Study objectives: To evaluate the relationship between
bronchial hyperresponsiveness (BHR) in infants with wheezing and the
subsequent development of asthma.
Bronchial reactivity to inhaled methacholine (BRm) during the infantile
period was studied using the transcutaneous partial pressure of
oxygen (tcPo2) method. Children were
followed long-term for the development of asthma.
Patients: Fourteen children with bronchiolitis (mean age,
0.7 years) and 48 with wheezy bronchitis (mean age, 2.3 years) were
enrolled. For comparison, 40 children with asthma (mean age, 4.6 years)
and 27 healthy control subjects without chronic respiratory disease
(mean age, 2.7 years) were studied.
Consecutive doses of methacholine were doubled until a 10% decrease in
tcPo2 from baseline was reached. The cumulative
dose of methacholine (Dmin) at the inflection point of
tcPo2 (Dmin-Po2) was
Results: During > 10 years of follow-up,
seven patients with bronchiolitis developed asthma and all
patients in the higher BRm set developed asthma, compared with none in
the lower BRm set. In the wheezy bronchitis group,
Dmin-Po2 values in the 32 patients who
developed asthma were lower than those in patients who had not
developed asthma (p < 0.001).
concluded that there is a tendency for infants with a clinical
diagnosis of bronchiolitis or wheezy bronchitis and who show BHR in the
infantile period to develop asthma. The presence of increased BHR after
infantile respiratory diseases associated with wheezing may be a
prelude to the development of childhood asthma.