Epidemiologic features of Guillain-Barré syndrome in São Paulo, Brazil.

INTRODUCTION There are few epidemiologic studies concerning Guillain-Barré syndrome (GBS). Due to difficulties with definition and lack of a standard diagnostic test of reference, GBS is not easy to study epidemiologically. We evaluate some epidemiological features of GBS in a sample of cases treated at a tertiary hospital in São Paulo, Brazil. METHOD We retrospectively reviewed all cases of GBS with hospitalization in Santa Marcelina hospital, over the period of January 1995 through December 2002. RESULTS Ninety-five cases were included in this study. Fifty-five were men and forty women, with a proportion of 1.4 men to 1 woman. The age ranged from 1 to 83 years with a mean age at onset of 34 years. GBS was less frequently observed below 15 years (18.9%) and above 60 years (16.9%). The highest frequency was observed in patients aged 15 to 60 years old (66.2%). The annual incidence rate was 0.6 cases/100,000 people. There was a highest frequency of cases during the months of September through March (62.1%). CONCLUSION Our data differs from that of other epidemiological studies in that we did not observe a bimodal distribution in age and found a seasonal pattern in hotter months.