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Anti-NMDA Receptor Encephalitis — RACP Adult Medicine MCQ

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HardNeurologyAnti-NMDA Receptor EncephalitisRACP Adult Medicine

A 35-year-old man presents with acute psychosis, seizures, and autonomic instability. MRI brain shows bilateral medial temporal lobe signal abnormality on T2/FLAIR. CSF shows lymphocytic pleocytosis with normal glucose. Anti-NMDA receptor antibodies are positive. What should be investigated in male patients?

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Correct answer: C — Testicular teratoma

Anti-NMDA receptor encephalitis is the most common autoimmune encephalitis. In women, it is strongly associated with ovarian teratoma (~50%). In men, the association with tumours is less common but testicular teratoma should be screened for. Treatment includes tumour removal (if found), first-line immunotherapy (IV corticosteroids, IVIg, or plasma exchange), and second-line agents (rituximab, cyclophosphamide) for refractory cases. Early aggressive treatment improves outcomes.

Reference: eTG – 2025 – Neurology; Lancet Neurology – 2019 – Autoimmune Encephalitis Review