Relationship between bronchial hyperresponsiveness and development of asthma in children with chronic cough

Abstract

To evaluate the relationship between bronchial hyperresponsiveness (BHR) and the development of asthma in children with chronic cough, we performed methacholine inhalation challenges and transcutaneous oxygen pressure (tcPO2) measurements in 92 children with chronic cough aged from 1-13 years (55 boys and 37 girls; mean, 5.3 years) and followed them for > or = 10 years. Forty-four age-matched children with asthma (24 males and 20 females; mean, 6.5 years) and 44 age-matched children without cough or asthma served as controls (18 males and 26 females; mean, 4.6 years). Consecutive doubling doses of methacholine were inhaled until a 10% decrease in tcPO2 from baseline was observed. The cumulative dose of methacholine at the inflection point of the tcPO2 record (Dmin-PO2) was considered to represent hyperresponsiveness to inhaled methacholine. After 10 years or more of follow-up, 60 of the 92 subjects with cough answered our questionnaire, and 27/60 had been diagnosed with asthma. There was a statistical difference in Dmin-PO2 between the children who presented with chronic cough originally and who developed asthma (asthma-developed group) and those who did not develop asthma (asthma-free group). There was no difference in the value of Dmin-PO2 between the asthma-developed group and the asthma group, or between the asthma-free group and the age-matched control group. Among the children with chronic cough, there was no difference in Dmin-PO2 between girls and boys, either in the asthma-developed group or in the asthma-group. We conclude that 45% of the children with a chronic cough in early life developed asthma, and that BHR in children with chronic cough during the childhood period is a strong risk factor for the development of asthma.

Guidelines for Evaluating Chronic Cough in Pediatrics

“…This is in contrast to that in adults with chronic cough in whom some have suggested the use of an airway inflammatory profile (ie, levels of primarily eosinophils) to direct therapy. 74 Older studies [75][76][77][78] have stated that the presence of AHR in children with cough is said to be representative of asthma. 71 The presence of AHR does not mean that asthma is present in children, 72 and the demonstration of AHR in a child with isolated cough is unlikely to be helpful in predicting the later development of asthma 73 or the response to asthma medications.…”

“…69,70 Tests for Airway Hyperresponsiveness Tests for airway hyperresponsiveness (AHR) are not used in routine practice in most pediatric pulmonary laboratories to diagnose asthma. However, these studies [75][76][77][78] were not placebo-controlled, and in them confounders were not adjusted for or unconventional definitions of AHR were used. 74 Older studies [75][76][77][78] have stated that the presence of AHR in children with cough is said to be representative of asthma.…”

Changes in the breath sound spectrum during methacholine inhalation in children with asthma

“…The study participants included a total of 49 paediatric outpatients (mean age: 10.2 ± 2.5 years; range: 5–16 years; male:female: 33: 16) who were treated at the Tokai University Hospital from 1 April 2012 to 31 March 2015 (Table ). The inclusion criteria were as follows: one or more positive specific IgE value (>0.7 UA/mL), recurrent wheezing and bronchial hyperresponsiveness by methacholine inhalation challenge . All of the participants had been diagnosed with atopic‐type asthma by a physician.…”

Medico-social aspects of patients with bronchial asthma

“…k o n t a k t 1 7 ( 2 0 1 5 ) e 1 0 3 -e 1 1 5 chronic coughing symptoms, no differences were found between them, and bronchial hyper-reactivity and asthma were subsequently developed ten years later [42].…”