Clinical findings, imaging characteristics and outcome in catastrophic post-encephalitic epilepsy

Objectives:The aim of this study is to characterize the clinical features a nd prognostic factors for intractable, post-encephalitic epilepsy. Methods: We studied retrospectively 42 patients (26 men) evaluated between 1982 and 1999. MRI, neuropsychological findings, interictal and ictal scalp EEC were reviewed for all patients. Fifteen patients had additional stereo EEG (SEEG) studies: Results: The mean age at encephalitis was 17 years (SD = 15.5); etiology wa s identified in 18 patients. During the acute illness, 79% had status epile pticus (SE) or recurrent seizures and 76% were in coma; mean Glasgow outcom e scale (COS) was 3.6 (SD = 0.8). The mean latency to seizure onset was 0.8 years (SD = 1.9). The majority (72%) presented with complex partial seizur es with or without secondary generalization. According to interictal epilep tiform findings and the predominant seizure onset pattern as found on scalp EEC, patients were unilateral temporal (UTLE) = 8, bilateral temporal (BTL E) = 12, and extratemporal/multifocal or generalized (ETMFE) = 22 patients. MRI atrophy and/or signal changes were unilateral temporal in 7 (18%), bil ateral temporal in 5 (13%), multilobar/diffuse in 20 (51%), and absent in 7 (18%). ANOVA revealed significant differences in mean GOS between UTLE ver sus BTLE and ETMFE (4.7 Versus 3.2 versus 3.6; p < 0.0001), but not in age at encephalitis. Latency to the first unprovoked seizure was shorter in pat ients with ETMFE compared to UTLE and BTLE (p < 0.01). Surgery was performe d in 24 patients. The best outcome was obtained in UTLE (7/8 class I and ii ). In the others, outcome was poor in the majority (13/16 class III and IV) . Conclusion: There is a small subgroup of patients with postencephalitic UTL E for whom the outcome is favorable. The majority of our patients had multi focal seizure onset with BTLE and ETMFE, and poor outcome after surgical tr eatment.