Anti-N-methyl-ᴅ-aspartate receptor encephalitis in India: a case series and review of the literature.

Purpose: Anti-N-methyl-ᴅ-aspartate receptor encephalitis (NMDARE) is an autoimmune disorder of the central nervous system characterized by subacute- onset neurocognitive disorders, seizures, movement disorders, and prominent neuropsychiatric features affecting young adults. This case series describes the clinical profile, neuroimaging features, and outcomes in NMDARE patients and attempts to compare its findings with previously published studies in an Indian setting. Methods: All consecutive patients diagnosed with definite NMDARE over a 2-year period were evaluated and followed up with. A comprehensive literature review was conducted in PubMed, Scopus, Embase, and Google Scholar, covering studies published up to January 2025. Results: The case series included six patients (four females) aged 10-19 years presenting with super-refractory status epilepticus, dystonia, rubral tremors, and psychiatric symptoms. Tumor screening was negative in all cases. Magnetic resonance imaging of the brain revealed white matter hyperintensities in the medial temporal lobe, periventricular white matter, basal ganglia, and midbrain. Electroencephalogram abnormalities included diffuse slowing, extreme delta brush, and epileptiform discharges. Patients responded to high-dose intravenous methylprednisolone and intravenous immunoglobulin in most cases, with rituximab and cyclophosphamide administered successfully in refractory cases. Our review of Indian literature on NMDARE revealed 60 studies (115 patients), among which 48 case reports were excluded and 12 clinical studies and case series were included. Included patients were aged 2-29 years and mostly female, with similar clinical and imaging profiles to our population and a comparable low yield of tumor screening. Prognosis was good with immunotherapy, with few fatality reports. Conclusion: NMDARE patients present with protean clinical manifestations and difficult diagnostic and therapeutic challenges, resulting in an unclear prognosis. Early recognition, aggressive immunotherapy, and regular follow-up are key to better outcomes.