Rasmussen's encephalitis and the new hat

Neurology 1996;46:9-11

The prototype case of the syndrome now designated as Rasmussen's encephalitis was identified in 1941 in a 7-year-old boy who developed right-sided seizures and subsequently slight right arm weakness; a left cortical biopsy revealed encephalitis. ^[1] By 1945 he had progressed to moderate right hemiparesis. A larger cortical resection again indicated inflammation. Seizures continued and right hemiplegia and hemianopia evolved. A left hemispherectomy was performed in 1956; sparse perivascular inflammation and glial nodules were found. Dr. Wilder Penfield, consulting in this case, raised the issues which continue to be debated to the present day. Is the encephalitic process the primary abnormality or a secondary response to the recurrent seizures? Why should an encephalitic process be unilateral? Can recurrent seizures lead to tissue destruction? Dr. Penfield, skeptical of the postulate that the syndrome was a primary inflammatory disorder, offered a new hat to anyone who proved him wrong.

The clinicopathologic syndrome of childhood-adolescent onset of unilateral seizure disorder with progressive hemiplegia consequent to focal cortical inflammation and tissue destruction has now been recognized and described worldwide. The complete spectrum of the syndrome in terms of age of onset, rate of evolution, topographic distribution of pathology, natural course, and response to therapy continues to be debated. In the series of 48 cases from the Montreal Neurological Hospital reviewed by Oguni et al, ^[2] the mean age of disease onset was 7 years (range, 1-15 yr), one patient was aged 30 years. The series included cases that stabilized spontaneously and at least one case that improved; these observations create a dilemma in evaluating open-label therapy claims. Neuroimaging done serially on patients demonstrates progressive tissue destruction, but to date this measure has not been included in therapeutic outcome assessments. Pathologic studies of cases with serial samples collected from repeated surgery and …