Pediatr Allergy Respir Dis.  2009 Mar;19(1):28-37.

The Relationship between Wheezing during Methacholine Bronchial Challenge and the Severity of Acute Asthma Exacerbation in Asthmatic Children

  • 1Department of Pediatrics, Inha University College of Medicine, Incheon, Korea.


Global Initiatives for Asthma (GINA guideline) 2005 suggests that the pitch and intensity of wheezing as the determinating factor for the severity of asthma exacerbation. However, there have not yet been sufficient data to support the correlation between wheezing and the severity of asthma exacerbation. This study was aimed to estimate the relationship between wheezing threshold and the level of forced expiratory volume in 1 second (FEV1).
Among 370 pediatric patients who visited Inha University Hospital between May 2005 and June 2006, who underwent the methacholine bronchial challenge tests in order to diagnose asthma, 228 patients with PC20 less than 16 mg/mL were examined. Medical history, physical examination, skin prick test, eosinophil count and total IgE level in peripheral blood, and nasal smear for eosinophil count were performed.
Among the 228 patients 127 (55.7%) showed wheezing during the methacholine challenge test. Among the patient with wheezing 82 patients (36%) showed more than 20% fall of FEV1, and the other, 45 patients (19.7%), showed less than 20% FEV1%fall. One hundred one patients (43.3 %) did not show any wheezing until the %fall of FEV1 was below 20%. The geometric mean (range of 1SD) [2.29 (0.86-6.13) mg/mL] of methacholine PC20 of the 127 patients with wheezing was significantly lower than that [4.11 (1.82-9.24) mg/mL] of the 101 patients without wheezing (P<0.001). The geometric mean (range of 1SD) of methacholine PC20 in the 143 patients with positive skin prick test results was 2.57 (0.97-6.81) mg/mL, which was significantly lower than that of the 37 patients with negative results [3.69 (1.57-8.66) mg/mL] (P<0.001).
We could learn that most wheezing patients showed more than 20% fall of FEV1. Therefore, it is suggested that the asthmatic children with wheezing were regarded and treated as moderate or more severe state


Wheezing; Threshold; Asthma, FEV1; Bronchial challenge test; Methacholine
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