Anti-NMDA Receptor Encephalitis and Rasmussen-like Syndrome: An Association?

Abstract Background N-methyl-D-aspartate receptor (NMDA) encephalitis is an immune mediated condition that has a broad spectrum of manifestations, including seizures, coma, psychosis, and focal neurologic deficits. Though usually a diffuse process, unihemispheric involvement mimicking early stages of Rasmussen’s encephalitis (RE) can occur. RE is a unique syndrome consisting of progressive hemiplegia, drug resistant focal epilepsy, cognitive decline, and hemispheric brain atrophy contralateral to the hemiplegia. Patient Description We describe the case of a 2 year old female with progressive right side weakness and epilepsia partialis continua, concerning for early RE, who tested positive for anti-NMDA receptor (NMDAR) antibodies. The patient had complete clinical recovery with immunotherapy. NMDAR antibodies were absent 3 weeks and again at 1 year after the first treatment of IVIG. Conclusions There is a limited number of case reports of Rasmussen’s-like encephalitis with NMDAR antibody positivity. Thus, the clinical significance of this association is yet to be determined. Additionally, several other antibodies have been reported in patients with RE. With the lack of a consistently reported antibody in RE and given the temporary presence of the NMDAR antibody in this patient, our case raises the question: is the presence of NMDAR antibody the cause of the symptoms or rather secondary to the pathogenic process?