Bronchiectasis

Permanent Dilation & Necrotizing Infection

FreeMedSite USMLE STEP 1 REVIEW

Interactive Study:

Definition

Chronic necrotizing infection of bronchi → permanent dilation of airways.

Associations

Congenital/Genetic

• • Cystic Fibrosis (Most common in US)
• • Kartagener Syndrome (Dynein arm defect)
• • Primary Ciliary Dyskinesia (Impaired motility)

Acquired

• • Obstruction (Tumor, Foreign Body)
• • Post-infectious (TB, Pertussis)
• • ABPA (Aspergillus fumigatus)

Presentation

• • Purulent sputum (Daily/Foul-smelling)
• • Hemoptysis (due to bronchial artery hypertrophy)
• • Digital clubbing
• • Recurrent infections (Pseudomonas)

Diagnosis

Gold Standard HRCT Chest

Classic CT Finding Signet-ring sign

CXR Finding Tram-track opacities

Complications

Pulmonary Hypertension → Cor pulmonale. Secondary Amyloidosis (AA type) due to chronic inflammation. Risk of Brain abscess due to hematogenous spread.

1. What is the "signet-ring sign" seen on HRCT?

Answer: Dilation of the bronchus such that its diameter is larger than the adjacent pulmonary artery.

2. Which pathogen is most commonly associated with bronchiectasis in Cystic Fibrosis?

Answer: Pseudomonas aeruginosa.

3. What triad defines Kartagener Syndrome?

Answer: Bronchiectasis + Situs Inversus + Chronic Sinusitis (and infertility).

4. Why does amyloidosis occur in these patients?

Answer: Chronic inflammation leads to increased Serum Amyloid A (SAA), causing AA amyloid deposits.

5. What classic CXR finding is associated with airway wall thickening?

Answer: Tram-track opacities (parallel linear opacities).

6. What is the classic sputum description in Bronchiectasis?

Answer: Copious, purulent, and often foul-smelling (fetid) sputum that may separate into layers.

7. Which allergic condition is a known cause of localized bronchiectasis?

Answer: Allergic Bronchopulmonary Aspergillosis (ABPA).

8. What PFT pattern is typically seen in advanced Bronchiectasis?

Answer: An obstructive pattern (decreased FEV1/FVC ratio).

9. What is the fundamental defect in Primary Ciliary Dyskinesia?

Answer: Defect in the dynein arms of the cilia, leading to poor ciliary motility.

10. Name a common cause of massive hemoptysis in these patients.

Answer: Erosion/rupture of hypertrophied bronchial arteries.

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1. Definition

Permanent dilation of bronchi due to chronic necrotizing infection or obstruction, leading to recurrent infections and impaired airway clearance.

2. Classification / Types

• 1. Cylindrical (Tubular): Uniform dilation, mildest form.
• 2. Varicose: Irregular, beaded appearance.
• 3. Cystic (Saccular): Ballooned, cyst-like ends, severe disease.

3. Etiology / Associated Conditions

A. Post-infectious

• Severe pneumonia, TB, pertussis

B. Obstructive

• Tumors, foreign bodies, enlarged lymph nodes

C. Genetic / Congenital

• Cystic Fibrosis (CF) – thick mucus → impaired clearance

• Kartagener Syndrome – poor ciliary motility, sinusitis, situs inversus

D. Immune deficiency

• Hypogammaglobulinemia, other immunodeficiencies

E. Allergic / Inflammatory

• Allergic Bronchopulmonary Aspergillosis (ABPA) – mucus plugging, localized bronchiectasis

F. Environmental / Acquired

• Tobacco smoking, chronic inhalation injuries

4. Pathophysiology

• • Cycle of infection → inflammation → airway damage → further infection
• • Destruction of bronchial muscular and elastic components
• • Impaired mucociliary clearance → mucus accumulation → chronic infection

5. Clinical Features

• • Cough with daily purulent sputum
• • Recurrent respiratory infections (most often Pseudomonas aeruginosa)
• • Hemoptysis – mild to massive
• • Digital clubbing
• • Dyspnea, wheezing, fatigue, weight loss in advanced disease

6. Investigations

A. Imaging

High-Resolution CT (HRCT): Gold Standard. Signet-ring sign (bronchus > artery); mucus plugging.

Chest X-ray: May show tram-track opacities, but less sensitive.

B. Microbiology

Sputum culture: Identify pathogens (Pseudomonas, Haemophilus, Staph aureus).

C. Pulmonary Function Tests (PFTs)

Obstructive pattern: ↓ FEV₁/FVC ratio.

7. Management

• • Airway Clearance (PT, drainage, oscillatory devices)
• • Antibiotics (Acute exacerbations & Chronic colonization)
• • Bronchodilators (for obstructive symptoms)
• • Surgery (Localized disease or life-threatening hemoptysis)
• • Treat Underlying Cause (CF, ABPA, immune therapy)

8. Complications / Other

• • Respiratory failure
• • Pulmonary hypertension / Cor pulmonale
• • Amyloidosis (rare)
• • Massive hemoptysis

💡 High-Yield Pearls

Daily purulent sputum + recurrent infections + digital clubbing → classic bronchiectasis.
Most common pathogen in advanced disease: Pseudomonas aeruginosa.
Kartagener Syndrome triad: Bronchiectasis + sinusitis + situs inversus.
HRCT chest is the diagnostic gold standard.