Magnetic Resonance Imaging and Electroencephalograhic Characteristics in Two Cases of Fatal Eastern Equine Encephalitis (EEE) (P4.317)

OBJECTIVE: We describe novel EEG and MRI findings in two confirmed fatal cases of Eastern Equine Encephalitis BACKGROUND: Eastern Equine Encephalitis (EEE) is the most severe of the mosquito-borne encephalitides, occurring at a frequency of 0.003 cases per 100,000 population from 1999 to 2007, with a case fatality estimated at 36% in one large study. MRI findings in cases of EEE are previously described as T2 FLAIR linear signal changes in the external capsule or in the rim of the putamen, with previously postulated thoughts that the degree of MRI findings may correlate with the severity of EEE (2). EEG findings in EEE have been described in the literature as a slow background. DESIGN/METHODS: We review two confirmed cases of fatal Eastern Encephalitis admitted to a large tertiary medical center in August 2012, with EEE confirmed based on serological markers (CSF and Serum) and exclusion of other potential infectious etiologies. A Pub med literature search was performed noting previously reported radiographic and electroencephalogram findings in EEE patients. RESULTS: EEG monitoring of our patients revealed periodic 0.5-0.25Hz transients, however, the voltages of these transients were significantly lower (~20 to 40 µV) than those typically seen in patients with HSE (~100 to 500 µV). MRI imaging revealed a pattern of T2 hyperintensity in the lentiform nuclei without any particular post-gadolinium enhancement pattern. CONCLUSIONS: The consistency of the distinctive MR and EEG findings in the two cases we report suggests a pattern which may be pathognomonic for EEE in the appropriate clinical and epidemiological context. These findings could aid in earlier recognition. The pathophysiology for selective viral tropism of EEE to particular brain regions remains unknown but is an area for future research. S tudy Supported by: None. No funding obtained. Disclosure: Dr. Babi has nothing to disclose. Dr. Applebee has received personal compensation for activities with the DER-401 Publications Steering Committee. Dr. Applebee has received research support from Serono Inc., Sanofi-Aventis Pharmaceuticals Inc., Acorda Therapeutics, Biogen Idec, Novartis, Genentech Inc., and Opexa Therapeutics. Dr. Shapiro has received personal compensation for activities with NuPathe Pharmaceuticals. Dr. Raleigh has nothing to disclose. Dr. McSherry has nothing to disclose.