64.: Anti-N-methyl-D-aspartate-receptor (NMDAR) encephalitis after viral meningitis

Abstract

We report a woman with non-tumour associated anti-N-methyl-D-aspartate-receptor (NMDAR) encephalitis with a prominent prodromal meningitic syndrome and an usually high cerebrospinal fluid (CSF) white cell count (WCC) and protein. CSF polymerase chain reaction (PCR) was negative for viruses and bacteria; however a nasopharyngeal swab returned a positive PCR for enterovirus. These findings suggest a preceding viral meningitis trigger for NMDA encephalitis which has previously only been described to our knowledge after herpes simplex virus encephalitis. An 18-year-old woman presented with headache, fever (39°C) and meningism. CSF showed WCC 668×10^f/L, 96% lymphocytes, red blood cell 37×10^f/L, protein 1.31g/L, and normal glucose. Intravenous (IV) acyclovir and ceftriaxone were started for provisional viral meningitis and continued until CSF PCR returned negative. MRI of the brain showed subtle cortical enhancement consistent with meningitis. She was discharged on day 7. She returned on day 8 after three generalised tonic-clonic seizures. Electroencephalogram (EEG) showed mild right hemispheric slowing. IV acyclovir and levetiracetam were given. Over 24hours she developed disinhibition and grandiose delusions. Over 7days she developed mutism, autonomic disturbance, further seizures, and required intubation and intensive care unit admission. Methyl-prednisone 1g daily for 10days was given without benefit. Progress EEG showed right hemispheric and then generalized delta activity. Prominent intermittent chewing movements and oro-lingual-facial dyskinesias were noted without EEG epileptiform correlation. Anti-NMDAR antibodies were detected in CSF but not serum, confirming anti-NMDAR encephalitis. Malignancy screening was negative. IV immunoglobulin G (0.4g/kg/day) was given for 10days and she continued on prednisone 50mg daily. She remained unconscious with oro-lingual-facial dyskinesias. Rituximab 1g was given 3days after last IV immunoglobulin G dose and again 2weeks later. Six weeks post diagnosis she was awake, intermittently obeying commands and not ventilator dependent. We report a patient with anti-NMDAR encephalitis which developed after an initial presentation with presumed viral meningitis. About 70% of patients with NMDA encephalitis have prodromal symptoms consisting of headache, fever, nausea and/or diarrhoea. This case highlights that the prodromal syndrome in anti-NMDAR encephalitis may be associated with much higher CSF cell counts and protein than previously reported when triggered by preceding viral meningitis.