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Anti-NMDA receptor encephalitis with initial negative markers: diagnostic and therapeutic challenges of a refractory case with 9-month-long follow-up
  1. Camilla Cascardo1,
  2. Alexander Ismail2,
  3. Joseph Fullmer3 and
  4. Francisco Davila4
  1. 1Oakland University William Beaumont School of Medicine, Rochester, Michigan, USA
  2. 2Neurology, William Beaumont Hospital, Royal Oak, Michigan, USA
  3. 3Pathology, William Beaumont Hospital, Royal Oak, Michigan, USA
  4. 4Internal Medicine, William Beaumont Hospital, Royal Oak, Michigan, USA
  1. Correspondence to Camilla Cascardo; cascardo{at}


Anti-N-methyl-d-aspartate (NMDA) receptor encephalitis is a progressively debilitating, frequently fatal disease caused by autoantibodies against the NMDA receptor. Risk of delayed treatment is high due to variable presentations, lack of awareness and potential false negative diagnostic studies. In this case report, a woman in her 20s presented with psychiatric manifestations and rapidly declined. Dyskinetic movements and dysautonomia were observed. Initial cerebrospinal fluid and serum anti-NMDA receptor antibodies were negative. MRI was inconclusive. Electroencephalography demonstrated extreme delta brush. Pelvic CT revealed an adnexal teratoma. She remained refractory to treatment until day 126 when, after two cycles of cyclophosphamide, she started to improve. She participated in rehabilitation with eventual discharge home on day 269. Recognising the variable presentations of anti-NMDA receptor encephalitis is important in avoiding misdiagnosis and delayed treatment. If clinical suspicion remains high despite negative results, repeat testing should be pursued. Clinical response should guide treatment decisions in refractory cases.

  • Neurology (drugs and medicines)
  • Epilepsy and seizures
  • Movement disorders (other than Parkinsons)
  • Pathology
  • Therapeutic indications

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  • Contributors CC contributed to reviewing the patient’s chart, drafting the case report, obtaining consent, collecting images and correspondence among authors. AI contributed to reviewing the patient’s chart, obtaining consent and editing the case report. JF contributed to collecting and reviewing pathology images and editing the case report. FD contributed to reviewing the patient’s chart and editing the case report.

  • Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.

  • Case reports provide a valuable learning resource for the scientific community and can indicate areas of interest for future research. They should not be used in isolation to guide treatment choices or public health policy.

  • Competing interests None declared.

  • Provenance and peer review Not commissioned; externally peer reviewed.