PA25.3 | Obstructive Airway Disease & Bronchiectasis — Summary & Reflection

REFLECT

Before reading further, close your eyes and mentally walk through this scenario: A 55-year-old woman presents with 2 years of recurrent haemoptysis, foul-smelling sputum, and digital clubbing. Her chest X-ray shows 'tram-track' shadows and ring shadows in the left lower lobe. She gives a history of pulmonary TB 15 years ago.

Without looking back:
1. What is the most likely diagnosis?
2. Name the 'tram-track' and 'ring shadow' signs on plain X-ray.
3. Which complication (haemoptysis, amyloidosis, cor pulmonale, brain abscess) is already present?
4. What is the pathogenic cycle that led here from her TB?

KEY TAKEAWAYS

Core take-home points:

• Obstructive pattern: FEV1/FVC <0.70; obstructive diseases include COPD (emphysema + chronic bronchitis), asthma, bronchiectasis.

• Emphysema: Permanent airspace enlargement + wall destruction (no fibrosis). Four types: centriacinar (smoking, upper lobe), panacinar (alpha1-AT deficiency, lower lobe), paraseptal (pneumothorax risk), irregular (scars). Pink puffer phenotype.

• COPD pathogenesis: Protease-antiprotease imbalance (elastase vs alpha1-AT) + oxidant damage, both from smoking.

• Chronic bronchitis: Clinical definition (productive cough >=3 mo/2 yr). Reid index >0.5. Blue bloater phenotype. Cor pulmonale early.

• Asthma: Episodic, reversible. Atopic (Type I hypersensitivity, IgE) vs non-atopic. Morphology: Curschmann spirals, Charcot-Leyden crystals, eosinophils, basement membrane thickening.

• Bronchiectasis: Permanent bronchial dilatation. Causes: TB/infection (India), CF, Kartagener, ABPA, obstruction. Obstruction-infection cycle. Complications: haemoptysis, cor pulmonale, amyloidosis, brain abscess.

• COPD complications: Cor pulmonale, respiratory failure (Type I in emphysema, Type II in bronchitis), spontaneous pneumothorax (paraseptal).