mmol/L without ECG changes does not automatically mandate IV calcium; the reconstruction deliberately adds severe K and ECG changes.
Do not confuse the mid-inguinal point (arterial pulse) with the midpoint of the inguinal ligament (between ASIS and pubic tubercle).
Do not label every dissection-related pulse deficit a thromboembolus; dynamic true-lumen compression is an important alternative.
Diabetes is a major atherosclerotic risk factor, but do not automatically transfer that association to aortic dissection.
Do not equate elective repair indication with mandatory open surgery; EVAR and open repair have different trade-offs.

Rapid-recall exam pearls

After major aortic surgery, bladder pressure 26 mmHg plus oliguria and ventilatory deterioration is abdominal compartment syndrome.
Uncomplicated Stanford B: medical anti-impulse treatment first; complicated Stanford B: urgent aortic-team intervention.
Stable symptomatic AAA: urgent CTA and vascular repair planning; unstable suspected rupture: do not delay intervention.
Acute limb ischaemia with a thrombosed popliteal aneurysm on imaging: identify the aneurysm as the culprit lesion.
Hyperkalaemia with ECG changes: calcium first to stabilise the myocardium, then lower and remove potassium.

Arterial, venous and vascular anatomy

Overview. Clinical vascular localisation depends on arterial branching, pulse examination, venous drainage and the anatomical relationship of vessels to surrounding structures.

Topic map — key distinctions

Subtopic	Defining feature / key principle
Arterial anatomy	Leriche syndrome is chronic aortoiliac occlusive disease.
Venous anatomy	Paget–Schroetter syndrome is effort-induced axillosubclavian vein thrombosis, often associated with venous thoracic outlet compression during repetitive arm movements.
Vascular imaging	CTA provides cross-sectional angiographic assessment of the carotid lumen and distal patency, helping distinguish near-occlusion from complete occlusion when duplex is inconclusive.

1. Arterial anatomy

Leriche syndrome is chronic aortoiliac occlusive disease. The combination of buttock or thigh claudication, erectile dysfunction and weak or absent femoral pulses localises disease proximal to the femoral arteries.

The common carotid artery usually bifurcates at approximately the C4 vertebral level, near the superior border of the thyroid cartilage. There is anatomical variation; the bifurcation may be higher or lower in individual patients.
The common carotid artery usually divides into internal and external carotid arteries near the superior border of the thyroid cartilage, approximately C4.
The carotid sinus is near the proximal internal carotid artery.
The main intercostal neurovascular bundle lies in the costal groove along the inferior border of the rib, usually ordered vein, artery, nerve from superior to inferior. Entering just above the superior border of the rib below reduces the risk of injuring this bundle, although collateral vessels and anatomical variants mean the technique is not risk-free.
A cervical rib can narrow the thoracic outlet and compress the subclavian artery, especially with arm elevation. Dynamic arterial compression on provocative duplex together with a cervical rib supports arterial thoracic outlet syndrome. Persistent antegrade vertebral flow argues against a classic subclavian steal mechanism.
A partial arterial-wall injury can form a false aneurysm enclosed by surrounding tissue. A pulsatile mass with colour-flow communication to an artery and a to-and-fro Doppler waveform at the neck is characteristic. In a finger, careful vascular and hand-surgical evaluation is needed because distal perfusion and neurovascular anatomy govern treatment.

2. Venous anatomy

Paget–Schroetter syndrome is effort-induced axillosubclavian vein thrombosis, often associated with venous thoracic outlet compression during repetitive arm movements. Mechanical compression and intimal injury predispose to thrombosis.

The main intercostal neurovascular bundle lies in the costal groove along the inferior border of the rib, usually ordered vein, artery, nerve from superior to inferior. Entering just above the superior border of the rib below reduces the risk of injuring this bundle, although collateral vessels and anatomical variants mean the technique is not risk-free.
The saphenous nerve is the longest cutaneous branch of the femoral nerve and carries fibres predominantly from L3–L4. It accompanies the great saphenous vein in the leg and supplies the medial leg and medial foot.
The sural nerve is a purely sensory nerve running close to the small saphenous vein in the posterior calf and supplies the posterolateral leg and lateral foot.
Vein superior, artery middle, nerve inferior; place the instrument above the rib below.
Costal groove bundle: VAN (vein, artery, nerve) from superior to inferior.
The axillary/subclavian vein at the costoclavicular space.

3. Vascular imaging

CTA provides cross-sectional angiographic assessment of the carotid lumen and distal patency, helping distinguish near-occlusion from complete occlusion when duplex is inconclusive. This distinction affects eligibility for intervention and requires specialist stroke/vascular review.

Duplex ultrasound combines anatomical imaging and Doppler flow measurements without nephrotoxic contrast or radiation. It is an appropriate initial vascular imaging test when renal dysfunction makes contrast-enhanced CT or MR angiography less attractive.
Provocative duplex and CTA/MRA with positional manoeuvres help document vascular compression.
The duplex to-and-fro neck waveform is highly characteristic of a pseudoaneurysm.
CTA or contrast-enhanced MRA can confirm anatomy when duplex is uncertain.
Urgent venous duplex is useful but treatment should not be delayed.
Noncontrast MRA can be useful when duplex is limited.

Applied anatomy and pathology

Reactive oxygen species from smoking reduce nitric oxide bioavailability, including by reacting with NO to form peroxynitrite. Less NO reaches vascular smooth muscle, reducing soluble-guanylate-cyclase/cGMP-mediated relaxation. Smoking also promotes inflammation, thrombosis and accelerated atherosclerosis.
The recurrent laryngeal nerve, a branch of the vagus, supplies most intrinsic laryngeal muscles. Vagal or recurrent laryngeal injury during carotid dissection can cause ipsilateral vocal-fold paralysis and hoarseness.
Higher ankle systolic pressure (dorsalis pedis or posterior tibial) divided by the higher brachial systolic pressure.

Clinical recognition and differential diagnosis

A swollen blue leg with severe pain suggests phlegmasia cerulea dolens.
Cancer is an important hypercoagulable risk factor.

Investigations and diagnostic interpretation

Severe symptomatic hypokalaemia with ECG changes requires carefully controlled intravenous potassium replacement under monitoring; concomitant magnesium deficiency must be corrected because it promotes renal potassium loss and makes hypokalaemia refractory.
Imaging choice depends on renal function, urgency and whether revascularisation is planned.
Use thoracic ultrasound for pleural fluid procedures and appropriate imaging when required.
Assess pulmonary, cardiac and renal involvement where systemic sclerosis is suspected.

Management and operative principles

Phlegmasia cerulea dolens is extensive venous outflow obstruction causing painful cyanotic oedema and threatened venous perfusion. Prompt anticoagulation, resuscitation and urgent specialist assessment for endovascular or surgical thrombus removal are essential.
Treatment is individualised to symptoms, growth, collateral perfusion and hand-surgery assessment.
Time to intervention matters; ideally treat within two weeks when appropriate.
Medial-foot sensory loss after great-saphenous surgery suggests this nerve.

Measurements, staging and thresholds

Measure resting ankle–brachial index; further vascular imaging guides revascularisation.
Toe–brachial index and waveforms help when ankle arteries are noncompressible.
Ankle–brachial pressure index is a useful physiological screening test.
Use NASCET criteria when quoting carotid stenosis severity.

Common examiner traps

An apparent 99% lesion may represent near-occlusion, which is not managed identically; this reconstruction specifies 80% without near-occlusion.
Free radicals do not primarily act by binding a mythical “nitric oxide receptor”; they chemically inactivate NO and disrupt signalling.
An older recall lists catheter angiography; contemporary non-invasive CTA/MRA is commonly preferred for clarification.
Do not diagnose subclavian steal solely from dizziness or arm discomfort without the vertebral-flow mechanism.
Raynaud is a phenomenon, not a single diagnosis; do not dismiss digital ulcers or capillary dropout.

Rapid-recall exam pearls

Position-dependent arm ischaemia plus cervical rib and dynamic arterial compression indicates arterial TOS.
Pulsatile post-traumatic finger mass plus to-and-fro Doppler neck flow = digital artery pseudoaneurysm.
Smoking-derived oxidative stress scavenges nitric oxide and impairs endothelium-dependent relaxation.
Duplex cannot tell near-occlusion from occlusion: obtain CTA/MRA before deciding intervention.
Symptomatic 80% ICA stenosis in a fit patient: urgent ipsilateral CEA plus medical therapy.

Peripheral arterial disease and ischaemia

Overview. Peripheral arterial disease causes reduced exercise perfusion, whereas acute limb ischaemia may threaten viability within hours; symptom timing and motor deficit guide urgency.

Topic map — key distinctions

Subtopic	Defining feature / key principle
Chronic claudication	A normal resting ABI does not exclude exertional PAD, particularly in early or proximal disease.
Acute limb ischaemia	Atrial fibrillation predisposes to left atrial thrombus formation and systemic arterial embolisation.
Aortoiliac disease	Leriche syndrome results from chronic occlusive disease of the infrarenal aorta and/or iliac arteries, reducing pelvic and lower-extremity arterial inflow.
Mesenteric and visceral ischaemia	Cardiac emboli associated with atrial fibrillation commonly lodge in the superior mesenteric artery.
Revascularisation strategy	Focal short stenoses are often suitable for angioplasty.

1. Chronic claudication

A normal resting ABI does not exclude exertional PAD, particularly in early or proximal disease. If symptoms are typical of arterial claudication and resting ABI is normal or borderline, an exercise ABI can reveal a significant post-exercise ankle pressure reduction. Duplex ultrasound can subsequently help localise arterial disease if intervention is contemplated.

Typical claudication with normal resting ABI → consider exercise ABI.
Pentoxifylline has been used as a haemorrheological symptomatic agent for claudication, although evidence of clinically important benefit is limited and it is not recommended as an effective cardiovascular event-prevention drug. Statins, antiplatelet agents and risk-factor treatment address systemic atherothrombotic risk.
Proximal aortoiliac obstruction can produce buttock, hip and thigh claudication with reduced femoral pulses. Femoropopliteal disease more typically causes calf claudication, while isolated distal tibial disease usually affects foot perfusion. Imaging is included to resolve the original source ambiguity, which described thigh pain alone.
For persistent lifestyle-limiting claudication despite conservative management, a short anatomically suitable femoropopliteal lesion is often treated by endovascular angioplasty. Surgical bypass is considered if angioplasty is unsuitable or fails.
Buttock and proximal-thigh claudication with a reduced femoral pulse localises arterial disease to the aortoiliac inflow system. A unilateral common iliac stenosis can reduce inflow to the whole limb and cause proximal exertional symptoms.
Severe lifestyle-limiting claudication with unsuitable or unsuccessful endovascular therapy and suitable conduit/target.

2. Acute limb ischaemia

Atrial fibrillation predisposes to left atrial thrombus formation and systemic arterial embolisation. An embolus can acutely occlude a previously normal limb artery, causing abrupt pain, pallor, pulselessness and other features of acute limb ischaemia. This is a vascular emergency.

Acute limb ischaemia with new motor deficit is an immediately threatened limb (Rutherford IIb) requiring urgent revascularisation. An embolus from atrial fibrillation may be treated with urgent embolectomy; anticoagulation is started promptly if not contraindicated.
Immediate heparin is standard for acute limb ischaemia unless contraindicated, alongside vascular review.
A duration of more than two weeks helps distinguish chronic rest pain from acute limb ischaemia.
Acute limb ischaemia with motor deficit requires emergency revascularisation.
Sudden ischaemia in atrial fibrillation, a previously asymptomatic limb and an abrupt arterial cut-off with scant collaterals strongly suggest embolic acute limb ischaemia. Urgent vascular assessment and systemic anticoagulation when not contraindicated are required.

3. Aortoiliac disease

Leriche syndrome results from chronic occlusive disease of the infrarenal aorta and/or iliac arteries, reducing pelvic and lower-extremity arterial inflow. The classic clinical triad is buttock/thigh claudication, erectile dysfunction and reduced or absent femoral pulses.

Buttock claudication plus impotence plus weak femoral pulses = Leriche syndrome.

4. Mesenteric and visceral ischaemia

Cardiac emboli associated with atrial fibrillation commonly lodge in the superior mesenteric artery. Early acute mesenteric ischaemia may produce intense visceral pain before peritoneal signs develop. Immediate CT angiography and urgent multidisciplinary vascular/surgical care are required.

Abrupt severe pain in a patient with atrial fibrillation and a discrete SMA filling defect suggests cardioembolic acute mesenteric ischaemia. CT angiography should be obtained urgently; resuscitation, antibiotics, anticoagulation when appropriate and rapid vascular/surgical assessment are essential.
CT angiography should be obtained without delay when acute mesenteric ischaemia is suspected.
A normal early lactate does not exclude mesenteric ischaemia.
Urgent CT angiography of the mesenteric vessels.
Normal early lactate or minimal tenderness does not exclude mesenteric ischaemia.

5. Revascularisation strategy

Focal short stenoses are often suitable for angioplasty.
For persistent lifestyle-limiting claudication despite conservative management, a short anatomically suitable femoropopliteal lesion is often treated by endovascular angioplasty. Surgical bypass is considered if angioplasty is unsuitable or fails.
Claudication refractory to exercise plus short suitable stenosis: consider angioplasty.
Do not offer angioplasty as the automatic first step for all patients with mild intermittent claudication.

Applied anatomy and pathology

The superficial femoral artery traverses the adductor canal to become the popliteal artery. A haemodynamically important lesion can preserve a proximal femoral pulse while reducing popliteal and pedal pulses and causing exercise-induced calf-muscle ischaemia.
Medial arterial calcification makes vessels incompressible; toe pressure and waveform assessment are often more informative.
Ischaemic muscle releases intracellular potassium, potentially causing malignant arrhythmias.

Clinical recognition and differential diagnosis

Pain reproduced by restricted hip rotation points to an intrinsic hip-joint disorder, particularly osteoarthritis, rather than isolated vascular or neurogenic claudication.
Neuropathic ulcers occur at pressure points with sensory loss and callus; arterial ulcers often occur distally with pain, cool skin and reduced pulses.
CLTI encompasses ischaemic rest pain, nonhealing ischaemic ulceration or gangrene attributable to PAD.

Investigations and diagnostic interpretation

A femoro-femoral crossover graft transfers blood from a well-perfused contralateral common femoral artery to the ischaemic side, avoiding repeat major aortic surgery in a high-risk patient. Adequate donor-side inflow is essential.
Assess the six Ps: pain, pallor, pulselessness, paraesthesia, paralysis and poikilothermia.
Statins and antiplatelet therapy, alongside management of blood pressure and diabetes.
Duplex ultrasound is first-line vascular imaging when revascularisation is considered.

Management and operative principles

Giant cell arteritis is a granulomatous vasculitis of large- and medium-sized arteries that can cause irreversible ischaemic visual loss. Suspected cranial GCA with visual symptoms warrants immediate high-dose glucocorticoid treatment and urgent specialist evaluation.
Give immediate systemic anticoagulation with intravenous unfractionated heparin when not contraindicated and obtain urgent vascular assessment.
Pain out of proportion and tense compartments warrant urgent compartment-pressure assessment and fasciotomy when indicated.
Peritonitis suggests bowel infarction and usually requires urgent operative exploration.

Measurements, staging and thresholds

An immediately threatened limb with more than minimal sensory loss and mild-to-moderate weakness requiring urgent revascularisation.
Measure ankle–brachial pressure index (ABPI) and use toe pressures if arteries are incompressible, especially in diabetes.
Ankle-brachial index, toe pressures or toe-brachial index, duplex and anatomical imaging when planning revascularisation.
IIb has more than minimal sensory loss and mild/moderate weakness; IIa is marginally threatened without motor deficit.

Common examiner traps

Three patent tibial runoff vessels do not by themselves indicate a popliteal-tibial bypass; first identify the level of occlusion.
Do not assume bypass is always superior: lower-complexity lesions and high-risk patients may favour endovascular treatment.
Do not call this haematuria solely because the urine dipstick reads blood; microscopy and CK distinguish myoglobinuria.
Do not use a non-removable cast indiscriminately in severe infection or significant ischaemia; reassess the limb first.
Smoking plus any ulcer does not establish Buerger disease; vascular distribution and exclusion of mimics matter.

Rapid-recall exam pearls

Treat neuropathic plantar diabetic foot ulcers with effective offloading, not antibiotics in the absence of infection.
Unilateral iliac occlusion plus a healthy contralateral inflow can be treated by femoro-femoral crossover.
Long complex femoropopliteal occlusion + good distal target + usable vein may favour distal vein bypass.
Night forefoot pain relieved by dependency plus objectively severe PAD = CLTI, not simple claudication.
Young heavy smoker + distal digital ischaemia + migratory thrombophlebitis = consider Buerger disease.

Vascular anatomy and intervention

Overview. Endovascular and open vascular techniques are selected by lesion anatomy, operative risk and whether urgent revascularisation is required.

Topic map — key distinctions

Subtopic	Defining feature / key principle
Anatomical landmarks	An axillobifemoral graft provides extra-anatomic inflow from an axillary artery to both femoral arteries, avoiding laparotomy and aortic clamping in selected high-risk patients with severe aortoiliac disease.
Imaging for intervention	Duplex surveillance can detect graft stenosis before occlusion.

1. Anatomical landmarks

An axillobifemoral graft provides extra-anatomic inflow from an axillary artery to both femoral arteries, avoiding laparotomy and aortic clamping in selected high-risk patients with severe aortoiliac disease.

Unfit for aortic surgery + bilateral iliac occlusion = consider axillobifemoral bypass.
Aortobifemoral bypass may be more durable but is not automatically safest.

2. Imaging for intervention

Duplex surveillance can detect graft stenosis before occlusion.

Applied anatomy and pathology

Vein grafts undergo arterialisation and endothelial injury. Smooth-muscle-cell migration and extracellular-matrix deposition thicken the intima, producing neointimal hyperplasia, especially during the first 1–2 postoperative years; late atherosclerosis is a separate mechanism.
Superior hypogastric plexus lies anterior to the lower aorta and sacral promontory.
Cardiac muscle contracts without a skeletal-type neuromuscular junction.

Investigations and diagnostic interpretation

An aggressive bone lesion in a young person requires urgent specialist sarcoma referral. MRI maps intramedullary and soft-tissue extent and informs biopsy planning; an unplanned biopsy tract can compromise later limb-sparing surgery.
Mechanical compression may be inappropriate in severe arterial insufficiency; assess limb perfusion.
MRI should cover the whole involved bone, relevant compartment and adjacent joints.
Two-plane radiographs are the first imaging investigation.

Management and operative principles

NICE NG89: consider LMWH for at least seven days after open vascular surgery when VTE risk exceeds bleeding risk.
Retrograde ejaculation differs from erectile dysfunction and can occur after aortoiliac surgery.
Acute graft occlusion with threatened limb requires urgent vascular assessment.
The tract may require en-bloc removal with the tumour at definitive surgery.

Measurements, staging and thresholds

Staging usually includes chest CT once malignancy is suspected or confirmed.

Common examiner traps

A mixed lytic-sclerotic lesion does not itself prove osteosarcoma; preserve differential diagnosis until histology.
Do not prescribe lifelong warfarin or routine IVC filters as postoperative prophylaxis.
Aortobifemoral bypass may be more durable but is not automatically safest.
Desmosomes provide mechanical adhesion; gap junctions conduct excitation.

Rapid-recall exam pearls

Preserved erections with absent antegrade semen after aortoiliac surgery suggests sympathetic hypogastric injury and retrograde ejaculation.
Unfit for aortic surgery + bilateral iliac occlusion = consider axillobifemoral bypass.
Suspected primary bone sarcoma: refer before biopsy and obtain specialist-directed MRI.
PAD does not protect against DVT; use individual VTE and bleeding-risk assessment.
Vein bypass + stenosis around 6–24 months = intimal hyperplasia.

Vasculitis and Raynaud disease

Overview. Differentiate inflammatory vessel disease from episodic vasospasm; systemic findings and ischaemic complications direct investigation.

Topic map — key distinctions

Subtopic	Defining feature / key principle
Primary versus secondary Raynaud	Raynaud phenomenon is episodic digital vasospasm.

1. Primary versus secondary Raynaud

Raynaud phenomenon is episodic digital vasospasm. It may be primary or secondary to connective tissue disease, including systemic sclerosis, SLE and rheumatoid arthritis. Evaluate for red flags such as ulcers, asymmetric attacks and abnormal nailfold capillaries.

Primary Raynaud phenomenon causes episodic reversible digital vasospasm. After avoiding cold and other triggers, a dihydropyridine calcium-channel blocker such as nifedipine is a common first-line medication for troublesome attacks. Normal capillaroscopy and absence of connective-tissue disease features support primary rather than secondary Raynaud phenomenon.
Primary Raynaud often begins at a younger age and has symmetric attacks.
Raynaud is triggered by cold or emotional stress.
Troublesome primary Raynaud: try nifedipine after trigger avoidance.
Connective tissue diseases can cause secondary Raynaud phenomenon.

Common examiner traps

Digital ulcers, asymmetric attacks or abnormal capillaroscopy suggest secondary disease and require further evaluation.
Do not label asymmetric, ulcerating or late-onset Raynaud as benign primary disease without assessment.

Rapid-recall exam pearls

Troublesome primary Raynaud: try nifedipine after trigger avoidance.
Connective tissue diseases can cause secondary Raynaud phenomenon.

Venous disease and thrombosis

Overview. Venous disorders present with swelling, varicosities, ulceration or thromboembolism; duplex ultrasound defines important venous anatomy and flow.

Topic map — key distinctions

Subtopic	Defining feature / key principle
DVT and pulmonary embolism	Post-thrombotic syndrome results from residual venous obstruction and valvular reflux after DVT.
Varicose veins and reflux	Chronic venous hypertension produces oedema, hemosiderin pigmentation and inflammatory dermatitis in the gaiter area.
Chronic venous disease	A classic venous ulcer with adequate arterial perfusion is managed with evidence-based compression, which reduces ambulatory venous hypertension and oedema and promotes healing.

1. DVT and pulmonary embolism

Post-thrombotic syndrome results from residual venous obstruction and valvular reflux after DVT. Graduated compression can reduce swelling and discomfort; exercise, weight management and skin care are important. Anticoagulation duration depends on recurrent VTE risk, not PTS symptoms alone.

Compression is for symptom relief; evidence for universal prevention after every DVT is mixed.

2. Varicose veins and reflux

Chronic venous hypertension produces oedema, hemosiderin pigmentation and inflammatory dermatitis in the gaiter area. Varicose eczema is an indication for venous assessment and management of reflux.

Itchy pigmented eczema around the ankle in varicose disease is venous eczema.

3. Chronic venous disease

A classic venous ulcer with adequate arterial perfusion is managed with evidence-based compression, which reduces ambulatory venous hypertension and oedema and promotes healing. Compression must be selected after vascular assessment; severe arterial insufficiency is a contraindication to standard high compression. Treat venous reflux where indicated to reduce recurrence.

Established PTS is treated symptomatically with compression, exercise and venous-ulcer care.
Venous ulcer + adequate ABI → compression is core treatment.
Do not apply strong compression to an ischaemic limb solely because the ulcer is medial.
Symptoms include heaviness, oedema, pigmentation, eczema and sometimes ulceration.
Venous ulcers usually occur in the gaiter region with haemosiderin pigmentation.
Atypical or non-healing ulcers may require biopsy to exclude malignancy.

Applied anatomy and pathology

Intrathecal local anaesthetic blocks spinal nerve conduction, including sympathetic preganglionic fibres. Arteriolar and venous dilatation reduce systemic vascular resistance and venous return; high blocks may also cause bradycardia. Management includes positioning, appropriate fluid assessment and vasopressors.
Failure of superficial/deep venous valves or venous outflow obstruction produces sustained ambulatory venous hypertension, leading to gaiter pigmentation, eczema, lipodermatosclerosis and a typically shallow medial ankle ulcer.
The hypoglossal nerve provides motor innervation to the tongue; a unilateral lower motor neurone lesion causes tongue deviation toward the weak side on protrusion. It is at risk during carotid exposure and retraction.

Clinical recognition and differential diagnosis

The common fibular nerve winds superficially around the fibular neck and divides into deep and superficial branches. A lesion proximal to that division weakens dorsiflexion (deep branch) and eversion (superficial branch), with dorsal-foot sensory loss.
The saphenous nerve is a sensory terminal branch of the femoral nerve accompanying the long saphenous vein in the medial leg and ankle region. Injury produces medial leg or foot sensory deficit without motor weakness.
A single wedge-pressure value alone cannot definitively distinguish mixed ARDS and cardiogenic oedema.

Investigations and diagnostic interpretation

Classical lines of Zahn reflect lamination of platelets/fibrin and red-cell-rich components during flowing blood and support antemortem thrombosis. Contemporary histopathology emphasises that convincing thick platelet-fibrin bands are more specific than fine nonspecific fibrin strands.
Assess haemodynamic stability, bleeding risk and renal function before selecting therapy.
Assess arterial perfusion before strong compression when arterial disease is suspected.
Assess superficial/deep reflux and treat suitable venous disease.

Management and operative principles

Major lower-limb surgery and postoperative immobility increase VTE risk. When bleeding risk permits, prophylactic-dose LMWH is a commonly appropriate pharmacological option, with mechanical measures adapted to anatomy and local protocols.
Active bleeding, renal function, body weight, thrombocytopenia, prior VTE and local surgical protocol.
Acute variceal bleeding requires resuscitation, vasoactive therapy, antibiotics and urgent endoscopy.
Common fibular palsy can follow compression at the fibular head, knee trauma or surgery.

Measurements, staging and thresholds

Raised left atrial/pulmonary venous pressure drives fluid into pulmonary interstitium and alveoli. A wedge pressure of 20 mmHg with LV dysfunction and fluid overload supports cardiogenic pulmonary oedema.
ARDS is defined by respiratory criteria and opacities not fully explained by cardiac failure/fluid overload.
The Villalta score incorporates leg symptoms and signs, including oedema, pain and skin change.
Use toe pressure or toe–brachial index and vascular assessment.

Common examiner traps

LMWH was the original recall-era answer; modern eligible patients may start apixaban or rivaroxaban directly.
Thin fibrin strands alone are not fully specific; thick platelet-fibrin bands are more persuasive.
Do not prescribe lifelong anticoagulation solely because post-thrombotic swelling persists.
Do not assume every postoperative dysarthria is a peripheral nerve injury; exclude stroke.
A port still requires sterile needle access and maintenance; it is not complication-free.

Rapid-recall exam pearls

Elevated wedge pressure + LV dysfunction + diffuse oedema suggests hydrostatic pulmonary oedema.
After major amputation, prophylactic LMWH is appropriate when indicated and not contraindicated.
Established PTS is treated symptomatically with compression, exercise and venous-ulcer care.
Itchy pigmented eczema around the ankle in varicose disease is venous eczema.
Long-term intermittent IV therapy without an external line: implanted port.

FreeMedSite

MRCS Part A — Common Surgical Conditions — High Yield Notes

Acute Emergencies

Topic map — key distinctions

1. Necrotising infection

2. Occupational exposure

3. High spinal injuries

Clinical recognition and differential diagnosis

Management and operative principles

Common examiner traps

Rapid-recall exam pearls

Topic map — key distinctions

1. Recognition

Common examiner traps

Rapid-recall exam pearls

Topic map — key distinctions

1. Difficult intubation and oxygenation

2. Front-of-neck access

3. Neck landmarks and complications

Applied anatomy and pathology

Clinical recognition and differential diagnosis

Investigations and diagnostic interpretation

Measurements, staging and thresholds

Common examiner traps

Rapid-recall exam pearls

Topic map — key distinctions

1. Initial resuscitation

Applied anatomy and pathology

Clinical recognition and differential diagnosis

Investigations and diagnostic interpretation

Management and operative principles

Measurements, staging and thresholds

Common examiner traps

Rapid-recall exam pearls

Topic map — key distinctions

1. Bleeding and transfusion

Investigations and diagnostic interpretation

Management and operative principles

Common examiner traps

Rapid-recall exam pearls

Basic Sciences & Immunology

Topic map — key distinctions

1. Tissue pathology

2. Physiological response

Clinical recognition and differential diagnosis

Investigations and diagnostic interpretation

Common examiner traps

Rapid-recall exam pearls

Topic map — key distinctions

1. Cellular immunity

2. Antibodies and complement

3. Graft and transplant

Applied anatomy and pathology

Clinical recognition and differential diagnosis

Investigations and diagnostic interpretation

Management and operative principles

Measurements, staging and thresholds

Common examiner traps

Rapid-recall exam pearls

Topic map — key distinctions

1. Nociceptive signalling

Clinical recognition and differential diagnosis

Common examiner traps

Rapid-recall exam pearls

Breast

Topic map — key distinctions

1. Gynaecomastia mechanisms

2. Assessment

Investigations and diagnostic interpretation

Common examiner traps

Rapid-recall exam pearls

Topic map — key distinctions

1. Fibroadenoma and phyllodes

2. Cysts and fat necrosis

3. Mastitis and abscess

4. Risk and triple assessment

Applied anatomy and pathology

Clinical recognition and differential diagnosis

Investigations and diagnostic interpretation

Measurements, staging and thresholds