[Relation between extent of bronchial reactivity and need for medication (therapy) in bronchial asthma in children]

In 42 schoolchildren we have prospectively examined the relationship between the degree of bronchial responsiveness to methacholine and the treatment to control asthma. Following a standardized protocol for methacholine provocations we determined the provocation concentration causing a fall in FEV1 of 20% (PC20). Patients were grouped into 1 (n = 13), those who required no medication; 2 (n = 8), those who required beta 2-agonists on demand and 3, those who required beta 2-agonists and additional DSCG or topic steroids. Mean PC20 in group 1 was 3.55 mg/ml, in group 2 1.38 mg/ml and in group 3 0.37 mg/ml. There was a significant difference between each group. Generally spoken, those patients showing a high level of bronchial responsiveness to methacholine required more medications to control their asthma symptoms. However, an overlap of responsiveness in each treatment group was noted. The results of the present study show that measurement of airway responsiveness may be useful in some patients to better assess the necessary treatment to control asthma.