Retrospective analysis of NMDA receptor antibodies in encephalitis of unknown origin.
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.
Charité University Medicine Berlin, Department of Neurology, Charitéplatz 1, 10117 Berlin, Germany. harald.pruess@charite.de
H
H
Prüss
J
J
Dalmau
L
L
Harms
M
M
Höltje
G
G
Ahnert-Hilger
K
K
Borowski
W
W
Stoecker
K P
KP
Wandinger
D000293:Adolescent; D000328:Adult; D001323:Autoantibodies / Q000096:biosynthesis* / Q000097:blood; D002460:Cell Line; D004660:Encephalitis / Q000175:diagnosis* / Q000276:immunology* / Q000378:metabolism; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D016194:Receptors, N-Methyl-D-Aspartate / Q000276:immunology*; D012189:Retrospective Studies; D055815:Young Adult
D001323:Autoantibodies; C409466:NR1 NMDA receptor; C120997:NR2A NMDA receptor; D016194:Receptors, N-Methyl-D-Aspartate