Chronic Obstructive Pulmonary Disease IV: Clinical Manifestations

COPD comprises chronic bronchitis and emphysema, which often co-occur but differ in dominant symptoms. Chronic bronchitis features persistent productive cough and airway inflammation, while emphysema involves destruction of alveolar walls and air trapping. Most patients exhibit features of both conditions, combining mucus production with airflow limitation and hyperinflation.

Chronic bronchitis causes persistent airway inflammation, enlarged mucus glands, and goblet cell hyperactivity, producing thick, sometimes purulent mucus. This mucus buildup narrows airways, creating wheezing and rhonchi. Over time, dyspnea develops, progressing from exertion-related difficulty to breathlessness at rest. These changes significantly impair gas exchange.

Emphysema destroys alveolar walls, causing air trapping, reduced elasticity, and lung hyperinflation. This results in a barrel-shaped chest and flattened diaphragm, both reducing breathing efficiency. Patients appear thin and tachypneic, often using accessory muscles and pursed-lip breathing to ease exhalation.

Chronic hypoxemia leads to cyanosis, a bluish discoloration of the skin, and stimulates erythropoietin release, causing secondary polycythemia or excess red blood cell production. Pulmonary hypertension may develop and progress to cor pulmonale, presenting with leg swelling, fatigue, and venous congestion.

Chronic bronchitis presents with persistent productive cough and thick mucus due to airway inflammation and goblet cell hyperactivity. Emphysema, by contrast, is characterized by progressive breathlessness with minimal or no sputum production, despite severe airflow obstruction from alveolar wall destruction.

Pursed-lip breathing and accessory muscle use are compensatory strategies to ease exhalation and improve ventilation. In emphysema, lung hyperinflation and diaphragm flattening reduce normal breathing efficiency. These techniques help patients maintain adequate gas exchange and reduce the work of breathing during physical activity.

In chronic bronchitis, cyanosis appears relatively early due to chronic hypoxemia from persistent airway obstruction and mucus buildup. In emphysema, gas exchange remains relatively preserved early in disease progression, so cyanosis appears later as alveolar destruction advances and hypoxemia worsens.