MRCS Part A — Common Surgical Conditions: Sections 10

MRCS Part A — Common Surgical Conditions: Sections 10–15

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MRCS Common Surgical Conditions — Sections 10–15

Enable JavaScript for the interactive quiz. The questions can also be read below. Recorded recall sessions are taken from the source document and have not been independently authenticated.

Question 1 (source Q596). An unvaccinated healthcare worker sustains a percutaneous injury from a source with high-level viraemia. Among the listed blood-borne viruses, which generally has the highest occupational transmission probability after a needlestick without prophylaxis?

Acute Emergencies — Acute surgical emergencies

Recorded recall sessions: April 2021

A. HIV

B. Hepatitis B virus

C. Hepatitis C virus

D. HTLV-1

Answer and explanation

B. Hepatitis B virus

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.

A. HIV has a lower average percutaneous transmission risk than HBV in a susceptible worker.

C. HCV can transmit through needlesticks but usually at lower probability than high-viraemia HBV.

D. HTLV-1 is not the classic highest-risk needlestick infection in this comparison.

HBV vaccination is essential for healthcare workers.
Immediate first aid, incident reporting and risk assessment are required.
HIV PEP should start promptly when indicated.
HBV prophylaxis depends on immunity and source status.

Exam pearl: Highest classic percutaneous infectivity in a susceptible worker: HBV.

Examiner trap: The ranking changes with vaccination, viral load and exposure type; never omit source and worker serology.

Viva extension: What immediate steps follow a needlestick? Wash, report, test source/worker and arrange urgent HIV/HBV/HCV exposure management.

Question 2 (source Q697). A man with diabetes develops rapidly progressive severe pain, tense swelling, skin discoloration and crepitus after a contaminated leg wound. He is hypotensive, and imaging shows gas within muscle. What is the single most urgent definitive intervention?

Acute Emergencies — Acute surgical emergencies

Recorded recall sessions: May 2024

A. Oral amoxicillin alone

B. Immediate radical surgical exploration and debridement

C. Elevation and ice

D. Delay surgery until cultures return

Answer and explanation

B. Immediate radical surgical exploration and debridement

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.

A. Oral monotherapy is inadequate for a fulminant necrotising infection.

C. Ice and elevation cannot remove necrotic tissue or stop toxin-mediated progression.

D. Culture confirmation must not delay life-saving surgery and empirical antimicrobials.

Clostridium perfringens is a classic cause of traumatic gas gangrene.
Pain out of proportion, rapid progression, crepitus and systemic toxicity are red flags.
Start intravenous antibiotics immediately, but antibiotics do not replace debridement.
Gas is not mandatory in every necrotising infection; clinical suspicion takes priority.

Exam pearl: Necrotising myonecrosis = urgent surgery plus immediate IV antimicrobials and resuscitation.

Examiner trap: Do not rely on CT or laboratory scoring to exclude necrotising infection when clinical suspicion is high.

Viva extension: What is the role of clindamycin? It may reduce toxin synthesis and is used with other appropriate agents in clostridial or streptococcal necrotising infections.

Question 3 (source Q975). A 29-year-old sustains a complete spinal cord injury at C6. He can generate spontaneous diaphragmatic breaths but has a weak cough and reduced chest-wall expansion. Which explanation is most accurate?

Acute Emergencies — Acute surgical emergencies

Recorded recall sessions: January 2021

A. The phrenic motor neurons arise chiefly from C3–C5 and are rostral to the C6 lesion.

B. The phrenic nerve arises entirely from C7–T1.

C. A C6 lesion invariably paralyses both hemidiaphragms.

D. Intercostal muscles are supplied by the vagus nerve.

Answer and explanation

A. The phrenic motor neurons arise chiefly from C3–C5 and are rostral to the C6 lesion.

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.

B. C7–T1 supplies other upper-limb structures; the diaphragm is primarily C3–C5.

C. High cervical lesions involving the C3–C5 motor outflow are far more likely to abolish diaphragmatic drive.

D. Intercostal muscles are innervated by thoracic spinal nerves, not the vagus.

C3, C4 and C5 keep the diaphragm alive.
Intercostal muscles receive segmental thoracic innervation.
Weak cough increases secretion retention and atelectasis risk.
Respiratory compromise also depends on completeness, level and associated trauma.

Exam pearl: C6 cord injury may spare the diaphragm but still severely weaken cough.

Examiner trap: Do not equate preserved spontaneous breathing with intact respiratory mechanics.

Viva extension: Why is a C2 complete lesion more dangerous? It disconnects the C3–C5 phrenic motor pool from descending respiratory drive, potentially necessitating ventilatory support.

Question 4 (source Q934). A 58-year-old man taking ramipril develops non-itchy tongue and lip swelling without urticaria. There is no clear allergen exposure, and airway assessment is underway. Which mediator most directly explains this drug-related angioedema?

Acute Emergencies — Anaphylaxis and airway emergencies

Recorded recall sessions: April 2026

A. IgE-mediated mast-cell histamine release

B. Prostaglandin E2

C. Interleukin-2

D. Bradykinin accumulation

Answer and explanation

D. Bradykinin accumulation

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.

A. Histamine-mediated allergic angioedema often accompanies urticaria, pruritus or anaphylaxis; the drug mechanism here is different.

B. PGE2 is not the primary mechanism of ACE-inhibitor angioedema.

C. IL-2 is not the direct mediator of ACE-inhibitor-related mucosal oedema.

ACE inhibitors reduce bradykinin degradation.
Absence of urticaria favours bradykinin-mediated angioedema, though it is not diagnostic alone.
Stop the causative ACE inhibitor permanently.
Tongue or laryngeal swelling requires urgent airway assessment.

Exam pearl: ACE inhibitor + nonpruritic tongue swelling = consider bradykinin angioedema.

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

Viva extension: Viva: What is the first priority? Repeated airway assessment, early senior anaesthetic/ENT involvement and airway control when indicated.

Question 5 (source Q70). In a cannot-intubate, cannot-oxygenate adult airway emergency, which anatomical membrane is opened for emergency front-of-neck access?

Acute Emergencies — Emergency airway management

Recorded recall sessions: April 2021

A. Cricothyroid membrane

B. Thyrohyoid membrane

C. Anterior tracheal wall at C7

D. Thyroid isthmus

Answer and explanation

A. 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.

B. Situated above the thyroid cartilage, not the standard emergency access site.

C. Too low and carries avoidable risk in an emergency.

D. A glandular structure that may obstruct a formal tracheostomy and is not the intended airway entry site.

The cricothyroid membrane is just inferior to thyroid cartilage
Emergency front-of-neck access requires trained technique and clear failed-airway indication
Paediatric airway strategies differ by age and local algorithm.

Exam pearl: Adult CICO emergency: cricothyroid membrane.

Examiner trap: A tracheostomy and a cricothyrotomy are anatomically different procedures.

Viva extension: What lies immediately inferior to the cricothyroid membrane? The cricoid cartilage.

Question 6 (source Q71). During a standard surgical tracheostomy, which structure typically crosses the anterior second to fourth tracheal rings?

Acute Emergencies — Emergency airway management

Recorded recall sessions: January 2020

A. Thyroid isthmus

B. Epiglottis

C. Carotid bifurcation

D. Thyrohyoid membrane

Answer and explanation

A. Thyroid isthmus

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.

B. Lies in the supraglottis, not in front of lower cervical tracheal rings.

C. Lies lateral to the upper cervical airway rather than across its anterior midline.

D. Connects hyoid and thyroid cartilage above the trachea.

Inferior thyroid veins may bleed during dissection
Locate tracheal rings carefully to avoid high or low tracheostomy
Never assume thyroid isthmus position is identical in all patients.

Exam pearl: Thyroid isthmus overlies the upper trachea.

Examiner trap: The tracheostomy opening must not be confused with the cricothyroid membrane.

Viva extension: Which vessel is a danger during a very low tracheostomy? An aberrant high brachiocephalic artery.

Question 7 (source Q137). A 34-year-old trauma patient cannot be intubated or oxygenated despite appropriate rescue attempts. Which anterior neck structure is opened for an emergency scalpel cricothyrotomy?

Acute Emergencies — Emergency airway management

Recorded recall sessions: January 2017; April 2021; May 2022

A. Thyrohyoid membrane

B. Second tracheal ring

C. Cricothyroid membrane

D. Thyroid isthmus

Answer and explanation

C. Cricothyroid membrane

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.

A. The thyrohyoid membrane lies between the hyoid bone and thyroid cartilage, above the intended cricothyrotomy site.

B. Opening a tracheal ring is part of tracheostomy rather than the usual emergency scalpel cricothyrotomy.

D. The thyroid isthmus overlies upper tracheal rings; dividing it is not the target of cricothyrotomy.

This is a rescue procedure for a cannot-intubate, cannot-oxygenate situation.
Identify the thyroid cartilage, cricoid cartilage and intervening membrane.
The membrane is superficial and usually avoids the thyroid isthmus.
A definitive airway and post-procedure airway assessment are still needed.

Exam pearl: CICO emergency → cricothyroid membrane.

Examiner trap: Do not confuse emergency cricothyrotomy with elective tracheostomy through tracheal rings.

Viva extension: Which cartilages border the membrane? Thyroid superiorly and cricoid inferiorly.

Question 8 (source Q341). An adult ICU patient undergoes a surgical tracheostomy through the second to fourth tracheal rings. Which midline structure commonly crosses this level and may need superior/inferior retraction or division?

Acute Emergencies — Emergency airway management

Recorded recall sessions: not recorded

A. Thymus

B. Cricoid cartilage

C. Thyroid isthmus

D. Epiglottis

Answer and explanation

C. Thyroid isthmus

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.

A. The thymus is predominantly in the anterior mediastinum and is not the usual midline structure over adult rings two to four.

B. The cricoid cartilage is immediately above the first tracheal ring, not across rings two to four.

D. The epiglottis is a supraglottic laryngeal structure, far superior to the tracheostomy level.

Thyroid isthmus typically overlies tracheal rings 2–4.
Open tracheostomy is distinct from emergency cricothyrotomy.
Identify and control anterior jugular and inferior thyroid veins.
Avoid injury to the cricoid and first ring when possible.

Exam pearl: In open tracheostomy, anticipate the thyroid isthmus at rings 2–4.

Examiner trap: Do not confuse tracheostomy with cricothyrotomy through the cricothyroid membrane.

Viva extension: Which membrane is used for emergency cricothyrotomy? The cricothyroid membrane between thyroid and cricoid cartilages.

Question 9 (source Q773). A 58-year-old ventilated patient is recovering from postoperative pneumonia. Sedation has been reduced; he is awake, haemodynamically stable, has adequate oxygenation on FiO2 0.35 and PEEP 5 cmH2O, and initiates breaths. Which next step best assesses readiness for liberation from invasive ventilation?

Acute Emergencies — Emergency airway management

Recorded recall sessions: April 2017

A. Progressively reduce the SIMV mandatory rate over several days

B. Perform a monitored spontaneous breathing trial using minimal or no inspiratory support

C. Insert a tracheostomy before testing spontaneous breathing

D. Extubate immediately without assessing airway protection

Answer and explanation

B. Perform a monitored spontaneous breathing trial using minimal or no inspiratory support

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.

A. Routine gradual SIMV-rate reduction can delay liberation compared with an SBT-based strategy.

C. Tracheostomy is not an automatic prerequisite when an appropriate patient can undergo an SBT.

D. SBT success and extubation readiness are related but distinct; airway protection must be considered.

An SBT typically lasts about 30–120 minutes and is closely monitored.
Assess improvement of the cause of respiratory failure, oxygenation, cardiovascular stability and spontaneous effort.
SBTs may be performed with or without low-level pressure support.
A successful SBT does not guarantee successful extubation if cough or secretion control is poor.

Exam pearl: Use a readiness screen followed by an SBT; do not reflexively wean SIMV rate for days.

Examiner trap: CPAP and pressure support are not interchangeable with full ventilator liberation, and passing an SBT alone does not establish airway safety.

Viva extension: What else is assessed before extubation? Cough strength, airway patency, secretion burden, mental status and risk of post-extubation failure.

Question 10 (source Q795). During an elective open tracheostomy, the surgeon divides skin and superficial tissues and opens the investing cervical fascia. Which next manoeuvre gives safe access towards the pretracheal fascia while limiting injury to lateral neck structures?

Acute Emergencies — Emergency airway management

Recorded recall sessions: January 2026

A. Divide both sternocleidomastoid muscles transversely

B. Separate the sternohyoid and sternothyroid strap muscles along the midline raphe

C. Enter the carotid sheath lateral to the trachea

D. Divide the cricothyroid membrane as the standard elective tracheostomy opening

Answer and explanation

B. Separate the sternohyoid and sternothyroid strap muscles along the midline raphe

After superficial dissection, the paired infrahyoid strap muscles are identified and separated in the relatively avascular midline. This exposes deeper pretracheal tissues and the thyroid isthmus/trachea while minimising unnecessary lateral dissection. A standard elective tracheostomy creates a tracheal opening below the cricoid rather than opening the cricothyroid membrane.

A. Sternocleidomastoid division is unnecessary and would endanger lateral neurovascular structures.

C. The carotid sheath contains the common carotid artery, internal jugular vein and vagus nerve; it is not the intended route.

D. Cricothyrotomy is a distinct emergency airway procedure and is not the usual elective tracheostomy opening.

The infrahyoid strap muscles include sternohyoid and sternothyroid, separated in the midline.
The thyroid isthmus may cross the anterior second to fourth tracheal rings.
A high-riding innominate artery and anterior jugular venous arch are important haemorrhage hazards.
Maintain strict midline orientation to avoid paratracheal vessels and nerves.

Exam pearl: In open tracheostomy, separate strap muscles in the midline rather than dissecting laterally.

Examiner trap: The fragmentary source “platysma cut → next layer → investing layer” omitted the operative question and did not specify the next safe plane.

Viva extension: Which glandular structure may require retraction or division before entering the trachea? The thyroid isthmus.

Question 11 (source Q971). A 34-year-old with severe maxillofacial trauma is profoundly hypoxaemic. Intubation has failed and neither optimised mask ventilation nor a supraglottic airway can provide oxygenation. An experienced airway team has declared a cannot-intubate-cannot-oxygenate emergency. Which front-of-neck procedure is the standard rapid rescue technique in adult difficult-airway algorithms?

Acute Emergencies — Emergency airway management

Recorded recall sessions: January 2024

A. Emergency scalpel-bougie cricothyrotomy

B. Wait for a formal elective open tracheostomy at the second tracheal ring

C. Continue repeated laryngoscopy indefinitely

D. Needle aspiration of the neck without establishing a ventilating airway

Answer and explanation

A. Emergency scalpel-bougie cricothyrotomy

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.

B. A formal tracheostomy generally takes longer and should not delay oxygenation in a critical CICO emergency.

C. Further futile attempts delay rescue oxygenation and increase airway trauma.

D. A needle puncture alone is not a definitive means of oxygenation and ventilation in this adult CICO scenario.

Declare CICO and call for help early.
Adult emergency FONA commonly uses scalpel-bougie cricothyrotomy.
The cricothyroid membrane lies between thyroid and cricoid cartilages.
A planned tracheostomy enters lower tracheal rings and is not the routine fastest CICO rescue.

Exam pearl: CICO is a time-critical oxygenation emergency: use trained emergency FONA without delay.

Examiner trap: The original options mixed tracheostomy landmarks with cricothyrotomy; do not trust its listed answer.

Viva extension: How is successful emergency FONA confirmed? Effective ventilation with waveform capnography, chest movement and improved oxygenation.

Question 12 (source Q594). A conscious but profoundly hypothermic trauma patient has a core temperature of 29°C and remains haemodynamically stable. Among the following invasive cavity-based methods, which can provide relatively rapid core rewarming if advanced extracorporeal support is not indicated or available?

Acute Emergencies — Shock and resuscitation

Recorded recall sessions: January 2019; January 2021

A. Warmed peritoneal lavage

B. Increasing room temperature alone

C. Passive cotton blankets alone

D. Warmed oral fluids only

Answer and explanation

A. Warmed peritoneal lavage

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.

B. Increasing ambient temperature is a slow passive approach for profound hypothermia.

C. Passive insulation reduces further heat loss but alone is insufficient for severe hypothermia.

D. Oral fluids are inappropriate if consciousness or airway protection is impaired and have limited rewarming capacity.

Moderate hypothermia: 28–32°C; severe usually below 28°C.
Handle profoundly hypothermic patients gently and monitor ECG.
Active internal warming includes warmed fluids and cavity lavage.
Hypothermic arrest may require ECMO/ECPR at an experienced centre.

Exam pearl: Invasive cavity lavage can rewarm faster than passive methods, but extracorporeal support is preferred in arrest.

Examiner trap: Do not interpret an older recall as saying peritoneal lavage is the universal first-line therapy for all hypothermic patients.

Viva extension: What is the approach in hypothermic cardiac arrest? Prolonged high-quality resuscitation and transfer for extracorporeal rewarming when feasible.

Question 13 (source Q751). On day three after vaginal delivery, a previously well 29-year-old develops high fever, severe pelvic pain, rapidly progressive hypotension, acute kidney injury and a diffuse erythematous rash. Blood cultures grow Gram-positive cocci in chains, and laboratory identification confirms Lancefield group A. Which organism is responsible for the suspected streptococcal toxic shock syndrome?

Acute Emergencies — Shock and resuscitation

Recorded recall sessions: January 2025

A. Staphylococcus aureus

B. Escherichia coli

C. Clostridium perfringens

D. Streptococcus pyogenes

Answer and explanation

D. Streptococcus pyogenes

Group A Streptococcus (Streptococcus pyogenes) causes streptococcal toxic shock syndrome, characterised by invasive infection, shock and multiorgan dysfunction. Childbirth is a recognised context for invasive postpartum infection. The original recall provided only sudden postpartum collapse; culture identity and the shock syndrome were added, so the reconstructed answer is not an authentic recovered key.

A. S. aureus can cause staphylococcal toxic shock, but the culture identifies group A streptococci.

B. E. coli can cause postpartum sepsis but is a Gram-negative bacillus, not group A Gram-positive cocci in chains.

C. C. perfringens can cause gas-forming infection and sepsis but is a Gram-positive bacillus, not group A streptococcus.

Streptococcal toxic shock syndrome requires invasive group A streptococcal infection with shock and organ dysfunction.
Postpartum fever and hypotension demand immediate sepsis assessment and source control.
Management requires urgent resuscitation, antimicrobial therapy and specialist surgical/obstetric review.
Culture identification distinguishes GAS from staphylococcal toxic shock and other postpartum pathogens.

Exam pearl: Invasive group A streptococcus plus rapid shock and organ failure = streptococcal toxic shock syndrome.

Examiner trap: Postpartum collapse alone does not establish the organism; embolism, haemorrhage and other sepsis causes remain possible.

Viva extension: Which antibiotics are used for confirmed GAS toxic shock? Penicillin plus clindamycin is commonly recommended after susceptibility and expert review, alongside urgent source control.

Question 14 (source Q786). After a fall, a 30-year-old has a complete traumatic spinal cord lesion at C2 with flaccid tetraplegia and inability to generate effective spontaneous inspiration. Which spinal cord segments supply the principal motor innervation of the diaphragm?

Acute Emergencies — Shock and resuscitation

Recorded recall sessions: April 2025

A. C6–C8

B. T1–T5

C. C3–C5

D. T6–T12

Answer and explanation

C. C3–C5

The phrenic nerve originates predominantly from C4, with contributions from C3 and C5. A complete lesion above these motor neuron pools disconnects descending respiratory drive and can cause diaphragmatic paralysis and ventilatory dependence. Lower cervical lesions may preserve diaphragm activity but impair intercostal and abdominal muscle function.

A. C6–C8 mainly contributes to brachial plexus functions rather than the phrenic motor pool.

B. T1–T5 innervates upper thoracic intercostal muscles but not the diaphragm through the phrenic nerve.

D. T6–T12 supplies lower intercostal and abdominal wall muscles, important for cough and forced expiration, not the primary diaphragmatic motor supply.

Phrenic nerve root values are C3, C4 and C5, with C4 dominant.
C1–C3 complete injuries commonly require ventilatory support.
C6-level injuries generally spare diaphragm contraction but impair intercostal muscles and cough.
Early airway and ventilatory assessment is essential after high cervical trauma.

Exam pearl: “C3, 4, 5 keep the diaphragm alive.”

Examiner trap: The original recall listed laryngeal cartilages instead of vertebral segments; do not use those options to infer the spinal lesion level.

Viva extension: Which spinal levels innervate intercostal muscles? Thoracic segmental nerves T1–T11; abdominal muscles contribute to forced expiration and cough.

Question 15 (source Q386). A 30-year-old man arrives after blunt abdominal trauma with pulse 118/min, blood pressure 92/60 mmHg and cool peripheries. What is the immediate management priority?

Acute Emergencies — Trauma assessment and resuscitation

Recorded recall sessions: September 2020; September 2021

A. Immediate contrast CT before resuscitation

B. Erect abdominal radiograph as the first intervention

C. ABCDE assessment with haemorrhage control, IV/IO access and blood-product resuscitation

D. Diagnostic peritoneal lavage before vascular access

Answer and explanation

C. ABCDE assessment with haemorrhage control, IV/IO access and blood-product resuscitation

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.

A. Moving an unstable patient to CT delays life-saving haemorrhage control and resuscitation.

B. Plain radiography cannot replace haemodynamic assessment and resuscitation in shock.

D. This is not the first priority and is rarely the initial investigation in modern trauma pathways.

Follow cABCDE or ABCDE with early haemorrhage control.
Activate a major haemorrhage protocol when indicated.
An unstable patient with positive eFAST may need urgent operative or interventional control.
Use warmed blood products and avoid excessive crystalloid in major bleeding.

Exam pearl: Unstable trauma: resuscitate and control haemorrhage before CT.

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

Viva extension: What bedside study can rapidly detect free intraperitoneal fluid? eFAST ultrasound.

Question 16 (source Q514). A patient with malabsorption is prescribed cholecalciferol. In which organ does the first major hydroxylation of vitamin D to 25-hydroxyvitamin D occur?

Basic Sciences & Immunology — Applied anatomy, pathology and physiology

Recorded recall sessions: January 2026

A. Kidney

B. Parathyroid gland

C. Small-intestinal mucosa

D. Liver

Answer and explanation

D. Liver

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

A. The kidney performs the subsequent 1-alpha-hydroxylation to active 1,25-dihydroxyvitamin D.

B. The parathyroid glands regulate renal activation through PTH but are not the principal hydroxylation site.

C. Intestinal absorption is necessary for dietary vitamin D, not its first major hydroxylation.

Skin UVB converts 7-dehydrocholesterol to vitamin D3.
Liver: 25-hydroxylation; kidney: 1-alpha-hydroxylation.
PTH and low phosphate stimulate renal 1-alpha-hydroxylase.
25-OH vitamin D is preferred for assessing vitamin D stores.

Exam pearl: 25 in liver, 1-alpha in kidney.

Examiner trap: Do not use circulating 1,25-(OH)2D as the routine test of vitamin D stores.

Viva extension: What is the active hormone? Calcitriol, 1,25-dihydroxyvitamin D, increases intestinal calcium and phosphate absorption.

Question 17 (source Q768). Normal human fibroblasts are engineered to express strongly activated RAS. They briefly proliferate, then enter persistent G1 arrest with increased p16INK4a and p21, hypophosphorylated RB and little DNA synthesis. What process best explains this response?

Basic Sciences & Immunology — Applied anatomy, pathology and physiology

Recorded recall sessions: September 2022

A. Oncogene-induced senescence mediated by tumour-suppressor checkpoints

B. Unrestricted proliferation caused by loss of both RB alleles

C. Physiological apoptosis mediated exclusively by caspase-3

D. Reversible quiescence caused only by absence of nutrients

Answer and explanation

A. Oncogene-induced senescence mediated by tumour-suppressor checkpoints

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.

B. Loss of RB would tend to release E2F-dependent cell-cycle progression, opposing this observed arrest.

C. Apoptosis is cell death, whereas senescent cells remain viable but persistently growth-arrested.

D. Quiescence is typically reversible when growth stimuli return, unlike established senescence.

Oncogene-induced senescence is a barrier to early tumorigenesis.
p16INK4a/CDK4-6/RB and p53/p21 are major senescence pathways.
Hypophosphorylated RB restrains E2F transcriptional activity.
Senescent cells remain metabolically active and can develop a senescence-associated secretory phenotype.

Exam pearl: Oncogenic RAS in normal checkpoint-intact cells can induce senescence rather than unchecked proliferation.

Examiner trap: Do not confuse viable senescent arrest with apoptosis or simple reversible quiescence.

Viva extension: What molecular change can permit escape from oncogene-induced senescence? Loss or functional inactivation of p53, p16 or RB checkpoint signalling.

Question 18 (source Q793). A 51-year-old man with severe alcohol-use disorder and poor dietary intake has a symmetrical distal sensorimotor neuropathy, impaired vibration sensation and unsteady gait. Laboratory assessment supports a nutritional B-vitamin deficiency. Which vitamin should be replaced urgently, particularly before carbohydrate administration?

Basic Sciences & Immunology — Applied anatomy, pathology and physiology

Recorded recall sessions: September 2017

A. Thiamine (vitamin B1)

B. Niacin (vitamin B3)

C. Ascorbic acid (vitamin C)

D. Retinol (vitamin A)

Answer and explanation

A. Thiamine (vitamin B1)

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.

B. Niacin deficiency causes pellagra, classically dermatitis, diarrhoea and cognitive disturbance rather than the specified thiamine-risk syndrome.

C. Vitamin C deficiency causes scurvy with bleeding gums, bruising and poor wound healing.

D. Vitamin A deficiency produces night blindness and xerophthalmia rather than the classic alcohol-associated thiamine-risk presentation.

Thiamine-dependent enzymes include pyruvate dehydrogenase, alpha-ketoglutarate dehydrogenase and transketolase.
Wernicke encephalopathy classically features confusion, ocular abnormalities and ataxia; the full triad is often absent.
Dry beriberi may present with peripheral neuropathy; wet beriberi may cause high-output heart failure.
Alcohol-related neuropathy is multifactorial; do not attribute every case solely to thiamine deficiency.

Exam pearl: Undernourished alcohol-dependent patient: replace thiamine before or with carbohydrate refeeding.

Examiner trap: The original source asked only “alcohol patient with peripheral neuropathy”; alcohol exposure alone cannot prove a single vitamin deficiency.

Viva extension: Name two thiamine-dependent enzymes. Pyruvate dehydrogenase and transketolase; alpha-ketoglutarate dehydrogenase is another.

Question 19 (source Q182). A histological section of a primary lymphoid organ shows concentric whorls of keratinised epithelial reticular cells in its medulla. Which organ is being examined?

Basic Sciences & Immunology — Immunology, histology and transplantation

Recorded recall sessions: January 2016; April 2017; September 2018; April 2021; May 2022

A. Thymus

B. Parathyroid gland

C. Thyroid gland

D. Pituitary gland

Answer and explanation

A. Thymus

Hassall corpuscles are characteristic concentric epithelial structures within the medulla of the thymus, where thymocytes undergo central tolerance and maturation.

B. Parathyroid tissue contains chief and oxyphil cells, not thymic epithelial whorls.

C. Thyroid tissue is composed of colloid-containing follicles and parafollicular C cells.

D. The pituitary contains anterior endocrine cells and posterior neural tissue, not Hassall corpuscles.

The thymus has a cortex rich in immature T lymphocytes and a paler medulla.
Thymic epithelial cells participate in negative selection and central tolerance.
The thymus involutes after puberty, but residual medullary structures may persist.

Exam pearl: Hassall corpuscles = thymic medulla.

Examiner trap: Do not confuse thymic cortex with parathyroid chief-cell sheets.

Viva extension: Which embryological pouch forms the thymus? The third pharyngeal pouch (ventral wing).

Question 20 (source Q183). A patient with an intracellular mycobacterial infection mounts a Th1 immune response. Interferon-gamma most directly enhances the microbicidal activity of which effector cell?

Basic Sciences & Immunology — Immunology, histology and transplantation

Recorded recall sessions: January 2024

A. Eosinophil

B. Macrophage

C. Plasma cell

D. Basophil

Answer and explanation

B. Macrophage

IFN-γ produced by Th1 cells and NK cells activates macrophages, increasing phagolysosomal killing, antigen presentation and inflammatory cytokine responses against intracellular pathogens.

A. Eosinophils are primarily important in helminth defence and allergy.

C. Plasma cells differentiate from B lymphocytes to secrete immunoglobulins rather than being the principal IFN-γ target.

D. Basophils participate in immediate hypersensitivity and release histamine.

Th1 cells characteristically produce IFN-γ.
IL-12 promotes Th1 differentiation and IFN-γ responses.
Macrophage activation is central to granuloma formation in tuberculosis.

Exam pearl: IFN-γ activates macrophages; IL-4/IL-13 favour alternative macrophage activation.

Examiner trap: Do not confuse IFN-γ with type I interferons (IFN-α/β), which are prominent in antiviral signalling.

Viva extension: Which cytokine drives Th1 differentiation? IL-12.

Question 21 (source Q261). A 20-year-old receives a human cadaveric aortic valve to replace a severely stenotic native valve. How is this graft classified by donor–recipient relationship?

Basic Sciences & Immunology — Immunology, histology and transplantation

Recorded recall sessions: April 2021

A. Autograft

B. Allograft (homograft)

C. Xenograft

D. Isograft

Answer and explanation

B. Allograft (homograft)

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.

A. Tissue transferred within the same person, for example a pulmonary autograft in the Ross operation.

C. Tissue derived from a different species, such as a porcine bioprosthetic valve.

D. Tissue transplanted between genetically identical individuals, such as monozygotic twins.

Autograft: same individual.
Allograft: genetically non-identical individuals of same species.
Xenograft: different species.
Isograft: genetically identical individuals.

Exam pearl: Human cadaver valve = allograft, not xenograft.

Examiner trap: Bioprosthetic does not necessarily mean xenograft; human homograft valves are biological allografts.

Viva extension: What is the Ross procedure? Pulmonary autograft replaces the aortic valve, with RV outflow reconstruction.

Question 22 (source Q263). A 38-year-old man has weight loss, persistent cough and a corrugated white plaque on the lateral tongue that cannot be scraped off. Which underlying condition should be investigated urgently?

Basic Sciences & Immunology — Immunology, histology and transplantation

Recorded recall sessions: not recorded

A. Isolated iron-deficiency anaemia

B. Acute streptococcal tonsillitis

C. Uncomplicated oral candidiasis alone

D. HIV-associated immunosuppression

Answer and explanation

D. HIV-associated immunosuppression

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.

A. May cause glossitis but does not typically produce corrugated EBV-associated lateral-tongue plaques.

B. Produces pharyngeal symptoms and tonsillar exudate, not chronic lateral-tongue leukoplakia.

C. Candidal plaques often scrape off; hairy leukoplakia is usually non-scrapable and EBV-associated.

EBV causes oral hairy leukoplakia.
The lateral border of the tongue is a classic location.
It can occur with other immunosuppressive states, not only HIV.
A persistent atypical lesion may require biopsy to exclude dysplasia or malignancy.

Exam pearl: Corrugated non-scrapable lateral tongue plaque = think oral hairy leukoplakia and HIV.

Examiner trap: Not every white oral lesion is thrush; scrapability and location help differentiate.

Viva extension: Which virus causes oral hairy leukoplakia? Epstein–Barr virus.

Question 23 (source Q353). Six weeks after renal transplantation, a woman taking tacrolimus, mycophenolate and prednisolone develops fever, fatigue and malaise. Plasma CMV PCR is strongly positive. What is the most likely cause of her systemic illness?

Basic Sciences & Immunology — Immunology, histology and transplantation

Recorded recall sessions: September 2018; May 2022

A. Cytomegalovirus infection

B. Acute hepatitis B

C. Post-transplant lymphoproliferative disorder

D. Primary HIV infection

Answer and explanation

A. Cytomegalovirus infection

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.

B. HBV requires appropriate serology and typically has a different diagnostic pattern; it does not explain a positive CMV viral load.

C. PTLD is an important differential, especially with persistent lymphadenopathy, but a compatible syndrome plus substantial CMV viraemia favours CMV disease.

D. HIV is diagnosed by HIV testing; it cannot be inferred from transplant immunosuppression and a positive CMV PCR.

Risk is influenced by donor/recipient serostatus and prophylaxis.
CMV may cause colitis, hepatitis, pneumonitis or marrow suppression.
Treatment of significant CMV disease often involves valganciclovir or IV ganciclovir with specialist oversight.
Monitor viral load and adjust treatment for renal function.

Exam pearl: Post-transplant fever + positive CMV PCR should prompt evaluation for CMV disease.

Examiner trap: Fever and lymphadenopathy alone are not specific: the source recall lacked virological confirmation, added here to make one defensible SBA.

Viva extension: How is CMV risk stratified after transplantation? By donor and recipient CMV serostatus, immunosuppression and preventive strategy.

Question 24 (source Q450). Within minutes of a local inflammatory reaction, skin becomes red and warm as arterioles dilate and vascular permeability increases. Which mediator released from mast cells is chiefly responsible for this immediate response?

Basic Sciences & Immunology — Immunology, histology and transplantation

Recorded recall sessions: January 2023; January 2024

A. Endothelin-1

B. Thromboxane A2

C. Histamine

D. Vasopressin

Answer and explanation

C. Histamine

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.

A. Endothelin is a potent vasoconstrictor rather than the classic mediator of early inflammatory erythema.

B. Thromboxane promotes platelet aggregation and vasoconstriction.

D. Vasopressin has antidiuretic and vasoconstrictor actions, not the main acute local inflammatory effect.

Histamine is stored preformed in mast-cell granules.
H1 receptor signalling increases endothelial permeability.
Bradykinin also increases permeability and causes pain.
Prostaglandins contribute to pain, fever and vasodilatation.

Exam pearl: Histamine = immediate vasodilatation and increased vascular permeability.

Examiner trap: Do not select endothelin or thromboxane when the question asks for vasodilatation.

Viva extension: Which mediator causes pain in acute inflammation? Bradykinin and prostaglandin E2 are important contributors.

Question 25 (source Q452). An 11-year-old develops urticaria, lip swelling and wheeze within minutes of a bee sting. Which immunological mechanism best explains this reaction?

Basic Sciences & Immunology — Immunology, histology and transplantation

Recorded recall sessions: January 2017

A. Type II antibody-mediated cytotoxicity

B. Type III immune-complex hypersensitivity

C. Type I IgE-mediated hypersensitivity

D. Type IV delayed T-cell hypersensitivity

Answer and explanation

C. Type I IgE-mediated hypersensitivity

Allergen cross-linking of IgE on sensitised mast cells triggers degranulation, histamine release and other mediators, producing immediate urticaria, angioedema, bronchospasm and potentially anaphylaxis.

A. IgG or IgM directed against cell-surface antigens causes disorders such as autoimmune haemolytic anaemia.

B. Circulating antigen–antibody complexes cause conditions such as serum sickness, usually not immediate wheeze after a sting.

D. This is a delayed cell-mediated response, classically exemplified by contact dermatitis and the Mantoux reaction.

Anaphylaxis is a clinical diagnosis and requires prompt IM adrenaline.
IgE binds high-affinity Fc-epsilon-RI on mast cells.
Early and late phases of allergy involve different mediator profiles.
Antihistamines do not replace adrenaline in anaphylaxis.

Exam pearl: Minutes after a sting with urticaria and wheeze = type I hypersensitivity.

Examiner trap: Isolated local swelling is not necessarily anaphylaxis; airway, breathing or circulation involvement matters.

Viva extension: What is first-line treatment for anaphylaxis? Intramuscular adrenaline in the anterolateral thigh, with airway and resuscitation measures.

Question 26 (source Q453). A patient develops an indurated reaction 48–72 hours after intradermal tuberculin purified protein derivative. Which hypersensitivity type causes this response?

Basic Sciences & Immunology — Immunology, histology and transplantation

Recorded recall sessions: April 2017

A. Type II cytotoxic antibody reaction

B. Type IV delayed-type hypersensitivity

C. Type I IgE-mediated reaction

D. Type III immune-complex reaction

Answer and explanation

B. Type IV delayed-type hypersensitivity

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.

A. Type II involves antibodies against cell-surface or matrix antigens.

C. Type I responses occur within minutes and are mediated by mast-cell degranulation.

D. Type III results from immune-complex deposition and complement activation.

Read the induration, not the erythema, at 48–72 hours.
Prior BCG vaccination and nontuberculous mycobacteria can affect specificity.
Immunosuppression can cause false-negative skin tests.
Interferon-gamma release assays are alternatives in many settings.

Exam pearl: Mantoux = type IV hypersensitivity mediated by T cells.

Examiner trap: An erythematous flare immediately after injection is not the diagnostic delayed induration.

Viva extension: Which cells mediate the reaction? Memory T cells and recruited macrophages.

Question 27 (source Q732). A theatre nurse develops an itchy eczematous rash with small vesicles on the backs of both hands 36 hours after wearing rubber surgical gloves. There is no immediate urticaria, wheeze or hypotension. Patch testing identifies a rubber accelerator. Which immunological mechanism is responsible?

Basic Sciences & Immunology — Immunology, histology and transplantation

Recorded recall sessions: May 2022

A. Type I IgE-mediated hypersensitivity

B. Type III immune-complex hypersensitivity

C. Type IV T-cell-mediated delayed hypersensitivity

D. Type II antibody-mediated cytotoxicity

Answer and explanation

C. Type IV T-cell-mediated delayed hypersensitivity

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.

A. Type I allergy to latex proteins develops within minutes and may cause urticaria, bronchospasm or anaphylaxis, not a delayed patch-test-positive eczematous rash.

B. Type III disease involves circulating immune complexes and complement deposition, not a localised delayed contact dermatitis.

D. Type II reactions involve IgG/IgM directed against cell-surface or matrix antigens, classically causing cytopenias or tissue-specific injury.

Type IV contact allergy is mediated by sensitised T lymphocytes, not IgE.
Rubber accelerators such as thiurams and carbamates can cause delayed glove dermatitis.
Immediate latex-protein allergy is type I and may be life-threatening.
Irritant hand dermatitis from frequent washing is not an immune hypersensitivity.
Patch testing helps identify delayed contact allergens; immediate allergy requires a different assessment.

Exam pearl: Delayed vesicular hand eczema after gloves = type IV; immediate urticaria/wheeze = type I.

Examiner trap: “Glove allergy” alone cannot establish hypersensitivity type; timing and phenotype must be specified.

Viva extension: Which test evaluates suspected type IV contact allergy? Patch testing to the suspected chemical allergens, interpreted with clinical exposure history.

Question 28 (source Q766). A veterinary surgeon develops generalised wheals, wheezing and lip swelling within 5 minutes of putting on natural-rubber latex gloves. Which immunological mechanism is most likely?

Basic Sciences & Immunology — Immunology, histology and transplantation

Recorded recall sessions: May 2022

A. Type II antibody-mediated cytotoxicity

B. Type I IgE-mediated immediate hypersensitivity

C. Type III immune-complex deposition

D. Type IV delayed T-cell-mediated contact hypersensitivity

Answer and explanation

B. Type I IgE-mediated immediate hypersensitivity

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. Type II reactions involve antibodies against cell-surface antigens, not typical rapid latex urticaria.

C. Type III immune-complex disease has a different mechanism and time course.

D. Type IV allergy causes delayed eczematous dermatitis, often to rubber-processing chemicals, rather than immediate systemic wheeze and angioedema.

Natural-rubber latex proteins can provoke immediate IgE-mediated type I reactions.
Rubber accelerators may cause delayed type IV allergic contact dermatitis.
Irritant hand dermatitis is common and is not an immune hypersensitivity reaction.
Suspected latex anaphylaxis requires latex-free care and formal allergy assessment.

Exam pearl: Minutes + wheals/wheeze = type I; delayed eczema after glove exposure = type IV.

Examiner trap: The original glove-allergy recall did not describe onset or phenotype; the answer cannot be inferred from occupation alone.

Viva extension: How are immediate and delayed latex allergy investigated? Type I: specialist history, specific IgE and/or skin-prick testing; type IV: patch testing for contact allergens.

Question 29 (source Q681). A patient with chronic postoperative pain uses transcutaneous electrical nerve stimulation (TENS). Its conventional segmental analgesic effect is best explained by which mechanism?

Basic Sciences & Immunology — Pain mechanisms and inflammation

Recorded recall sessions: January 2021

A. Direct irreversible blockade of peripheral sodium channels

B. Activation of large-diameter afferents that inhibit nociceptive transmission in the dorsal horn

C. Increased release of substance P from C-fibre terminals

D. Destruction of spinothalamic tract neurones

Answer and explanation

B. Activation of large-diameter afferents that inhibit nociceptive transmission in the dorsal horn

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.

A. Sodium-channel blockade is characteristic of local anaesthetics, not the primary mechanism of TENS.

C. Substance P facilitates nociceptive signalling rather than explaining TENS analgesia.

D. TENS is non-destructive and does not ablate the ascending spinothalamic pathway.

The dorsal horn, particularly substantia gelatinosa, modulates nociceptive transmission.
Large myelinated A-beta afferents participate in segmental gating.
TENS is an adjunct, not a substitute for assessment of new neurological red flags.
Analgesic effect varies with stimulation frequency and intensity.

Exam pearl: TENS works chiefly through spinal dorsal-horn modulation, not by cutting or chemically blocking nerves.

Examiner trap: Do not confuse TENS with spinal cord stimulation or a local anaesthetic nerve block.

Viva extension: What is gate-control theory? Non-nociceptive large-fibre input activates inhibitory interneurones that diminish dorsal-horn projection-neurone activity.

Question 30 (source Q719). A patient has acute local tissue injury with warmth, swelling and pain. Which inflammatory mediator contributes to both vasodilatation and stimulation of pain-sensitive nerve endings?

Basic Sciences & Immunology — Pain mechanisms and inflammation

Recorded recall sessions: September 2022

A. Bradykinin

B. Thromboxane A2

C. Endothelin-1

D. Angiotensin II

Answer and explanation

A. Bradykinin

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.

B. Thromboxane A2 promotes platelet aggregation and vasoconstriction, not the classic pain-and-vasodilatation combination.

C. Endothelin-1 is a potent vasoconstrictor.

D. Angiotensin II is a potent vasoconstrictor and stimulates aldosterone release.

Bradykinin is generated from kininogen by kallikrein.
It increases vascular permeability and produces pain.
Histamine also increases permeability and vasodilatation but is not an option in this item.
ACE degrades bradykinin; ACE-inhibitor-associated cough/angioedema partly reflects its accumulation.

Exam pearl: Bradykinin causes pain, permeability and vasodilatation.

Examiner trap: Thromboxane A2 and prostacyclin have opposing platelet and vascular effects; do not confuse them.

Viva extension: Why can ACE inhibitors cause angioedema? Reduced breakdown of bradykinin increases vascular permeability.

Question 31 (source Q306). An explanted cirrhotic liver shows abundant coarse golden-brown hepatocellular granules. The deposits stain blue with Perls Prussian blue. Which substance has accumulated?

Haematology — Blood, coagulation and haematological malignancy

Recorded recall sessions: April 2017; September 2024

A. Ferric iron (haemosiderin)

B. Copper

C. Bilirubin

D. Amyloid

Answer and explanation

A. Ferric iron (haemosiderin)

Perls Prussian blue reacts with ferric iron in tissue, staining haemosiderin deposits blue. Marked hepatocellular iron loading raises concern for hereditary or secondary haemochromatosis, although histology alone cannot establish its aetiology.

B. Copper accumulation occurs in Wilson disease and requires different histochemical tests, such as rhodanine or rubeanic acid.

C. Bile pigment is not specifically identified by Perls Prussian blue.

D. Amyloid is demonstrated by Congo red with characteristic apple-green birefringence under polarised light.

Assess transferrin saturation and ferritin in suspected iron overload.
HFE-associated hereditary haemochromatosis commonly involves increased intestinal iron absorption.
Iron overload can cause cirrhosis, diabetes and cardiomyopathy.
Congo red is the classical stain for amyloid, not iron.

Exam pearl: Prussian blue = ferric iron; Congo red = amyloid.

Examiner trap: Blue tissue stain is not a diagnosis by itself; interpret distribution and iron studies.

Viva extension: Which molecular pathway is often involved in hereditary haemochromatosis? HFE/hepcidin regulation.

Question 32 (source Q415). A patient on warfarin has INR 6.1. Which biochemical action explains warfarin-associated reduction in functional prothrombin and other clotting factors?

Haematology — Blood, coagulation and haematological malignancy

Recorded recall sessions: January 2019; January 2021

A. Direct inhibition of thrombin active sites

B. Inhibition of vitamin K epoxide reductase, impairing gamma-carboxylation

C. Direct inhibition of activated factor Xa

D. Antithrombin potentiation

Answer and explanation

B. Inhibition of vitamin K epoxide reductase, impairing gamma-carboxylation

Warfarin inhibits VKORC1, limiting regeneration of reduced vitamin K needed for gamma-carboxylation of factors II, VII, IX and X and proteins C and S. These under-carboxylated proteins cannot bind calcium and phospholipid surfaces normally, impairing coagulation.

A. This is the mechanism of direct thrombin inhibitors, not warfarin.

C. This is the mechanism of factor-Xa inhibitors such as apixaban.

D. Heparins enhance antithrombin activity; warfarin affects vitamin K recycling.

Warfarin affects factors II, VII, IX, X and proteins C and S.
Factor VII falls relatively early, influencing the INR.
Warfarin has a delayed onset because circulating factors must decay.
INR standardises prothrombin-time monitoring for vitamin K antagonists.

Exam pearl: Warfarin inhibits VKORC1, not thrombin directly.

Examiner trap: Early protein C reduction can transiently favour thrombosis before full anticoagulation.

Viva extension: Which clotting factor has the longest half-life among II, VII, IX and X? Factor II (prothrombin).

Question 33 (source Q458). A patient taking low-dose aspirin has prolonged platelet dysfunction despite a normal platelet count. What is the primary mechanism?

Haematology — Blood, coagulation and haematological malignancy

Recorded recall sessions: January 2019; January 2020

A. Direct inhibition of thrombin

B. Irreversible acetylation of platelet cyclooxygenase-1

C. Inhibition of vitamin K epoxide reductase

D. Reversible blockade of the P2Y12 receptor

Answer and explanation

B. Irreversible acetylation of platelet cyclooxygenase-1

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.

A. Dabigatran is a direct thrombin inhibitor; aspirin is not.

C. Warfarin reduces synthesis of vitamin-K-dependent coagulation factors, not platelet COX-1.

D. P2Y12 blockade is the mechanism of clopidogrel and related antiplatelet drugs.

Platelet lifespan is approximately 7–10 days.
Thromboxane A2 promotes aggregation and vasoconstriction.
Aspirin affects primary haemostasis rather than directly prolonging PT/INR.
Platelet count can remain normal despite impaired function.

Exam pearl: Aspirin irreversibly blocks COX-1 and thromboxane A2 synthesis.

Examiner trap: Do not mistake platelet dysfunction for aspirin-induced thrombocytopenia.

Viva extension: Why is the effect prolonged after aspirin clears? Platelets lack nuclei and cannot replace acetylated COX-1.

Question 34 (source Q481). A 78-year-old has bone pain, multiple lytic lesions, a monoclonal light-chain paraprotein and renal impairment. Renal biopsy shows Congo-red-positive extracellular deposits. Which amyloid subtype is most likely?

Haematology — Blood, coagulation and haematological malignancy

Recorded recall sessions: September 2020; April 2021; September 2021

A. AA amyloid from serum amyloid A

B. AL amyloid derived from monoclonal immunoglobulin light chains

C. Beta-2 microglobulin amyloid

D. ATTR amyloid from transthyretin

Answer and explanation

B. AL amyloid derived from monoclonal immunoglobulin light chains

Plasma-cell dyscrasias such as multiple myeloma produce monoclonal immunoglobulin light chains. Misfolded light chains can deposit as AL amyloid in kidneys and other organs, causing proteinuria and organ dysfunction.

A. AA deposition is linked to chronic inflammatory disorders such as rheumatoid arthritis.

C. This is most associated with long-term dialysis, especially osteoarticular deposits.

D. Transthyretin amyloid classically affects the heart and peripheral/autonomic nerves.

AL amyloidosis may complicate plasma-cell disorders.
Congo red with apple-green birefringence confirms amyloid.
Light-chain cast nephropathy is another important cause of renal failure in myeloma.
Serum free-light-chain testing and immunofixation help characterise monoclonal disease.

Exam pearl: Myeloma plus amyloid = AL; chronic inflammation plus amyloid = AA.

Examiner trap: Not all renal failure in myeloma is amyloidosis; cast nephropathy is common and must be distinguished.

Viva extension: What other renal mechanism occurs in myeloma? Filtered light chains form obstructing casts and cause tubular injury.

Question 35 (source Q544). A 22-year-old woman has recurrent bacterial throat infections, spontaneous bruising and fatigue. Examination shows no splenomegaly. Blood counts reveal neutropenia, thrombocytopenia and anaemia with a low reticulocyte count. Which diagnosis best unifies the findings?

Haematology — Blood, coagulation and haematological malignancy

Recorded recall sessions: September 2021

A. Aplastic anaemia

B. Chronic myeloid leukaemia

C. Immune thrombocytopenia

D. Hodgkin lymphoma

Answer and explanation

A. Aplastic anaemia

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.

B. CML typically features marked myeloid leukocytosis and often splenomegaly, not hypocellular pancytopenia.

C. Immune thrombocytopenia is usually isolated thrombocytopenia with preserved red and white cell lines.

D. Hodgkin lymphoma classically produces lymphadenopathy and may cause cytopenias only with advanced involvement or treatment.

Aplastic anaemia is hypocellular bone marrow failure.
Classical presentation combines infection, bleeding and anaemia.
A low reticulocyte count indicates impaired production.
Marrow biopsy and exclusion of reversible causes are required.

Exam pearl: Pancytopenia plus low reticulocytes and no splenomegaly strongly suggests marrow failure.

Examiner trap: Isolated bruising does not prove aplasia; inspect all three cell lines.

Viva extension: What are major treatments for severe aplastic anaemia? Haematopoietic stem-cell transplantation in suitable patients or immunosuppression with ATG/ciclosporin-based regimens.

Question 36 (source Q584). A 7-year-old develops pallor, oliguria, thrombocytopenia and fragmented red cells several days after bloody diarrhoea. Which pathogen is the classic trigger?

Haematology — Blood, coagulation and haematological malignancy

Recorded recall sessions: May 2022

A. Streptococcus pyogenes

B. Neisseria gonorrhoeae

C. Shiga-toxin-producing Escherichia coli

D. Chlamydia trachomatis

Answer and explanation

C. Shiga-toxin-producing Escherichia coli

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.

A. Group A streptococcus is not the classic post-bloody-diarrhoea HUS pathogen.

B. Gonococcus causes disseminated infection and septic arthritis rather than classic STEC-HUS.

D. Chlamydia does not cause the typical HUS triad following bloody diarrhoea.

HUS triad: microangiopathic haemolysis, thrombocytopenia and AKI.
Schistocytes and raised LDH support intravascular haemolysis.
Management is predominantly supportive, including fluid and renal support.
Avoid antimotility agents in suspected STEC infection; antibiotic decisions require specialist guidance.

Exam pearl: Bloody diarrhoea followed by HUS strongly suggests STEC.

Examiner trap: Do not confuse STEC-HUS with TTP; severe ADAMTS13 deficiency is characteristic of immune TTP.

Viva extension: Which test identifies the trigger? Stool Shiga-toxin PCR or culture as locally available.

Question 37 (source Q629). A 55-year-old man has fatigue, bone pain, multiple punched-out osteolytic lesions and monoclonal free light chains in urine. What is the most likely diagnosis?

Haematology — Blood, coagulation and haematological malignancy

Recorded recall sessions: September 2017; September 2019; September 2020; May 2022

A. Osteomalacia

B. Multiple myeloma

C. Paget disease of bone

D. Secondary hyperparathyroidism

Answer and explanation

B. Multiple myeloma

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.

A. Osteomalacia produces defective mineralisation rather than a plasma-cell paraprotein with punched-out lesions.

C. Paget disease produces disordered remodelling with mixed sclerotic and lytic changes but not monoclonal free light chains.

D. Secondary hyperparathyroidism may cause renal osteodystrophy but not a Bence Jones paraprotein pattern.

CRAB features: hyperCalcaemia, Renal failure, Anaemia, Bone lesions.
Urinary Bence Jones proteins are monoclonal immunoglobulin light chains.
Serum free light chains and serum/urine electrophoresis aid assessment.
Myeloma commonly causes well-defined lytic lesions with fracture risk.

Exam pearl: Bence Jones proteinuria plus punched-out skull lesions suggests myeloma.

Examiner trap: Do not mistake osteoporotic vertebral collapse alone for diagnostic evidence of myeloma.

Viva extension: What are the principal end-organ damage features? Hypercalcaemia, renal impairment, anaemia and lytic bone disease.

Question 38 (source Q630). A 55-year-old woman has slowly progressive, painless rubbery lymphadenopathy in cervical, axillary and inguinal chains, with night sweats. What is the most likely diagnostic category?

Haematology — Blood, coagulation and haematological malignancy

Recorded recall sessions: September 2018

A. Localised skin squamous carcinoma

B. Acute cellulitis

C. Simple reactive unilateral adenitis

D. Lymphoma

Answer and explanation

D. Lymphoma

Persistent generalised, painless, rubbery nodal enlargement with B symptoms is strongly suggestive of lymphoma, although definitive diagnosis requires appropriate tissue assessment.

A. Cutaneous squamous cancer generally produces drainage-basin regional nodal disease rather than diffuse rubbery chains.

B. Acute cellulitis causes local erythema and tenderness, often with regional reactive nodes.

C. Reactive unilateral adenitis does not account for multiregional persistent nodes and night sweats.

B symptoms include unexplained fever, drenching night sweats and unintentional weight loss.
Lymphoma can present with painless cervical or generalised adenopathy.
Excisional biopsy is often preferred when lymphoma is suspected because architecture is important.
The diagnosis and subtype require morphology and immunophenotyping.

Exam pearl: Rubbery painless nodes in several regions plus B symptoms: think lymphoma.

Examiner trap: Do not assume absence of pain excludes malignancy.

Viva extension: Why might a core or excision be preferred over FNAC? Lymphoma classification often needs tissue architecture, flow cytometry and immunohistochemistry.

Question 39 (source Q911). A 68-year-old with restrictive cardiomyopathy undergoes endomyocardial biopsy. Extracellular deposits stain orange-red with Congo red. Under crossed polarised light, which finding confirms amyloid?

Haematology — Blood, coagulation and haematological malignancy

Recorded recall sessions: September 2024

A. Strong blue fluorescence without polarisation

B. Red granular staining with Ziehl–Neelsen

C. Apple-green birefringence

D. Black staining with silver impregnation

Answer and explanation

C. Apple-green birefringence

Congo red binds the ordered cross-beta-pleated-sheet structure of amyloid fibrils. When an appropriately prepared section is viewed with polarised light, the deposits show characteristic apple-green birefringence. The colour arises from optical properties of the dye–fibril complex; the same result does not establish whether the amyloid is AL, AA or transthyretin.

A. Fluorescence is not the diagnostic Congo-red polarisation pattern.

B. Ziehl–Neelsen highlights acid-fast organisms, not amyloid deposits.

D. Silver impregnation highlights selected tissue structures and organisms; it does not provide the classic amyloid criterion.

Congo red is the conventional tissue stain for amyloid.
Polarised light is essential to demonstrate the characteristic birefringence.
Typing amyloid requires additional immunohistochemical or mass-spectrometry methods.
AL amyloid can be associated with plasma-cell dyscrasia; ATTR with cardiac disease.

Exam pearl: Congo red + apple-green birefringence = amyloid.

Examiner trap: Do not confuse amyloid confirmation with determination of the precursor protein.

Viva extension: How is amyloid subtype established? By validated tissue typing, ideally mass spectrometry when available, interpreted with the clinical work-up.

Question 40 (source Q923). A patient starts warfarin for a mechanical heart valve. Within the first day, the INR rises although full antithrombotic effect has not developed. Which clotting factor’s relatively short half-life contributes most to this early INR change?

Haematology — Blood, coagulation and haematological malignancy

Recorded recall sessions: January 2021

A. Factor VIII

B. Factor V

C. Factor XIII

D. Factor VII

Answer and explanation

D. Factor VII

Warfarin reduces vitamin-K-dependent synthesis of factors II, VII, IX and X as well as proteins C and S. Factor VII has a relatively short circulating half-life (about 4–6 hours), so prothrombin-time/INR may rise early. Factor II has a much longer half-life, and full antithrombotic effect takes several days. Mechanical valve anticoagulation needs specialist INR targets and bridging decisions when indicated.

A. Factor VIII is not vitamin-K-dependent and is not the main cause of the early PT response.

B. Factor V is not vitamin-K-dependent.

C. Factor XIII is not the short-lived vitamin-K-dependent factor driving early INR changes.

Vitamin-K-dependent factors: II, VII, IX and X; proteins C and S are also affected.
PT/INR is particularly sensitive to factor VII depletion early in therapy.
Factor II depletion is important for full anticoagulant effect.
Early reduction in protein C can transiently increase thrombogenicity.

Exam pearl: Early INR rise on warfarin reflects short-lived factor VII, not immediate full anticoagulation.

Examiner trap: Do not assume an INR rise on day 1 means full protection from thrombosis.

Viva extension: Why may heparin overlap be needed when initiating warfarin for selected high-risk thromboses? To provide immediate anticoagulation while vitamin-K-dependent clotting factors decline.

Question 41 (source Q949). A patient has easy bruising and mucosal bleeding with a normal platelet count. Specialist testing suggests a platelet dense-granule secretion defect. Which substance is normally stored in these dense granules and released to amplify platelet activation?

Haematology — Haematology and coagulation

Recorded recall sessions: April 2026

A. Fibrinogen

B. von Willebrand factor

C. Platelet-derived growth factor

D. ADP

Answer and explanation

D. ADP

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.

A. Fibrinogen is primarily an alpha-granule protein and plasma coagulation substrate.

B. von Willebrand factor is found in alpha granules and endothelial Weibel–Palade bodies.

C. Platelet-derived growth factor is a protein cargo of alpha granules.

Dense granules contain ADP, ATP, serotonin and calcium.
Alpha granules contain vWF, fibrinogen, factor V and growth factors.
Dense-granule deficiency can cause a platelet-type mucocutaneous bleeding phenotype.
Platelet number can be normal despite a significant qualitative secretion defect.

Exam pearl: Dense = small molecules (ADP, calcium, serotonin); alpha = adhesive proteins and growth factors.

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

Viva extension: Which drug receptor pathway is activated by released ADP? The P2Y12 receptor, inhibited by clopidogrel and related agents.

Question 42 (source Q954). A 26-year-old woman at 20 weeks of pregnancy has macrocytic anaemia, distal paraesthesiae, impaired vibration sense and a clearly low serum vitamin B12 level. Folate is normal. What is the most appropriate specific replacement while urgent specialist advice is arranged?

Haematology — Haematology and coagulation

Recorded recall sessions: 2021 (session not specified)

A. High-dose folic acid alone without vitamin B12

B. Intramuscular hydroxocobalamin

C. Iron infusion as the sole treatment

D. Observation until after delivery

Answer and explanation

B. Intramuscular hydroxocobalamin

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.

A. Folate alone cannot correct B12-dependent neurological injury and may mask the haematological signs.

C. Iron is not the specific treatment for confirmed B12 deficiency with neuropathy.

D. Delaying treatment risks persistent neurological dysfunction and maternal harm.

Megaloblastic anaemia can result from either folate or B12 deficiency.
Neurological signs favour B12 deficiency over isolated folate deficiency.
With neurological involvement in pregnancy, seek urgent advice and consider IM hydroxocobalamin.
Assess underlying cause and response; do not rely solely on MCV to exclude deficiency.

Exam pearl: Macrocytosis + neuropathy + low B12 in pregnancy → urgent B12 replacement, not folate alone.

Examiner trap: The original recall omitted laboratory discrimination; never choose folate versus B12 from MCV alone.

Viva extension: Why is isolated folate replacement unsafe in B12 deficiency? It can improve blood counts while neurological injury progresses.

Question 43 (source Q74). A patient has persistent painless cervical, axillary and inguinal lymphadenopathy. What underlying diagnosis should be strongly considered?

Haematology — Lymphatic and lymphoproliferative disorders

Recorded recall sessions: September 2019; September 2020; September 2021

A. Acute bacterial lymphadenitis

B. Lymphoma

C. Cat-scratch lymphadenitis

D. Isolated reactive node after an upper respiratory infection

Answer and explanation

B. Lymphoma

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.

A. Usually painful and associated with local inflammation, often in one drainage basin.

C. Usually affects regional nodes near an inoculation site rather than several nodal regions.

D. Typically resolves and does not explain persistent widespread adenopathy.

Excisional node biopsy may be required to preserve architecture
Ask about fever, night sweats and weight loss
Assess spleen and liver enlargement.

Exam pearl: Persistent generalised painless lymphadenopathy requires lymphoma assessment.

Examiner trap: FNAC alone may be insufficient to classify lymphoma fully.

Viva extension: What are B symptoms? Unexplained fever, drenching night sweats and significant unintentional weight loss.

Question 44 (source Q805). A 19-year-old student has fever, profound fatigue, exudative pharyngitis, posterior cervical lymphadenopathy and a palpable spleen. Blood film shows atypical reactive lymphocytes. Which diagnosis best explains the constellation?

Haematology — Lymphatic and lymphoproliferative disorders

Recorded recall sessions: 2022/2023 (mixed/uncertain session)

A. Epstein–Barr virus infectious mononucleosis

B. Acute bacterial tonsillitis without systemic infection

C. Cat-scratch lymphadenitis

D. Chronic lymphocytic leukaemia

Answer and explanation

A. Epstein–Barr virus infectious mononucleosis

Primary EBV infection commonly causes infectious mononucleosis in adolescents and young adults. The typical syndrome combines fever, pharyngitis, fatigue and cervical lymphadenopathy; splenomegaly and reactive lymphocytosis provide supportive findings. Treatment is usually supportive, and contact sports should be avoided while splenic injury risk is relevant.

B. Bacterial tonsillitis may cause fever and exudate but does not typically explain prominent posterior cervical nodes, splenomegaly and atypical lymphocytosis.

C. Bartonella commonly produces regional lymphadenopathy following cat exposure, not the typical pharyngitis–splenomegaly syndrome.

D. CLL usually occurs in older adults with persistent clonal lymphocytosis; the acute pharyngitis syndrome in a teenager is not characteristic.

EBV infects B lymphocytes via CD21 and triggers a reactive T-cell response.
Posterior cervical lymphadenopathy is a useful clinical clue.
Atypical lymphocytes are reactive lymphocytes, not necessarily malignant blasts.
EBV VCA IgM without EBNA antibodies supports recent primary infection when testing is indicated.

Exam pearl: Pharyngitis + posterior cervical nodes + splenomegaly in a young adult = consider EBV.

Examiner trap: EBV serology, not a single heterophile test, is preferred for clarifying atypical cases.

Viva extension: What serious sports-related complication must be discussed? Splenic rupture; advise avoiding contact/collision sports during the period of splenic enlargement and recovery.

Question 45 (source Q764). A woman at 18 weeks of pregnancy has fatigue, Hb 9.4 g/dL, MCV 112 fL and hypersegmented neutrophils. Serum folate is low, vitamin B12 is normal, and she has no neurological symptoms. What is the most appropriate specific replacement?

Haematology — Nutritional and megaloblastic anaemias

Recorded recall sessions: April 2017

A. Therapeutic oral folic acid

B. Intramuscular hydroxocobalamin as the sole replacement

C. Intravenous iron alone

D. Packed red-cell transfusion in every case

Answer and explanation

A. Therapeutic oral folic acid

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.

B. Hydroxocobalamin treats B12 deficiency, which is not demonstrated here; it would not be the targeted sole treatment for isolated folate deficiency.

C. Iron treats iron deficiency and does not correct isolated megaloblastic folate deficiency.

D. Stable anaemia does not mandate transfusion; transfusion depends on symptoms, physiology and bleeding.

Always check vitamin B12 before treating presumed folate deficiency because folate can mask B12-associated anaemia while neurological injury progresses.
Folate demand rises during pregnancy.
Hypersegmented neutrophils and macro-ovalocytes support megaloblastic haematopoiesis.
Treatment-dose folate is different from prophylactic folate used before conception and early pregnancy.

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

Examiner trap: Macrocytosis alone does not distinguish folate deficiency from B12 deficiency.

Viva extension: What is the risk of giving folate alone to a B12-deficient patient? The anaemia may improve while neurological complications of B12 deficiency remain untreated.

Question 46 (source Q118). A 25-year-old woman collapses with abdominal pain, shoulder-tip pain, hypotension and peritonism. What is the most urgent diagnosis to exclude?

Obstetrics & Gynaecology — Gynaecological emergencies and pelvic anatomy

Recorded recall sessions: September 2020

A. Uncomplicated ovarian cyst

B. Biliary colic

C. Ruptured ectopic pregnancy

D. Acute uncomplicated appendicitis

Answer and explanation

C. Ruptured ectopic pregnancy

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.

A. An uncomplicated cyst does not explain severe haemorrhagic shock and referred diaphragmatic pain.

B. Typically causes right upper quadrant pain without sudden haemorrhagic shock in a young woman.

D. Usually progresses with localised abdominal signs rather than abrupt intraperitoneal blood-loss shock.

A negative pregnancy history does not exclude pregnancy; obtain urgent hCG testing.
Bedside ultrasound may reveal free intraperitoneal fluid but should not delay life-saving surgery in an unstable patient.
RhD status and anti-D prophylaxis considerations follow local obstetric guidance.

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

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

Viva extension: What causes the shoulder-tip pain? Diaphragmatic irritation referred through the phrenic nerve (C3–C5).

Question 47 (source Q264). A 32-year-old woman has biopsy-confirmed invasive carcinoma of the uterine cervix. Which regional nodal basin is among the earliest and most important routes of lymphatic spread?

Obstetrics & Gynaecology — Gynaecological oncology and pelvic anatomy

Recorded recall sessions: January 2021

A. Internal iliac (hypogastric) nodes

B. Superficial inguinal nodes

C. Axillary nodes

D. Popliteal nodes

Answer and explanation

A. Internal iliac (hypogastric) nodes

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.

B. Primarily drain external genital skin and lower vaginal structures, not the uterine cervix.

C. Drain upper limb and much of breast/chest wall, not the pelvis.

D. Drain parts of the lower limb, not pelvic reproductive organs.

Cervical lymphatic spread can involve parametrial and pelvic nodes.
External iliac and obturator chains are also important regional sites.
Para-aortic disease generally represents more cephalad spread.
Staging and treatment use cross-sectional imaging and specialist oncology assessment.

Exam pearl: Cervix drains to pelvic iliac/obturator nodes, not superficial inguinal nodes.

Examiner trap: Lower vaginal and vulval tumours may drain to inguinal nodes; do not transfer that pattern to cervical cancer.

Viva extension: Name two additional regional groups: obturator and external iliac lymph nodes.

Question 48 (source Q308). A 55-year-old woman is diagnosed with epithelial ovarian carcinoma. Which nodal group is the principal first-echelon route of lymphatic spread from the ovary?

Obstetrics & Gynaecology — Gynaecological oncology and pelvic anatomy

Recorded recall sessions: January 2020; January 2021

A. Superficial inguinal nodes

B. Internal iliac nodes

C. Para-aortic (lumbar) nodes

D. Popliteal nodes

Answer and explanation

C. Para-aortic (lumbar) nodes

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.

A. These drain much of the superficial lower limb and external genital skin; they are not the principal ovarian drainage route.

B. These receive lymph from several pelvic organs but are not the primary route following the ovarian vessels.

D. Popliteal nodes drain distal lower-limb structures and have no normal direct ovarian drainage.

Ovarian lymphatic drainage differs from cervical drainage.
Ovarian tumours may also disseminate transcoelomically throughout the peritoneum.
Pelvic nodal involvement can occur but does not negate the principal para-aortic pathway.
Right and left ovarian drainage patterns may differ in detail.

Exam pearl: Ovary → para-aortic nodes; scrotal skin → superficial inguinal nodes.

Examiner trap: Do not confuse the ovary with the vulva or cervix when choosing regional nodes.

Viva extension: Why para-aortic nodes? The ovary develops in the posterior abdomen and descends, retaining its vascular and lymphatic route.

Question 49 (source Q617). A woman with biopsy-proven invasive carcinoma of the uterine cervix is being assessed for pelvic nodal spread. Which lymph-node group commonly receives lymphatic drainage from the cervix?

Obstetrics & Gynaecology — Gynaecological oncology and pelvic anatomy

Recorded recall sessions: January 2020

A. Superficial inguinal nodes

B. Internal iliac (hypogastric) nodes

C. Axillary nodes

D. Popliteal nodes

Answer and explanation

B. Internal iliac (hypogastric) nodes

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.

A. Superficial inguinal nodes primarily receive drainage from the lower vagina, vulva and superficial perineum.

C. Axillary nodes drain the breast and upper limb, not the cervix.

D. Popliteal nodes primarily drain lateral foot and posterolateral calf structures.

Pelvic regional nodes include obturator, internal and external iliac groups.
The uterine cervix is not primarily an inguinal-draining organ.
Para-aortic nodal disease may occur through higher-echelon spread.
Pelvic MRI assesses local tumour extent; nodal staging uses appropriate cross-sectional imaging.

Exam pearl: Internal iliac and obturator nodes are high-yield regional stations in cervical carcinoma.

Examiner trap: Do not confuse cervical cancer drainage with lower vaginal or vulval drainage to groin nodes.

Viva extension: Where can cervical carcinoma spread directly? Through parametrial tissues into adjacent pelvic structures; lymphatic dissemination occurs through regional pelvic chains.

Question 50 (source Q680). A woman develops numbness of the anterior labia majora after an open inguinal hernia repair. Which nerve most directly supplies this cutaneous region?

Obstetrics & Gynaecology — Gynaecological oncology and pelvic anatomy

Recorded recall sessions: January 2023; April 2026

A. Ilioinguinal nerve (L1)

B. Pudendal nerve (S2–S4)

C. Obturator nerve (L2–L4)

D. Femoral nerve (L2–L4)

Answer and explanation

A. Ilioinguinal nerve (L1)

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.

B. The pudendal nerve supplies much of the posterior vulva/perineum, not the principal anterior labial territory in this vignette.

C. The obturator nerve supplies medial-thigh skin and adductor muscles, not the anterior labia majora.

D. The femoral nerve supplies anterior-thigh sensation and quadriceps motor function, not anterior labial sensation.

Ilioinguinal nerve originates mainly from L1.
It traverses part of the inguinal canal but does not enter via the deep inguinal ring.
In women it supplies anterior labia majora and adjacent groin skin.
Posterior labial branches of the pudendal nerve supply the posterior labia.

Exam pearl: Anterior labia majora = ilioinguinal nerve; posterior labia = pudendal branches.

Examiner trap: The whole labia majora do not have a single exclusive nerve supply; specify anterior versus posterior.

Viva extension: Which other nerve can cause groin sensory disturbance after hernia surgery? The iliohypogastric and genital branch of genitofemoral nerves may also be involved.

Question 51 (source Q759). A 59-year-old woman has a biopsy-confirmed squamous carcinoma on the lateral labium majus. Examination identifies a firm ipsilateral groin node; pelvic imaging does not show a cervical mass. Which lymph-node group is the usual first regional drainage basin for this vulvar lesion?

Obstetrics & Gynaecology — Gynaecological oncology and pelvic anatomy

Recorded recall sessions: September 2024; January 2025

A. Para-aortic lymph nodes

B. Superficial inguinal lymph nodes

C. Internal iliac lymph nodes

D. Inferior mesenteric lymph nodes

Answer and explanation

B. Superficial inguinal lymph nodes

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.

A. Para-aortic nodes are not the usual first-echelon nodes for a lateral labial primary.

C. Internal iliac nodes are important in cervical cancer and later pelvic spread, but are not the typical first-echelon nodes for a lateral vulvar lesion.

D. Inferior mesenteric nodes drain hindgut territories, not the labia majora.

Vulvar and distal vaginal lymphatics commonly reach superficial inguinal nodes first.
Deep inguinofemoral nodes, including Cloquet node, lie on the subsequent pathway to pelvic nodes.
Near-midline vulvar tumours may require bilateral groin assessment.
Cervical carcinoma usually drains first to pelvic iliac and obturator groups rather than superficial inguinal nodes.

Exam pearl: Vulva → superficial inguinal nodes; cervix → pelvic iliac/obturator nodes.

Examiner trap: Postcoital bleeding alone suggests several gynaecological diagnoses; a definite labial lesion is needed before attributing inguinal nodes to vulvar cancer.

Viva extension: Why does a midline vulvar lesion require bilateral nodal consideration? Vulvar lymphatics communicate across the midline, allowing contralateral inguinofemoral drainage.

Question 52 (source Q883). During vaginal surgery near the anterior vaginal fornix at the level of the cervix, which urinary structure lies immediately anterior to the upper vaginal wall and is at risk of injury?

Obstetrics & Gynaecology — Gynaecological oncology and pelvic anatomy

Recorded recall sessions: September 2019

A. The bladder base

B. The rectum

C. The uterine fundus

D. The dome of the bladder

Answer and explanation

A. The bladder base

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.

B. The rectum lies posterior to the vagina, separated superiorly by the rectouterine pouch and connective tissue.

C. The fundus lies superior to the cervix rather than immediately anterior to the upper vaginal wall.

D. The dome is the superior mobile surface; the base is the portion most closely related to the anterior upper vagina/cervix.

The bladder is anterior to the uterus and upper vagina.
The ureter passes beneath the uterine artery near the cervix.
Bladder injury can lead to vesicovaginal fistula.
Pelvic surgical planes should be developed with awareness of the bladder reflection.

Exam pearl: Anterior to the upper vagina/cervix is the bladder base.

Examiner trap: Do not confuse the bladder dome with the base or the posterior rectal relation.

Viva extension: What is the classic ureter–uterine artery relation? The ureter passes under the uterine artery: water under the bridge.

Question 53 (source Q888). A woman has biopsy-confirmed cervical carcinoma. PET–CT identifies metastatic external iliac and obturator lymph nodes but no para-aortic nodes or distant metastases. Under the 2018 FIGO system, what nodal stage designation applies?

Obstetrics & Gynaecology — Gynaecological oncology and pelvic anatomy

Recorded recall sessions: May 2022

A. Stage IIIC2r

B. Stage IIIC1r

C. Stage IVB

D. Stage IA1

Answer and explanation

B. Stage IIIC1r

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.

A. IIIC2 is reserved for para-aortic nodal metastases, which are absent in the vignette.

C. IVB requires distant metastasis; pelvic regional nodes alone do not meet this criterion.

D. IA1 describes microscopic stromal invasion within strict limits and cannot describe established nodal metastasis.

Pelvic nodal groups include obturator, internal iliac and external iliac nodes.
FIGO IIIC1 = pelvic nodes; IIIC2 = para-aortic nodes.
The suffix r denotes imaging-based nodal staging.
The suffix p denotes pathological nodal staging.

Exam pearl: Cervical cancer pelvic-node metastases are FIGO IIIC1; para-aortic nodes are IIIC2.

Examiner trap: Do not classify pelvic regional nodes as distant stage IVB disease.

Viva extension: What changes the suffix from r to p? Histological confirmation of the nodal metastasis.

Question 54 (source Q970). A 61-year-old woman has biopsy-confirmed squamous carcinoma confined to the distal third of the vagina. There is no vulval or cervical primary. Which regional lymph node group is particularly important to assess because of the primary tumour location?

Obstetrics & Gynaecology — Gynaecological oncology and pelvic anatomy

Recorded recall sessions: January 2023

A. Inguinal-femoral lymph nodes

B. Only para-aortic lymph nodes

C. Only internal iliac nodes

D. Only mediastinal lymph nodes

Answer and explanation

A. Inguinal-femoral lymph nodes

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.

B. Para-aortic nodes are not the primary regional drainage of an isolated distal vaginal lesion.

C. Upper vaginal lesions predominantly drain to pelvic nodes; distal lesions drain toward the groin, although networks overlap.

D. These are distant, not regional, lymph nodes for a distal vaginal carcinoma.

Lower third vagina → inguinal-femoral nodes.
Upper vagina → internal/external iliac and obturator nodes.
Mid-vaginal lymphatic drainage may be bidirectional.
Exclude cervical and vulval extension before classifying a primary vaginal carcinoma.

Exam pearl: Distal vagina follows vulval groin-node drainage; upper vagina follows pelvic-node drainage.

Examiner trap: Bilateral inguinal nodes alone do not identify a primary lesion; the source lacked an examination or biopsy.

Viva extension: Which nodes primarily drain the upper vagina? Internal iliac, external iliac and obturator pelvic nodes.

Question 55 (source Q992). A 6-year-old child weighing 20 kg is prescribed oral paracetamol at 15 mg/kg per dose, with a maximum of four doses in 24 hours. The child has normal liver function and is taking no other paracetamol-containing medicine. What total amount corresponds to four such doses?

Perioperative & Critical Care — Perioperative pharmacology and dosing

Recorded recall sessions: April 2026

A. 300 mg

B. 600 mg

C. 1,200 mg

D. 2,400 mg

Answer and explanation

C. 1,200 mg

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.

A. 300 mg is the amount in one dose, not four.

B. 600 mg is two 300-mg doses, not four.

D. 2,400 mg would be 120 mg/kg/day, double the stated four-dose regimen.

Weight-based dose: 15 mg/kg × 20 kg = 300 mg.
Four 300-mg doses total 1,200 mg = 60 mg/kg/day.
Check the preparation concentration before converting milligrams to millilitres.
Neonatal, IV, hepatic impairment and other formularies may have different maxima; always use current local prescribing guidance.

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

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

Viva extension: How much volume is one 300-mg dose using 120 mg/5 mL suspension? 12.5 mL; confirm the actual product strength and age-specific formulary.

Question 56 (source Q205). Minutes after intravenous co-amoxiclav, a 21-year-old surgical patient develops wheeze, widespread urticaria and blood pressure 60/40 mmHg. What is the immediate first-line drug and route for an adult with anaphylaxis?

Perioperative & Critical Care — Perioperative physiology and emergencies

Recorded recall sessions: January 2019; May 2022

A. Hydrocortisone 100 mg IV

B. Adrenaline 500 micrograms IM into the anterolateral thigh

C. Chlorphenamine 10 mg IV

D. Adrenaline 1 mg IV bolus

Answer and explanation

B. Adrenaline 500 micrograms IM into the anterolateral thigh

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.

A. Steroids do not rapidly reverse airway oedema or shock and are not first-line.

C. Antihistamines may relieve cutaneous symptoms but do not treat cardiovascular collapse.

D. A 1-mg IV bolus is a cardiac-arrest dose and can be dangerous in a patient with a pulse; IV infusion requires specialist monitoring for refractory anaphylaxis.

Stop the triggering infusion and summon resuscitation assistance.
Repeat IM adrenaline after 5 minutes if life-threatening features persist.
Titrate IV crystalloid for shock while reassessing airway and breathing.
Record the reaction and arrange allergy evaluation after stabilisation.

Exam pearl: Adult anaphylaxis: adrenaline 0.5 mg IM, 1:1000, lateral thigh.

Examiner trap: Do not confuse IM 1:1000 adrenaline with IV 1:10,000 cardiac-arrest dosing.

Viva extension: When is an IV adrenaline infusion considered? Refractory anaphylaxis under experienced critical-care supervision.

Question 57 (source Q304). Eight weeks after an uncomplicated elective laparotomy, a patient has a flat, closed, non-inflamed scar. Which histological process predominates in the maturing wound?

Perioperative & Critical Care — Perioperative physiology and emergencies

Recorded recall sessions: September 2021

A. Active platelet aggregation and clot formation

B. Neutrophil margination and acute inflammation

C. Reduction in capillary density with collagen remodelling

D. Rapid new capillary sprouting as the dominant process

Answer and explanation

C. Reduction in capillary density with collagen remodelling

During the remodelling phase, type III collagen is replaced and reorganised toward stronger type I collagen; excessive newly formed vessels regress, so mature scar tissue becomes less vascular and paler.

A. Haemostasis is an immediate post-injury event, not the dominant process in a two-month-old closed scar.

B. Neutrophil influx predominates early in the inflammatory phase, usually within the first days.

D. Angiogenesis is prominent during proliferative granulation tissue formation; vascularity subsequently regresses.

Remodelling begins after the proliferative phase and may continue for months.
Tensile strength increases but rarely returns to that of uninjured skin.
Myofibroblasts drive wound contraction.
Excess collagen deposition can produce hypertrophic scars or keloids.

Exam pearl: A two-month-old scar is mainly remodelling, not clotting or acute inflammation.

Examiner trap: A scar becoming pale reflects vascular regression, not impaired perfusion requiring treatment.

Viva extension: Which collagen is laid down early? Type III; later remodelling increases type I collagen.

Question 58 (source Q635). A patient scheduled for elective bowel resection asks which outcome should NOT be promised as a proven routine consequence of an enhanced recovery after surgery (ERAS) pathway. Which response is most appropriate?

Perioperative & Critical Care — Perioperative physiology and emergencies

Recorded recall sessions: January 2021

A. Earlier mobilisation

B. Reduced average hospital stay

C. Lower perioperative physiological stress

D. Guaranteed prevention of chronic postsurgical pain

Answer and explanation

D. Guaranteed prevention of chronic postsurgical pain

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.

A. Early mobilisation is a core component of ERAS, so it is an expected programme element.

B. Many ERAS programmes reduce average hospital length of stay.

C. Multimodal optimisation can attenuate stress responses after surgery.

ERAS pathways include preoperative counselling, opioid-sparing analgesia and early mobilisation.
Early oral intake and avoiding unnecessary tubes are common components.
Clinical outcomes depend on patient, operation and adherence to the pathway.
Chronic postsurgical pain can still occur despite ERAS compliance.

Exam pearl: ERAS supports faster recovery but cannot guarantee absence of chronic pain.

Examiner trap: Beware absolute statements such as guaranteed prevention of chronic pain.

Viva extension: Name four ERAS elements: education, multimodal analgesia, early mobilisation and early appropriate enteral intake.

Question 59 (source Q639). A hospitalised adult with suspected infection is assessed using qSOFA. Which finding contributes one point to the score?

Perioperative & Critical Care — Perioperative physiology and emergencies

Recorded recall sessions: May 2023; September 2024

A. New altered mental status

B. Systolic blood pressure of 110 mmHg

C. Normal alert mental status

D. Respiratory rate of 18/min

Answer and explanation

A. New altered mental status

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.

B. A systolic pressure of 110 mmHg is above the threshold of 100 mmHg.

C. Normal alert mental status scores zero for the mental-status component.

D. A rate of 18/min is below the qSOFA respiratory threshold of 22/min.

qSOFA criteria: RR ≥22/min, SBP ≤100 mmHg, altered mentation.
A score ≥2 indicates higher risk of poor outcomes in suspected infection.
Sepsis is life-threatening organ dysfunction from a dysregulated host response to infection.
Use clinical judgement and appropriate early-warning tools; a low qSOFA score does not exclude sepsis.

Exam pearl: qSOFA = 22, 100, altered mentation.

Examiner trap: The systolic threshold is ≤100 mmHg, not <90 mmHg; qSOFA is not the definition of sepsis.

Viva extension: What does SOFA quantify? Organ dysfunction across respiratory, coagulation, liver, cardiovascular, CNS and renal systems.

Question 60 (source Q956). A 38-year-old adult is undergoing elective hand surgery with a pneumatic upper-arm tourniquet. Systolic blood pressure is 130 mmHg and limb occlusion pressure has not been measured. Which planned inflation pressure is within the British Orthopaedic Association recommended adult upper-limb range?

Perioperative & Critical Care — Perioperative physiology and emergencies

Recorded recall sessions: April 2026

A. 200 mmHg

B. 130 mmHg

C. 300 mmHg

D. 400 mmHg

Answer and explanation

A. 200 mmHg

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.

B. A pressure equal to systolic BP does not provide the recommended safety margin for arterial occlusion.

C. 300 mmHg exceeds the recommended SBP-based range in this scenario and unnecessarily increases compression risk.

D. 400 mmHg is excessive for this adult upper-limb scenario.

BOASt adult upper limb: SBP + 50–100 mmHg.
BOASt adult lower limb: SBP + 70–130 mmHg.
Use a correctly sized cuff and protect skin from preparation fluid.
Aim for ischaemic time below 120 minutes; extensions require documented risk–benefit assessment.

Exam pearl: For an adult upper limb, use SBP plus 50–100 mmHg under the BOASt SBP-based approach.

Examiner trap: A fixed 250–300 mmHg is not automatically appropriate for every patient; cuff fit and local policy matter.

Viva extension: What should the operative record document? Cuff details, skin protection, pressure, inflation and deflation times, and site condition.

Question 61 (source Q991). A 67-year-old patient is stable after laparoscopic colectomy. In the recovery room his core temperature is 35.7°C, oxygenation is normal and pain is controlled. According to NICE perioperative hypothermia guidance, which action is most appropriate before transfer to the ward?

Perioperative & Critical Care — Perioperative physiology and emergencies

Recorded recall sessions: April 2026

A. Continue active forced-air warming and defer ward transfer until the temperature is at least 36.0°C.

B. Transfer immediately because 35.5°C is the accepted threshold.

C. Give a prophylactic antibiotic solely for the low temperature.

D. Administer intravenous paracetamol to raise core temperature.

Answer and explanation

A. Continue active forced-air warming and defer ward transfer until the temperature is at least 36.0°C.

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.

B. 35.5°C is below the recommended transfer threshold and still constitutes hypothermia.

C. Hypothermia alone does not establish infection and is not an indication for prophylactic antibiotics.

D. Paracetamol is an antipyretic and analgesic, not a rewarming intervention.

NICE threshold for ward transfer: core temperature ≥36.0°C.
Measure temperature on arrival in recovery and every 15 minutes.
Forced-air warming is recommended when temperature is below 36.0°C.
Hypothermia can increase shivering, coagulopathy and wound complications.

Exam pearl: NICE recovery-room ward-transfer temperature is at least 36.0°C.

Examiner trap: Do not confuse the minimum safe transfer threshold with normal thermoregulation around 36.5–37.5°C.

Viva extension: What if the temperature falls below 36.0°C on the ward? Use active forced-air warming and monitor temperature at least every 30 minutes during warming.

Question 62 (source Q29). Five days after laparotomy, a patient's incision produces a sudden serosanguinous discharge followed by separation of deep wound layers. What complication is most likely?

Perioperative & Critical Care — Postoperative complications and wound care

Recorded recall sessions: April 2021

A. Simple superficial wound cellulitis

B. Uncomplicated seroma

C. Abdominal wound dehiscence (burst abdomen)

D. Keloid formation

Answer and explanation

C. Abdominal wound dehiscence (burst abdomen)

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.

A. Causes erythema and tenderness without characteristic fascial separation.

B. Typically causes clear fluid but not deep fascial disruption.

D. Develops later as excessive scar tissue, not an acute postoperative mechanical failure.

Risk factors include infection, malnutrition, coughing and raised intra-abdominal pressure
Cover exposed bowel with sterile saline-moistened dressings
Urgently resuscitate and obtain surgical management.

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

Examiner trap: Do not mistake deep dehiscence for a harmless superficial seroma.

Viva extension: What layer is critical for abdominal wound strength? Fascial aponeurosis.

Question 63 (source Q75). A patient with non-small-cell lung cancer is treated with an antibody blocking PD-1 on T lymphocytes. Which treatment class is this?

Oncology — Cancer immunotherapy and palliation

Recorded recall sessions: January 2025

A. Immune checkpoint inhibitor therapy

B. mTOR inhibition

C. VEGF-targeted antiangiogenic therapy

D. Conventional cytotoxic alkylating chemotherapy

Answer and explanation

A. Immune checkpoint inhibitor 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.

B. Blocks intracellular growth signalling and does not target PD-1.

C. Targets vascular growth pathways rather than T-cell checkpoints.

D. Directly damages proliferating cells and is mechanistically distinct from PD-1 blockade.

Examples include pembrolizumab and nivolumab
Immune-related colitis, pneumonitis and endocrinopathies may occur
PD-L1 expression is relevant in selected indications.

Exam pearl: PD-1 blockade = immunotherapy, not conventional chemotherapy.

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

Viva extension: What is CTLA-4? Another T-cell inhibitory checkpoint targeted by ipilimumab.

Question 64 (source Q48). A patient with primary osteosarcoma develops metastatic disease. Which organ is most commonly affected?

Oncology — Cancer metastasis and staging

Recorded recall sessions: September 2022

A. Lung

B. Brain

C. Kidney

D. Liver

Answer and explanation

A. Lung

Osteosarcoma commonly disseminates haematogenously, with the lung as its principal metastatic destination. Chest CT is important for staging and surveillance.

B. Less common as the first site of osteosarcoma spread.

C. Not a typical dominant metastatic target.

D. Can be involved but is less frequent than pulmonary metastasis.

A typical primary site is the metaphysis around the knee
Biopsy should be planned by a specialist sarcoma team
Treatment generally combines systemic chemotherapy and oncological resection.

Exam pearl: Osteosarcoma metastasises most commonly to lung.

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

Viva extension: What microscopic feature defines osteosarcoma? Malignant osteoid formed directly by tumour cells.

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MRCS Part A — Common Surgical Conditions: Sections 10–15

MRCS Part A — Common Surgical Conditions: Sections 10–15

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MRCS Part A — Common Surgical Conditions: Sections 10–15

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