Clinical meaning
Cigarette smoke activates neutrophils/macrophages, releasing proteases (elastase) that destroy alveolar walls (Emphysema). Chronic Bronchitis involves goblet cell hyperplasia and mucus plugging. V/Q mismatch leads to hypoxemia and hypercapnia.
Diagnosis & workup
Diagnostics & workup: - Order ABG to assess respiratory acidosis and oxygenation status - Order CXR to rule out pneumonia, pneumothorax, or pleural effusion - Order CBC with differential (leukocytosis suggests infection) - Order BNP to differentiate from heart failure exacerbation - Order sputum culture and sensitivity if purulent sputum - Order procalcitonin to guide antibiotic therapy - Order spirometry (FEV1/FVC) when stable to assess severity - Order alpha-1 antitrypsin level if age < 45 or non-smoker
Risk factors: - Smoking history > 20 pack-years - Previous exacerbation requiring hospitalization - FEV1 < 50% predicted - Frequent exacerbations (≥ 2/year) - Cor pulmonale - Long-term oxygen therapy dependence - Concurrent cardiac disease - Alpha-1 antitrypsin deficiency