Relationship between bronchial hyperresponsiveness and development of asthma in wheezy infants.
OBJECTIVE
To evaluate the relationship between bronchial hyperresponsiveness (BHR) in infants with wheezing and the subsequent development of asthma.


METHODS
Bronchial reactivity to inhaled methacholine (BRm) during the infantile period was studied using the transcutaneous partial pressure of oxygen (tcPO(2)) method. Children were followed long-term for the development of asthma.


METHODS
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.


METHODS
Consecutive doses of methacholine were doubled until a 10% decrease in tcPO(2) from baseline was reached. The cumulative dose of methacholine (Dmin) at the inflection point of tcPO(2) (Dmin-PO(2)) was recorded.


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-PO(2) values in the 32 patients who developed asthma were lower than those in patients who had not developed asthma (p < 0.001).


CONCLUSIONS
We 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.
Department of Pediatrics, Gunma University School of Medicine, Maebashi, Japan. saga@akagi.sb.gunma-u.ac.jp
R
R
Saga
H
H
Mochizuki
K
K
Tokuyama
A
A
Morikawa
D001249:Asthma / Q000453:epidemiology / Q000503:physiopathology*; D001785:Blood Gas Monitoring, Transcutaneous; D016535:Bronchial Hyperreactivity / Q000503:physiopathology*; D001985:Bronchial Provocation Tests; D001988:Bronchiolitis / Q000503:physiopathology*; D001991:Bronchitis / Q000503:physiopathology*; D016085:Bronchoconstrictor Agents; D016022:Case-Control Studies; D002675:Child, Preschool; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007223:Infant; D008297:Male; D016210:Methacholine Chloride; D012135:Respiratory Sounds / Q000503:physiopathology*; D013997:Time Factors
D016085:Bronchoconstrictor Agents; D016210:Methacholine Chloride