Retrospective analysis of NMDA receptor antibodies in encephalitis of unknown origin

Neurology. 2010 Nov 9;75(19):1735-9. doi: 10.1212/WNL.0b013e3181fc2a06.


Background: Anti-NMDA-receptor (NMDAR) encephalitis is a severe disorder that occurs in association with antibodies to the NR1 subunit of the NMDAR and results in a characteristic syndrome.

Objective: To determine in a single institution setting whether patients previously diagnosed with encephalitis of unknown origin had anti-NMDAR encephalitis.

Methods: Charts of 505 patients aged 18 to 35 years admitted to the intensive care unit (ICU) during a 5-year period were retrospectively reviewed for criteria of encephalitis of unknown etiology. These included encephalitic signs with psychiatric symptoms (agitation, paranoid thoughts, irritability, or hallucinations); seizures; CSF inflammation; and exclusion of viral or bacterial infection. Archived serum and CSF samples of patients fulfilling these criteria were examined for NMDAR antibodies. Follow-up visits allowed the analysis of the natural disease course and estimation of prognosis.

Results: Seven patients (all women) fulfilled the indicated criteria; 6 of them had NMDAR antibodies. Ovarian teratomas were detected in 2 patients, in one 3 years after the onset of encephalitis. Outcome was favorable in all patients. One patient without teratoma improved spontaneously along with disappearance of NMDAR antibodies.

Conclusions: Anti-NMDAR encephalitis represented 1% of all young patients' admissions to the ICU. Six of 7 cases with the indicated clinical criteria had anti-NMDAR encephalitis. NMDAR antibodies should be tested in all patients with encephalitis who fulfill these criteria.

Publication types

  • Comparative Study

MeSH terms

  • Adolescent
  • Adult
  • Autoantibodies / biosynthesis*
  • Autoantibodies / blood
  • Cell Line
  • Encephalitis / diagnosis*
  • Encephalitis / immunology*
  • Encephalitis / metabolism
  • Female
  • Follow-Up Studies
  • Humans
  • Receptors, N-Methyl-D-Aspartate / immunology*
  • Retrospective Studies
  • Young Adult


  • Autoantibodies
  • NR1 NMDA receptor
  • NR2A NMDA receptor
  • Receptors, N-Methyl-D-Aspartate