Seasonal variation in hemorrhage and focal neurologic deficit due to intracerebral cavernous malformations

The objective was to determine if there was seasonal variation in the month of symptom onset in patients with intracerebral cavernous malformations (ICM). Patients seen at our institution between 1989 and 1999 with ICM identified from a radiologic database were included. Demographic data and symptoms at onset were abstracted. Symptomatic patients in this ICM database were included if the month of symptom onset was known. Comparison of proportions of patients presenting in fall and winter and during flu season were performed with the chi squared test and Fisher's exact test with significance at p < 0.05. Of 292 patients identified, 179 patients had symptomatic ICM. Of these, 135 patients with symptomatic ICM were identified for whom the exact month of symptom onset was known. Eighty-seven (64.4%) presented with intracerebral hemorrhage (ICH) or focal neurologic deficit (FND) and 48 (35.6%) due to seizures. When assessing all 135 patients, 75 (55.5%) presented in the fall and winter compared to the spring and summer (p = 0.1962). Eighty-three (61.4%) patients presented during flu season (p = 0.0074). When assessing only those initially presenting with ICH or FND, 53 (60.9%) patients presented in the fall and winter compared to spring and summer (p = 0.041) and 54 (62.8%) presented during flu season (p = 0.017). Patients with recurrent ICH more commonly presented in the fall and winter compared to summer and spring and during flu season. Patients with ICM who presented with FND or ICH or had recurrent ICH tended to present in the fall and winter or during flu season.