A rare case of anti-NMDA receptor encephalitis associated with an ovarian teratoma (2021)

Type of publication:
Conference abstract

*Korrapati S.; *Sahu B.; *Parry-Smith W.

BJOG: An International Journal of Obstetrics and Gynaecology; May 2021; vol. 128 ; p. 135

Introduction Anti-N-methyl-D-aspartate receptor (anti-NMDAR) encephalitis is an auto-immune and paraneoplastic encephalitis with an incidence of 1.5 per million population per year. About 80% are women and nearly half of them have an ovarian teratoma. It is associated with antibodies against NR1 or NR2 subunits of NMDA receptor in cerebrospinal fluid (CSF) and serum. Given the rarity of occurrence, it remains an unrecognised entity among gynaecologists. Hence, we report a case of anti-NMDAR encephalitis associated with ovarian teratoma. Case report A 34-year-old woman attended under physicians with confusion, memory loss and agitation. She had a history of bilateral ovarian teratomas removed in 2018. Patient's vitals and neurological examination were normal. She was unable to perform motor tasks. Routine laboratory examinations and CT head were normal except for mild leucocytosis (WCC 13.3). She was empirically treated for infectious encephalitis. CSF examination showed normal glucose and protein, negative for viral PCR, gram staining but positive for NMDA receptor antibodies, prompting us to explore for an underlying tumour. CT abdomen/pelvis showed 9mm focus of fat suspicious of residual/recurrent teratoma in right adnexa. PET CT showed no metabolically active pathology. She was commenced on first line immunotherapy, IV Methylprednisolone followed by IV immunoglobulins and then plasma exchange. Following gynaecology MDT decision, she underwent laparoscopic right oophorectomy. Histopathology revealed a right ovarian teratoma. Postprocedure her neurological symptoms including confusion & memory retention improved considerably. Conclusion Anti-NMDAR encephalitis is rare but potentially debilitating condition. It is important to remove any associated ovarian teratoma promptly to improve outcome.

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