General description

Rasmussen's encephalitis is a rare, chronic, progressive neurological disorder characterized by focal seizures, progressive cortical deficits such as hemiparesis, and progressive cortical atrophy. It is an autoimmune inflammatory disease mediated by cytotoxic T cells, typically presenting with seizures, often epilepsia partialis continua (EPC). While the average age of onset is 9 years old, it can occur in adults as well. Some cases may involve cortical malformations.

The disease is thought to be caused by an autoimmune inflammatory process, with cytotoxic T cells playing a central role. Seizures are typically focal, with EPC occurring in about half of the cases. Seizure frequency gradually increases and may occur in clusters, but tends to decrease after several years as the disease enters the residual phase. Rasmussen's encephalitis is classified into rapidly progressive (mainly in childhood) and slowly progressive (adult-onset) forms. The disease course is divided into three stages: prodromal (seizure onset to hemiparesis), acute (hemiparesis to fixed neurological deficits), and residual (stable deficits).

Cerebrospinal fluid (CSF) analysis may show an initial increase in cell count, but this subsides quickly. Measuring granzyme B, secreted by cytotoxic T cells in the CSF, is important for diagnosis, and antibodies to the glutamate receptor GluN2B can also be informative.