Introduction for COPD

COPD is a progressive condition characterized by chronic airflow limitation that is not fully reversible. The term COPD refers primarily to the entities of emphysema and chronic bronchitis. Emphysema is defined pathologically as nonuniform enlargement of the distal airspaces with destruction of the acini, loss of lung elasticity, and absence of any fibrotic changes. Chronic bronchitis is defined clinically as cough productive of at least 2 tbsp of sputum on most days of 3 consecutive mos in 2 consecutive yrs, in the absence of other lung diseases. Although asthma, cystic fibrosis, bronchiectasis, bronchiolitis, and sarcoidosis are associated with expiratory airflow obstruction, they do not fall within the classification of COPD. The diagnosis should be considered in any patient with cough, sputum production, and/or dyspnea, and a history of exposure to risk factors for COPD. Classically, chronic bronchitis accounts for 85% of COPD cases, with the remaining 15% of COPD patients having emphysema. Some patients with COPD exhibit manifestations of both emphysema and chronic bronchitis. The chronic progression of expiratory airflow obstruction is punctuated by episodic worsening in the cough, dyspnea, and sputum production that characterize the condition. These episodes are known as acute exacerbations of COPD.