Abstract
Rasmussen encephalitis (RE) is a rare, devastating, progressive pediatric epilepsy.
First described 60 years ago, RE continues to present challenges in diagnosis and
management. RE causes a unilateral focal epilepsy in children that typically becomes
medically refractory, results in significant hemiparesis, and causes progressive cognitive
decline. The etiology is a cell-mediated immune attack on one cerebral hemisphere,
though the inciting antigen remains unknown. While the underlying histopathology is
unilateral and RE is described as “unihemispheric,” studies have demonstrated (1)
atrophy of the unaffected hemisphere, (2) electroencephalographic abnormalities (slowing
and spikes) in the unaffected hemisphere, and (3) cognitive decline referable to the
unaffected hemisphere. These secondary contralateral effects likely reflect the impact
of uncontrolled epileptic activity (i.e., epileptic encephalopathy). Hemispheric disconnection
(HD) renders 70 to 80% of patients seizure free. While it has the potential to limit
the influence of seizures and abnormal electrical activity emanating from the pathological
hemisphere, HD entails hemiparesis and hemianopia, as well as aphasia for patients
with dominant HD. With the recent expansion of available immunomodulatory therapies,
there has been interest in identifying an alternative to HD, though evidence for disease
modification is limited to date. We review what is known and what remains unknown
about RE.
Keywords
Rasmussen Encephalitis - epilepsia partialis continua - epileptic encephalopathy
