Objective: To assess the annual incidence of typical Guillain-Barré syndrome (GBS) and its main variants (atypical GBS) in a well-defined population from a large area.
Material and methods: A population-based prospective survey of GBS was undertaken during the calendar year 1996 in Lombardy, Italy (population 8,891,652). Typical and atypical GBS was diagnosed using the National Institutes of Neurological and Communicative Disorders and Stroke (NINCDS) and Ropper criteria. Eligible cases were hospital inpatients traced through a regional registry, the hospital discharge diagnoses, and an ongoing case-control study. Diagnostic and demographic findings were collected for each case. Complete clinical and laboratory features were available for 80% of cases.
Results: A total of 138 patients (males 74; females 64) aged 2-91 years fulfilled the diagnostic criteria for typical GBS (128) or atypical GBS (10). GBS variants included Miller-Fisher syndrome (four cases), cranial polyneuritis (three cases), pure motor GBS (two cases), and sensory loss with areflexia (one case). The crude annual incidence of GBS was 1.55 per 100,000 (typical GBS 1.43; atypical GBS 0.11; male 1.67; female 1.43; age <35 years, 0.79; 35-54 years, 1.33; 55-74 years, 3.22; 75+ years, 4.67). The overall rate was 1.58 when age- and sex-adjusted to the 1996 Italian population. Previous infections were reported for 37% of patients. The electrophysiological findings indicated demyelination in 51%, primary axonopathy in 14%, and mixed myelin and axon involvement in 27%.
Conclusions: The incidence of typical GBS is comparable with that in other reports using the NINCDS diagnostic criteria. Atypical GBS accounts for a limited number of cases.