[Bronchial hyperresponsiveness to methacholine in children under 4 years with recurrent bronchitis].
OBJECTIVE
To evaluate bronchial hyperresponsiveness in children under 4 years of age with recurrent wheezing bronchitis, and to determine if its presence or absence can predict the subsequent progression to a transient or persistent wheezing bronchitis phenotype.


METHODS
A bronchial challenge test was performed with methacholine using a modified tidal volume method, without sedation in a group of patients from 8 to 47 months of age with recurrent wheezing bronchitis and a control group of healthy children. A decrease in oxygen saturation of ≥ 5% or an increase in respiration rate of >50% [PCwheeze (PCw)] was considered a positive response. The patients were subsequently clinically followed up to assess their progress.


RESULTS
A total of 63 patients and 16 controls were studied (mean age 23.9 vs. 25.2 months). The PCw was lower than the control group (≤ 4 mg/ml) in 43 (68%) children from the bronchitis group (P<0.001). No significant adverse effects were observed on performing the test. After a mean follow up of 28.5 months, completed in 49 of the patients, no differences were seen between the presence of bronchial hyperresponsiveness at the beginning of the study and the subsequent progression to transient, infrequent and frequent wheezing (P=0.63).


CONCLUSIONS
A high percentage of children under 4 years of age affected by wheezing bronchitis had a bronchial hyperresponse. The subsequent progression to transient or persistent wheezing bronchitis phenotype is not associated with bronchial hyperresponsiveness.
Unidad de Neumología Pediátrica y Fibrosis Quística, Hospital Universitari Vall d'Hebron, Barcelona, Spain. idemir@vhebron.net
Inés
I
de Mir Messa
Antonio
A
Moreno Galdó
Nicolás
N
Cobos Barroso
Sílvia
S
Gartner
Carlos
C
Martín de Vicente
Sandra
S
Rovira Amigo
Alba
A
Torrent Vernetta
Santos
S
Liñán Cortés
D016535:Bronchial Hyperreactivity / Q000150:complications* / Q000175:diagnosis*; D001991:Bronchitis / Q000150:complications*; D002675:Child, Preschool; D003430:Cross-Sectional Studies; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007223:Infant; D008297:Male; D016210:Methacholine Chloride; D011446:Prospective Studies; D012008:Recurrence; D012135:Respiratory Sounds
D016210:Methacholine Chloride