Rasmussen encephalitis

Abstract

Rasmussen encephalitis (RE) is a rare, inflammatory, and possibly immuno-mediated disease that typically affects one hemisphere. The two cardinal symptoms are progressive neurological deficits and intractable seizures, often in the form of epilepsia partialis continua and recurring epileptic status. Distinctive MRI features include progressive unilateral focal cortical atrophy and gray or white matter high-signal changes with basal ganglion involvement. Histopathology is characterized by brain inflammation dominated by T cells, microglial activation, and microglial nodules, followed by neuronal loss and astrogliosis. The diagnosis of RE, which may be particularly challenging in the initial stages, is based on clinical and laboratory findings. The diagnosis requires the exclusion of other causes of epilepsia partialis continua, and other cerebral focal inflammatory diseases. The treatment of RE is often demanding: antiepileptic drugs are of limited effect, whereas the surgical exclusion of the affected hemisphere offers a very high chance of seizure freedom but at the price of irreversible neurological deficits. By contrast, long-term immunotherapy may delay hemispheric tissue loss and neurological deficits, but has a lesser effect on total seizure burden. Given that the severity of symptoms varies among different patients and phases, the therapeutic strategy, including medical and surgical options, must be tailored to the need of each patient.