The usefulness of bronchial challenge tests in the diagnosis of occupational asthma

Abstract

Bronchial hyperresponsiveness (BHR) is the individual ability to respond with bronchoconstriction to a variety of specific and nonspecific stimuli which do not cause these symptoms among healthy subjects. Bronchial hyperresponsiveness is one of the hallmark features of asthma. The degree of bronchial hyperresponsiveness is variable among individuals with asthma and may correlate to its severity (the more severe asthma the higher bronchial hyperreactivity). Bronchial hyperresponsiveness is evaluated by performing bronchial provocation test (BPT). Provocation tests are classified – according to their mechanisms – into direct and indirect tests. Direct challenge tests are highly sensitive and they are used primarily to rule out asthma. In contrast, provocation tests with indirect stimuli are less sensitive but more specific to the direct tests; they are used generally to confirm the diagnosis of asthma and they allow for more accurate conclusions about inflammatory lesions in the case of a patient. Bronchial provocation tests play a significant role in occupational medicine. They are particularly relevant to be performed prior to employment, during periodic examinations, and to diagnose and monitor both occupational asthma and work-related asthma. This article presents selected bronchial provocation tests and their usefulness in the diagnosis of occupational asthma.