Abstract
Background: Methacholine and histamine bronchoprovocation challenge (BPC) is an important tool in the diagnosis of bronchial hyperreactivity (BHR). Some patients respond to BPC by a significant and fast drop in forced expiratory volume in one second (FEV1). The aim of the study was to evaluate which baseline anamnestic data correlates with a fast and severe drop in FEV1.
Methods: BPC was performed in each of 1375 patients presenting with suspected bronchial asthma (BA) of either occupational (OA) - 207 patients (15%) or non-occupational origin (1168 patients - 85%). The consequential impact of the following parameters on FEV1 drop was also checked: age, sex, respiratory difficulties (dyspnoea, irritating cough, wheezing and allergic rhinitis symptoms), atopy, past medical history (PMH) of respiratory infection, smoking, chronic bronchitis. A 30% or higher FEV1 drop at bronchoprovocant dosages or concentrations lower than the planned cumulative dose or a 40% or higher FEV1 drop after inhalation of the whole bronchoprovocant dose was considered as severe.
Results: A severe FEV1 drop was found in 248 persons (18%), of which 201 patients (14.6%) were finally diagnosed with BA (52 patients with OA, 149 with non OA origin). Statistically significant FEV1 drop was found in both subgroups among patients with a PMH of whistling, among patients with atopy and smokers.
Conclusion: Caution is recommended when performing BPC in some patients, particularly in those with suspected asthma who are smokers, diagnosed with atopy and those with a PMH of wheezing. These patients may experience greater discomfort from bronchial obstruction and therefore, the provocational dose may need to be increased at a slower rate.
- © 2011 ERS
