METHACHOLINE CHALLENGES IN THE MANAGEMENT OF YOUNG-CHILDREN

Methacholine bronchial challenges (MBCs) have been used as an important diagnostic and management tool for physicians who treat children with chronic asthma. Despite this, children less than 5 years of age present significant diagnostic and management questions that can not easily be answered because of their inability to perform standard spirometry, and thus methacholine bronchial challenges. The present study was designed to evaluate with methacholine bronchial challenge small children (between 2 and 6 years of age) with the diagnosis of or a suspected diagnosis of asthma, utilizing a new method of evaluating airflow in small children through sound analysis, Computer Digitized Airway Phonopneumography (CDAP). There were 23 children in the study between the ages of 2 and 6 years with suspected asthma who could not perform pulmonary function tests. A control group consisting of 12 subjects between the ages of 8 and 38 years of age with a history of chronic cough and/or wheezing who could perform pulmonary function tests was also studied. Of the 12 patients over the age of 8 who had MBC, 11 of them had positive challenges with a fall in FEV1 of 19% or greater. The percent change in sound intensity levels from baseline range from 232% to 396% of baseline. There was greater than 200% change in mean intensity levels with a concentration of methacholine that produced a 19% fall in FEV1 in all of the eleven patients. For one individual who had a negative MBC there was only a 16% change in pulmonary function at 25 mg of methacholine with essentially no change in sound intensity level from baseline. For the 23 children who had MBCs between the ages of 2 and 6 years there were 19 in whom some type of pulmonary function testing was obtained objectively. Of these 23 children, 21 children were felt to have a positive MBC, and two completed 25 mg of methacholine administration without any change in physical examination, sound intensity levels, or measured lung function. Of the 21 children with a positive MBC, 17 were documented by reduction in lung function ranging between 32% and 70% of baseline. Of these 21 children, the changes in sound intensity levels for sound density measurements ranged between 170% of baseline and 773% of baseline. Nineteen of the 21 positive challenges had intensity levels greater than 200% with the other two being at 170 and 179% of baseline values. For the two children with negative methacholine challenges, pulmonary function was obtained in both, and there were no changes from baseline for either child in either pulmonary function or sound intensity levels. We conclude that MBCs can be performed in a quantitative fashion safely in young children between 2 and 6 years of age utilizing Computer Digitized Airway Phonopneumography.