To study the epidemiology, clinical features, diagnosis and management of Anti N-Methyl D-Aspartate Receptor Encephalitis (NMDARE) in South Asian population.

The clinical manifestations of anti NMDARE in Western populations are well studied, yet poorly understood in South Asian patients. Despite South Asia comprising a quarter of the global population, research on this topic remains limited. To address this research gap and gain insights into the clinical characteristics of NMDARE in this vast population, we conducted a systematic review of literature from the region.

We adhered to PRISMA guidelines. PubMed search was done for case series and observational studies (cohort, retrospective, prospective and ambispective) from South Asia.

We analyzed 17 studies comprising 257 cases, 69.26% being female and a median age of 12.42 years. Cerebral Spinal Fluid antibodies (CSF) and serum antibodies were positive in 96.33% and 70.89% respectively. Common clinical features included behavioral disturbances (82.88%), seizures (80.54%), impaired awareness (71.43%), movement disorders (59.22%) and memory disturbances (56.79%). Magnetic Resonance Imaging (MRI) abnormalities were observed in 47.06% of cases, most commonly affecting the temporal lobe and limbic system (24.46% each). Abnormal Electroencephalogram (EEG) findings were present in 82.3% of patients. Treatment included first-line immunotherapy with pulsed methylprednisolone, intravenous immunoglobulin, or plasma exchange, while rituximab and/or cyclophosphamide were considered for inadequate responders. Outcomes showed complete recovery (52.14%), partial recovery (37.35%), and severe disability (3.89%), with 11% experiencing relapses, and a 4.6% mortality rate.

Anti-NMDARE in South Asia exhibits a notable female predominance, but with a lower median age (12.42 years). Clinical features, laboratory/imaging findings closely align with Western populations. Similar treatment modality was followed with comparable outcome.