RT Journal Article
SR Electronic
T1 Bronchodilator responsiveness following methacholine-induced bronchoconstriction in children with clinically highly suspected asthma
JF European Respiratory Journal
JO Eur Respir J
FD European Respiratory Society
SP P1946
VO 40
IS Suppl 56
A1 Tae Won Song
YR 2012
UL http://erj.ersjournals.com/content/40/Suppl_56/P1946.abstract
AB Rationale: Patients who were clinically highly suspected asthma occasionally showed negative results in methacholine challenge test (MCT), but showed higher bronchodilator responsiveness (BDR) after methacholine induced bronchoconstriction. The aim of this study was to assess the usefulness of BDR following methacholine-induced bronchoconstriction as a tool for the therapeutic plan in clinically suspected asthmatic patients with negative results in MCT. Methods: MCT was performed in 530 children for evaluation of asthma. Immediately after MCT, patients were asked to inhale short-acting beta2 agonists to evaluate BDR. BDR was measured as the percent increase in FEV1 after treatment. Total serum IgE levels, total eosinophil counts, and specific IgE levels were measured in most children. Schedule visits at 1-month to 6-month intervals were done for 3months to 4 years. Results: Among 530 children, 219 patients showed negative results (PC20 >25mg/mL) in MCT. Out of children with negative MCT, 37 patients expressed over 12% increase (high BDR) and 182 patients expressed under 12% increase (low BDR) in FEV1 after bronchodilator following methacholine induced bronchoconstriction. Among patients with high BDR and negative MCT, 37.8% patients were required inhaled corticosteroid therapy for control of their symptoms. But, among patients with low BDR and negative MCT, only 10.8% patients were required inhaled corticosteroid. Conclusion: In clinically highly suspected asthmatic children with negative MCT, BDR following methacholine-induced bronchoconstriction seems to play a considerable role for the decision of treatment with inhaled corticosteroid.