How does chronic bronchitis differ from emphysema in terms of their definitions and symptoms according to the chapter?

Chronic bronchitis is characterized by chronic inflammation of the bronchi, excessive mucus production, and a persistent cough with sputum for at least three months over two consecutive years. Emphysema involves permanent enlargement of the air spaces in the lungs with destruction of alveolar walls, leading to severe dyspnea and a mild nonproductive cough. Symptoms of chronic bronchitis include cough and sputum, while emphysema is marked by severe dyspnea and a lack of significant cough.

Chronic bronchitis and emphysema are both forms of chronic obstructive pulmonary disease (COPD) but differ in their definitions and symptoms. Chronic bronchitis is defined by chronic inflammation of the bronchi, resulting in excessive mucus production and a persistent cough with sputum lasting at least three months for two consecutive years. Patients typically present with a productive cough, copious sputum, and may be overweight and cyanotic. In contrast, emphysema is characterized by the permanent enlargement of air spaces in the lungs due to the destruction of alveolar walls, leading to severe dyspnea and a mild, often nonproductive cough. Patients with emphysema are usually thin, have a barrel-chested appearance, and experience significant difficulty in breathing, particularly during exertion.