Diagnosis and prognosis of wheezing disorders in young children in the city of Sao Paulo, Southeast Brazil

Three-hundred-and-ninety-seven children aged 2-59 mo presenting to the paed iatric emergency departments of five public hospitals in Sao Paulo, Brazil, with an acute episode of lower respiratory disease were examined. The chil dren were classified into the following diagnostic categories: acute bronch itis, acute bronchiolitis, pneumonia, asthma, post-bronchiolitis wheezing a nd wheezing of uncertain aetiology. Three years after the initial study, th e homes of the children diagnosed as asthmatic or as having wheezing of unc ertain aetiology were visited to collect information on subsequent episodes of lower respiratory disease. This paper reports the proportional incidenc e of different categories of lower respiratory disease and the results of a n analysis to investigate clinical features that might distinguish wheezing children between those with asthma and those with an infectious disease. T he predictions made for children with wheezing of uncertain aetiology were then compared with the follow-up data. Recurrent wheezing disorders (asthma , post-bronchiolitis wheezing) were common in the study sample (47% of chil dren). Thirty-six percent of children with an initial diagnosis of wheezing of uncertain aetiology were diagnosed as asthmatic by another doctor over the next 3 y. We were unable to identify any clinical features that were us eful in identifying those children likely to be diagnosed subsequently as a sthmatic. Conclusions: The use of a diagnostic category similar to that which we have called "wheezing of uncertain aetiology" might help to alert physicians ea rly to the possibility of asthma without interfering in the management of t he illness. Such a classification might also be useful in epidemiological i nvestigations of the aetiology of lower respiratory diseases.