Seasonal variation of Guillain-Barré syndrome admission in a large tertiary referral center in southern Iran: a 10 year analysis.

INTRODUCTION Guillain-Barré syndrome (GBS) is an acute, acquired, monophasic peripheral neuropathy which has become the most common cause of acute flaccid paralysis. This is an epidemiological report on the seasonal and monthly distribution of GBS and certain patient characteristics in Shiraz, Iran. METHODS We extracted data from Namazi hospital records retrospectively in a 10 year period (January 2000 to December 2009), the largest tertiary referral center in the south of Iran. In order to compare the frequency of GBS in different months and seasons we used the Chi Square test. In a separate analysis a comparison was made between two subsets of patients regarding sex, duration of admission, month and season of admission. RESULTS From 389 cases of GBS, 232 (59.6%) were male and 157 (40.4%) were female. There was seasonal (P=0.004) and monthly (P=0.046) variation. Spring and winter had the most amount of patients, with admissions from the month of February through June inclusive accounting for 50% of all cases. CONCLUSION Our study shows that there is significant monthly and seasonal variation in the admission rate of patients with GBS in Shiraz.