Emphysema Pathophysiology: Alveolar Destruction and Systemic Consequences

Emphysema's hallmark is irreversible alveolar wall destruction, triggering a cascade of functional impairments:

Structural and Functional Sequelae

• Reduced gas exchange surface: Fewer, larger air spaces → diffusion impairment → hypoxemia.
• Loss of elastic recoil: Impaired passive expiration → air trapping → hyperinflation → flattened diaphragm → mechanical disadvantage.
• Dynamic hyperinflation: Incomplete exhalation during exercise ↑ end-expiratory lung volume → dyspnea.
• Pulmonary hypertension: Hypoxic vasoconstriction + capillary bed destruction → right ventricular afterload ↑ → cor pulmonale.
• Systemic effects: Hypoxia → polycythemia, cognitive impairment, fatigue; inflammation → cachexia, muscle wasting.

Clinical Correlation

Centriacinar (smoking-related) vs. panacinar (AATD) patterns differ in distribution but share final pathway. Severity correlates with FEV₁ decline, dyspnea scores (mMRC), and exacerbation frequency.

Therapeutic Targets

Bronchodilators reduce dynamic hyperinflation. Oxygen relieves hypoxic vasoconstriction. Pulmonary rehab improves mechanics and conditioning. No therapy regenerates alveoli—prevention remains key.