centriacinar emphysema
Summary
Form of emphysema affecting the central/proximal acinus (respiratory bronchioles) with sparing of distal alveoli, predominantly in the upper lobes. Strongly associated with cigarette smoking.
Detail
Centriacinar (centrilobular) emphysema is caused by smoke-induced recruitment of neutrophils and macrophages that release elastase and oxidants, overwhelming antiproteases and destroying alveolar walls of respiratory bronchioles. The upper-lobe predominance reflects greater V/Q and particle deposition there. Contrast with panacinar emphysema (uniform involvement of the entire acinus, lower-lobe predominant) seen in alpha-1 antitrypsin deficiency (PiZZ), and with paraseptal emphysema, which involves distal acini and predisposes to spontaneous pneumothorax in tall young males. Clinically: barrel chest, decreased breath sounds, prolonged expiration, hyperinflation on CXR, and obstructive PFTs (low FEV1/FVC, increased TLC, decreased DLCO). 'Pink puffer' presentation.
Sources
- First Aid for USMLE Step 1 2024
- Robbins Basic Pathology 10th ed
- Pathoma
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