Clinical manifestations and consequences
Bronchiectasis causes cough, usually productive of sputum. This may occur daily or less frequently in patients with early disease. These regular symptoms are punctuated by episodes of pulmonary exacerbation, often associated with culture of a potentially pathogenic organism in sputum. It is generally unclear whether these are new infections or a resurgence of chronic infection. It may be that both are important precipitants. The exact cause of pulmonary exacerbations is not well understood; however, these episodes are associated with a change in sputum colour towards green, along with an increase in cough frequency and sputum volume. This is sometimes complicated by minor haemoptysis. Individuals may feel more breathless and some will have systemic symptoms of infection, such as fever, fatigue and general malaise. Pulmonary exacerbations are associated with disease severity, and though there is no direct data for bronchiectasis, exacerbations are likely to contribute to a decline in lung function.
Chest crackles are heard on clinical examination, though in mild disease there may be no abnormal clinical signs. Finger clubbing is classically associated with bronchiectasis, but it is now a rare manifestation in this condition. Forced expiratory volume in 1 second (FEV 1 ) is frequently used for clinical monitoring to assess the severity of functional abnormality. In general, however, FEV1 changes little during exacerbations and its value as an outcome measure in clinical trials and in clinical monitoring has been questioned. As disease progresses, there is a continuing reduction in spirometric volumes. In some patients over-inflation of the lungs is prominent and this has been associated with higher mortality.
High-resolution CT is the diagnostic modality that defines bronchiectasis. Plain chest radiography is insufficiently sensitive for diagnostic purposes. There are a number of scoring schemes for reporting severity using CT, which are rarely used in clinical practice but are important for clinical research purposes. Other diagnostic tests should seek to systematically identify underlying causes such as CF, PCD, impaired immune function, allergic bronchopulmonary aspergillosis and α1-antitrypsin deficiency.