Mannitol Challenge Does Not Confirm Bronchial Hyperreactivity in Some Histamine-Responsive Asthmatic Children

Abstract

Objective. The aim of this study was to compare the usefulness of mannitol provocation test to that of classical histamine challenge in children with PC₂₀FEV₁ histamine lower than 4 mg/ml. Methods. Twenty-two adolescent patients (mean age of 15.4 ± 4.1 years) with established asthma (PC₂₀FEV₁ histamine below 4 mg/ml) were included in this study. Bronchial challenge with mannitol was performed 1–2 days after the test with histamine. Results. The fraction of positive results of mannitol test was markedly lower when compared with the histamine challenge (72.7% vs. 100%, p = .015). The test was discontinued in one case due to severe coughing after inhalation of 315 mg of mannitol. Coughing during inhalation of dry mannitol powder occurred in most patients, although drinking water after subsequent doses alleviated this symptom in nearly all of them. Of note, triboelectrification of the inhaler and capsules was observed during the administration of consecutive mannitol doses, markedly hindering the delivery of this provoking agent. The relative decrease in FEV₁ resulting from bronchial provocation was significantly lower following mannitol delivery when compared with the histamine test (70.3% vs. 81.6% of resting value, p < .001). Significant correlation was not observed between the values of PC₂₀FEV₁ histamine and PD₁₅FEV₁ mannitol levels. Conclusions. Bronchial challenge with mannitol can be used as a screening test in everyday practice, but one cannot exclude bronchial hyperresponsiveness based on its negative results. Moreover, its usefulness is limited by the influence of static on the delivery of sequential mannitol doses and coughing which can be often associated with mannitol inhalation.

• asthma
• bronchial hyperresponsiveness
• provocation
• screening
• spirometry