Surgery in emphysema and asthma.

Emphysema and asthma are two chronic lung diseases which are often together associated with chronic bronchitis. The interrelationship of these three conditions is complex and poorly understood, but there is a great surge of interest in this field which presents a vast clinical problem in an ageing population. Asthma is due to transient narrowing of large air tubes caused by acute mucosal swelling with or without associated spasm of the bronchial musculature and is initiated by allergic or psychogenic stimuli. The essential lesion in chronic bronchitis seems likely to be a hypersecretion of mucus from large and small air tubes, there is interference with normal bronchial ciliary action and infection develops as a secondary manifestation. Chronic bronchitis and asthma are diseases of bronchi and in both there is, at times, acute or chronic bronchial obstruction which is incomplete. Emphysema, on the other hand, is a disease of distal lung tissue; its cause is not known, but it seems certain that it is very intimately related to partial bronchial obstruction.