COPD

Chronic obstructive pulmonary disease (COPD) is a heterogeneous lung condition with persistent respiratory symptoms caused by abnormalities of the airways, alveoli, or both. Tobacco smoke is a major exposure, but occupational dusts and fumes, indoor or outdoor air pollution, impaired lung development, previous respiratory illness, and alpha-1 antitrypsin deficiency can also contribute. Ask about the whole exposure and family history instead of treating smoking as a required cause. Damage is not fully reversible, but treatment and exposure reduction can improve symptoms, function, and future risk. Emphysema is destruction of gas-exchanging alveolar surfaces. Loss of alveolar attachments and elastic recoil allows small airways to narrow during expiration. Air empties slowly, gas becomes trapped, and hyperinflation places the diaphragm at a mechanical disadvantage. Less surface area and uneven ventilation-perfusion matching impair gas exchange. A person may therefore have prolonged expiration, reduced breath sounds, exertional dyspnea, and limited reserve even when little sputum is present. Chronic bronchitis is the airway-predominant pattern: chronic irritation increases goblet cells and submucosal glands, mucus obstructs conducting airways, and mucociliary clearance is impaired. Its classic clinical description is...