[Non specific bronchial hyperreactivity in infants].

Abstract

OBJECTIVE: To evaluate the presence of bronchial hyperreactivity (BHR) in Wheezing Babies (WB) and Normal Control Infants (C) employing the methacholine (M) bronchoprovocation test (BPT). METHODS: Fifty-one WB and 20 C, all under two years old and assisted at the Department of Pediatrics of UNIFESP-EPM, were submitted to BPT with M, having pulmonary auscultation as monitoring parameter to evaluate PCW (provocative concentration of M causing wheezing). For all tests, M diluted in saline at increasing concentrations of: 0.025, 0.125, 0.25, 0.5, 1.0, 2.5, 5.0, and 10.0 mg/ml was delivered with O2 (5 l/min) by a face mask. It was inhaled through the mouth and nose during 2 minutes of quiet tidal breathing via nebulizer with 2 ml of solution. RESULTS: None collateral effects were observed, except for tachypnea and tachycardia. There was statistically significant differences between WB (2.3 mg/ml) PCW value and C (9.2 mg/ml) (p < 0.05). At the PCW value of 2.5 mg/ml, 41% of the WB had statistically positive response (p < 0.05). This was not observed in the group C, when a positive response only occurred at the concentration of 5 mg/ml (25%). At this concentration we observed a clear cut difference between WB and C (p< 0.05). According to the severity, the highest M concentration was observed within the group displaying mild symptoms. CONCLUSIONS: We conclude that BPT utilizing PCW may be a good option for detecting BHR in young children. It is well tolerated by children, easy and safe to perform. Follow-up studies may clarify the real mean of the PCW.