Childhood-onset nonprogressive chronic encephalitis

•Variants of pathologically-determined RE have been reported.•We describe a series of patients with childhood-onset CE.•There was limited progression on EEG, MRI, and clinical and neuropsychological testing.•Absence of EPC may implicate a nonprogressive course.•The spectrum of childhood-onset CE should include nonprogressive variants.

PurposeThe purpose of this study was to describe a series of patients with pathologically proven chronic encephalitis who had a nonprogressive course during a long follow-up, suggestive of a “benign” variant of Rasmussen's encephalitis (RE).MethodsFour patients who were referred to our Comprehensive Epilepsy Program at London Health Science Centre in London, Ontario, were diagnosed with chronic encephalitis on a pathological basis after epilepsy surgery to treat their partial-onset seizures.ResultsNone of our four cases followed the typical course of RE despite their childhood-onset seizures between ages 2 and 12 years. One was preceded by a mild head trauma and fever at onset. None had epilepsia partialis continua (EPC). Their long-term follow-up revealed a nonprogressive form of the syndrome with respect to the neurological examination, EEG, MRI, and neuropsychological findings.ConclusionThese cases extend the spectrum of childhood-onset intractable epilepsy with chronic encephalitis to include nonprogressive variants of RE. The absence of EPC may be a prognostic indicator of a nonprogressive course.