Bilateral Rassmussen's Encephalitis: A Rare and Difficult Entity—Case Report

Introduction: Rasmussen encephalitis is a rare chronic disorder characterized by unilateral inflammation of the cerebral cortex, drug resistant epilepsy, and progressive neurological deterioration. Functional hemispherotomy is the choice of management in drug-resistant cases. The existence of bilateral disease is debated.

Case Report: A 12-year-old girl, born of a nonconsanguineous caesarean section with normal milestones had seizures since 9 years of age. She started with left focal motor (tonic–clonic) seizures with lower limb onset, which evolved to epilepsia partialis continua (EPC) over time, resistant to multiple antiepileptics. Her MRI revealed right temporo-parieto-occipital gliosis and atrophy and EEG showed right hemispherical slowing with superimposed epileptiform discharges. Left hemisphere was completely normal on EEG. She was diagnosed as a case of Rassmussen's encephalitis after ruling out other etiologies and given immunotherapy. After initial failure with steroids, IVIG and pheresis, she later responded favorably with rituximab but after 6 months, developed right-sided focal motor seizures with lower limb onset which over a short period of time progressed to EPC. EEG revealed slowing in bilateral hemispheres with left hemispherical interictal epileptiform discharges and seizure onset from left-sided (central and midline) channels. MRI revealed T2/FLAIR hyperintense signal in left frontal parasagittal region corresponding to the leg region. She was again given rituximab with modest benefit.

Conclusion: Rassmussen's encephalitis can be rarely bilateral. Management of such patients is difficult since surgical option is not feasible owing to bilaterality.