Bronchiectasis

Bronchiectasis is abnormal chronic dilatation of one or more bronchi due to loss of structural elements in the bronchial wall. There are a number of known causes and several associated conditions, but the underlying cause is not known in many cases. The prevalence is unknown, but thin-section computed tomography has increased its recognition. Symptoms are of chronic productive cough, breathlessness, recurrent exacerbations usually provoked by infection, and tiredness. There may be crackles over affected areas but not in all cases, and there may be wheezes due to airflow obstruction that is largely irreversible. Subsegmental airways are permanently dilated, tortuous, and contain excess secretions. Characteristically, the elastin layer of the wall is deficient, and muscle and cartilage show signs of destruction. Increased mucus production and impaired clearance predispose to bacterial infection, which stimulates chronic inflammation in which lymphocytes predominate within the wall and neutrophils in the lumen. The inflammation causes more damage, which in turn further impairs the lung defenses, leading to more infection and a vicious cycle of events. Treatment involves daily physiotherapy to drain affected areas and appropriate antibiotics to treat infection and thus reduce inflammation.