Bronchiectasis

The traditional surgical maxim for infection is drainage. If the pus has somewhere to go, then it won't stay to cause trouble. The products of bronchial infection should not accumulate at foci in a model normal bronchial tree, where coughing and ciliary action will help to eliminate them. Oversimplifying, bronchiectasis is found in children and gets worse in adults. Pathologists believe that bronchial infection in the immature lung will cause non-uniformities that increase the risk from subsequent infections with accumulated damage. The definition of bronchiectasis implies that it is focal dilatation. We cannot suppose that the first infection is uniform and this statistical view of the universe allows us to presume small variations in damage to the lungs that are magnified by their effect on the developing lung and the predeliction of subsequent infections for areas that are different from the rest of the lung. Life is like that, the donkey will not starve if placed precisely between two carrots. Minor variations will occur and can be amplified by pathological processes. For example, the CT scans of normal patients can show areas of air-trapping, implying that ventilation is not uniform over the lung.

Congenital abnormalities of the bronchi, such as focal stenoses, dilatations, bronchial cysts or abnormal cilia will similarly predispose to infection in a given region. Smokers or smoking parents contribute to this risk since movement of the cilia of the bronchial mucosa is impaired by cigarette smoke.