Chronic Obstructive Pulmonary Disease

Chronic obstructive pulmonary disease (COPD) is not a disease entity but a complex of conditions that contribute to airflow limitation. COPD is a chronic, slowly progressive disorder characterized by stable phases increasingly interrupted by worsening of symptoms, termed acute exacerbations. In 1995 the American Thoracic Society defined COPD as a disease state characterized by airflow obstruction resulting from chronic bronchitis or emphysema (Figure 27-1). Asthma is discussed separately because of its unique characteristics of inflammation and degree of reversibility. Most persons with COPD have one predominant disease entity, but often with manifestations of both. Why some individuals develop bronchitis and others develop emphysema is unknown. Hereditary or environmental factors or factors in the patient’s history are believed to influence differences in susceptibility and the predominant type of disease.