NMDA receptor encephalitis

Anti-NMDA receptor encephalitis (also known as anti-N-methyl-D-aspartate receptor encephalitis) is a severe autoimmune disorder in which the body produces antibodies against the NR1 subunit of the NMDA receptor, a critical protein involved in synaptic transmission in the brain. This condition primarily affects the central nervous system and can lead to a rapidly progressive and potentially life-threatening encephalitis. It was first described in 2007 and is now recognized as one of the most common causes of autoimmune encephalitis. The disease typically presents in a characteristic sequence of stages. Early symptoms often include psychiatric manifestations such as anxiety, agitation, bizarre behavior, paranoia, hallucinations, and psychosis, which may initially be mistaken for a primary psychiatric disorder. This is frequently followed by neurological deterioration including seizures, movement disorders (such as orofacial dyskinesias and choreoathetoid movements), decreased level of consciousness, autonomic instability (including cardiac dysrhythmias, blood pressure fluctuations, and central hypoventilation), and speech dysfunction (ranging from reduced verbal output to complete mutism). Memory deficits are also a prominent feature. The disease disproportionately affects young women, and in a significant proportion of female patients (particularly those aged 12–45 years), an ovarian teratoma is identified as the underlying trigger, making tumor screening essential. Treatment involves a combination of immunotherapy and tumor removal when applicable. First-line immunotherapy includes intravenous corticosteroids, intravenous immunoglobulin (IVIG), and plasma exchange. Patients who do not respond to first-line treatment may receive second-line therapies such as rituximab or cyclophosphamide. Early and aggressive treatment is associated with better outcomes. The majority of patients show substantial improvement with appropriate therapy, though recovery can be slow, spanning months to years. Relapses occur in approximately 12–25% of patients and are more common when no tumor is found or when immunotherapy is delayed. Long-term follow-up and monitoring for relapse are important components of care.

Data sourced from FDA regulatory filings and ClinicalTrials.gov. Updated periodically.

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