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anti-NMDA receptor encephalitis; NMDAR Ab encephalitis

Etiology: - associated with anti-NMDA receptor antibodies - most commonly associated with bilateral ovarian teratoma Epidemiology: - 80% women - most commonly occurs age 2-40 years [4] Pathology: - antibody against NMDA receptor (cell surface receptor) - neurons expressing this receptor remain intact [4] Clinical manifestations: 1) onset may be heralded by flu-like syndrome - gastrointestinal symptoms: nausea 2) evolution over weeks to months 3) altered mental status a) subacute memory distubance, short term memory loss [4] b) personality changes c) agitation [4], delirium [4] d) psychosis - auditory hallucinations & visual hallucinations [4] e) photophonophobia 4) choreoathetosis [1] - intermittent muscle rigidity - involuntary jerking movements of the arms & legs [4] 5) seizures [2] 6) autonomic instability [1] - palpitations, sinus tachycardia - intermittent fever - hypertension 7) no focal neurologic deficits, no nuchal rigidity [4] Laboratory: - CSF analysis - normal or mild CSF lymphocyte pleocytosis - normal or mildly elevated CSF protein - anti-NMDA receptor antibody in CSF & serum Special laboratory: - pelvic ultrasound for ovarian teratoma - ovarian teratomas implicated in NMDAR Ab encephalitis Radiology: - neuroimaging - MRI may show FLAIR signals in one or both temporal lobes Differential diagnosis: - Herpes simplex encephalitis - anti-leucine-rich glioma inactivated 1 encephalitis Management: 1) empiric IV acyclovir for Herpes simplex encephalitis until diagnosis is clarified [1] - IV vancomycin, ceftriaxone, & acyclovir used in ref [4] 2) ovariectomy if teratoma; full remission has resulted [4] 3) immunosuppressive therapy: - combination of plasmapheresis, intravenous gamma-globulin & glucocorticoids [4] - addition of rituximab or cyclophosphamide reserved for refractory cases [4] Prognosis: - full recovery after surgical removal of teratoma may take months [4] - 75% of patients recover either completely or substantially [4]

Related

anti-NMDA receptor antibody NMDA receptor

General

paraneoplastic limbic encephalitis paraneoplastic encephalomyelitis sensory neuropathy

References

  1. Medical Knowledge Self Assessment Program (MKSAP) 16, 17, 18. American College of Physicians, Philadelphia 2012, 2015, 2018.
  2. Dalmau J, Gleichman AJ, Hughes EG et al Anti-NMDA-receptor encephalitis: case series and analysis of the effects of antibodies. Lancet Neurol. 2008 Dec;7(12):1091-8 PMID: 18851928
  3. Titulaer MJ, McCracken L, Gabilondo I et al Treatment and prognostic factors for long-term outcome in patients with anti-NMDA receptor encephalitis: an observational cohort study. Lancet Neurol. 2013 Feb;12(2):157-65. PMID: 23290630 Free PMC Article
  4. Mathai SK, Josephson SA, Badlam J et al Scratching Below the Surface. N Engl J Med 2016; 375:2188-2193. December 1, 2016 PMID: 27959764 http://www.nejm.org/doi/full/10.1056/NEJMcps1603154
  5. Dalmau J, Graus F. Antibody-Mediated Encephalitis. N Engl J Med. 2018 Mar 1;378(9):840-851. PMID: 29490181
  6. ARUP Consult: N-methyl-D-Aspartate (NMDA) type Glutamate Receptor Autoantibody Disorders Anti-NMDA-Receptor Encephalitis The Physician's Guide to Laboratory Test Selection & Interpretation https://www.arupconsult.com/content/n-methyl-d-aspartate-nmda-type-glutamate-receptor-autoantibody-disorders - Anti-NMDA Receptor (NR1) IgG Antibodies https://arupconsult.com/ati/anti-nmda-receptor-nr1-igg-antibodies