Pulmonology · USMLE Step 1 and Step 2

Bronchiectasis song

Bronchiectasis - Causes & Management, as a song. Hear the short teaser here. The full song is on YouTube and Spotify.

Bronchiectasis

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Key points in this song10

Bronchiectasis is defined as permanent, abnormal dilation of the bronchi due to destruction of the bronchial wall's muscular and elastic components.
The most common cause in the US is recurrent or severe pulmonary infections, particularly following childhood infections like measles or pertussis; cystic fibrosis is the leading identifiable genetic cause.
Classic presentation includes chronic productive cough with copious, purulent, foul-smelling sputum, hemoptysis, and digital clubbing.
High-resolution CT (HRCT) of the chest is the gold standard for diagnosis, showing the pathognomonic "tram-track sign" (parallel lines) and signet ring sign (bronchial diameter greater than adjacent pulmonary artery).
Cystic fibrosis causes bronchiectasis via CFTR dysfunction → thick mucus → chronic Pseudomonas aeruginosa and Staphylococcus aureus infections → progressive airway destruction.
Primary ciliary dyskinesia (Kartagener syndrome) presents with the triad of bronchiectasis, situs inversus, and sinusitis due to dynein arm defects impairing mucociliary clearance.
Allergic bronchopulmonary aspergillosis (ABPA) causes central bronchiectasis and should be suspected in asthmatic patients with elevated total IgE and positive Aspergillus precipitins.
Hypogammaglobulinemia (e.g., common variable immunodeficiency, X-linked agammaglobulinemia) predisposes to recurrent sinopulmonary infections and subsequent bronchiectasis.
Pulmonary function testing typically shows an obstructive pattern; FEV1/FVC ratio is reduced, reflecting airflow obstruction from damaged, dilated airways.
Management focuses on airway clearance techniques, treatment of acute exacerbations with antibiotics targeting Pseudomonas, and addressing the underlying cause (e.g., IVIG for immunodeficiency, antifungals for ABPA).