Читать книгу Respiratory Medicine - Stephen J. Bourke - Страница 45

This is a whistling or musical noise that is characteristic of air passing through a narrow tube. The sound of wheeze can be mimicked by breathing out almost to residual volume and then giving a further sharp, forced expiration. Wheeze is a characteristic feature of airway obstruction. It is seen in asthma. In theory, it might be expected in COPD but is rarely found in practice. In COPD, auscultation is more likely to reveal diminished (quiet) breath sounds. It can also occur in pulmonary oedema when airway walls are swollen with fluid. In asthma, wheeze is characteristically worse on waking in the morning and may be precipitated by exercise or cold air. Wheeze that improves at weekends or on holidays away from work and deteriorates on return to the work environment is suggestive of occupational asthma. Wheeze occurs on expiration. ‘Wheeze’ on inspiration is not wheeze, it is stridor – indicating obstruction of the central airways (e.g. obstruction of the trachea by a carcinoma): an important distinction not to miss.

When wheeze is present, airway obstruction is present. Wheeze, however, is not a reliable indicator of obstruction. It is often absent in COPD and severe, life‐threatening asthma may be associated with a ‘silent chest’.