Alterations in lung defense and unusual infections in chronic bronchitis.

Cigarette smoking is the primary irritant responsible for the syndrome of chronic bronchitis. In addition to the symptoms of cough and sputum production, smoking leads to structural changes and immunologic alterations that place the patient with chronic bronchitis at increased risk for tracheobronchial infections. This article reviews the modifications in lung defenses that occur as a result of chronic bronchitis. The uncommon infectious agents that are seen in chronic bronchitis are also discussed including clinical presentation, diagnosis, and treatment.