Pathophysiology
Clinical meaning
Chronic Obstructive Pulmonary Disease encompasses chronic bronchitis (excessive mucus production with productive cough for ≥ 3 months in 2 consecutive years) and emphysema (destruction of alveolar walls leading to air trapping). Chronic inflammation driven primarily by cigarette smoke causes goblet cell hyperplasia, smooth muscle hypertrophy, and loss of elastic recoil. Over time, patients develop a hypoxic drive where low oxygen (rather than high CO2) triggers breathing.