Clinical characteristics and prognostic factors of postencephalitic epilepsy in children.

The goal of this study was to clarify the clinical characteristics and prognostic factors of childhood postencephalitic epilepsy. Forty-four patients (20 boys and 24 girls; age range 21 months to 17 years, mean age 8.1 +/- 4.6 years) with postencephalitic epilepsy were selected from the 798 epileptic children treated and followed up at our hospital between 1993 and 2003. The clinical data included clinical features, electroencephalograms (EEGs), and neuroimages, all reviewed and analyzed retrospectively. Based on their post-treatment seizure outcomes, the children were divided into favorable (n = 20) and poor outcome groups (n = 24). Between the two groups, the age at encephalitis, cerebrospinal fluid findings, and seizure type were comparable. Factors indicating a poor prognosis for these patients during the acute phase of encephalitis were (1) status epilepticus occurring as the first seizure (P < .005), (2) slow background activity (P < .001) and multifocal spike discharges on EEGs (P < .01), and (3) herpes simplex viral encephalitis (P < .01). Our findings indicated that patients with status epilepticus and multifocal spikes on EEG during acute encephalitis have an increased risk of developing intractable epilepsy. To improve the outcome of postencephalitic epilepsy, intervention must occur earlier in the encephalitis stage.