Exacerbations of chronic obstructive pulmonary disease: definition, aetiology and management.

(COPD) is preventable and treatable. It is characterised by airflow limitation which is not fully reversible and is progressive. The pathophysiological basis is an abnormal inflammatory response by the lung to inhaled noxious particles or gases, particularly cigarette smoke.1 In the developing world exposure to indoor air pollution, such as fumes from biomass fuels for cooking and heating, is a major cause of COPD.