Three phenotypes of anti-N-methyl-D-aspartate receptor antibody encephalitis in children: prevalence of symptoms and prognosis.

BACKGROUND: Anti-N-methyl-d-aspartate (NMDA) receptor antibody encephalitis is becoming an increasingly recognized cause of encephalopathy in individuals previously presumed to have viral encephalitis. Various manifestations of this disease include altered mental status, behavioral changes, seizures, and movement disorders. We have noted three distinct subtypes of this disease which appear to have differential responses to immunotherapies and differences in prognosis. METHODS AND PATIENTS: We report eight patients observed at our children's hospital from 2009 through 2013 who appear to clearly fall into one of our three clinical categories. To find comparable articles reflecting this classification, we then performed a MEDLINE search of all articles involving the subject heading "anti-NMDA receptor encephalitis" or just the keyword phrase "NMDA encephalitis," and we found 162 articles to review. Twenty-two articles were eliminated due to basic science, and we were able to review 105 of the remaining articles, most of which were case reports or case series, although a few were larger reviews. For the sake of our review, we defined type 1 or "classic" anti-NMDA receptor antibody encephalitis as having a duration of <60 days and being characterized predominantly by a catatonic or stuporous state, type 2 or psychiatric-predominant anti-NMDA receptor antibody encephalitis as having no noteworthy catatonic or stuporous state in addition to the presence of predominantly behavioral and psychiatric symptoms, and type 3 or catatonia-predominant anti-NMDA receptor antibody encephalitis as having a duration of ≥60 days in a predominantly catatonic or stuporous state. RESULTS: We note that the poorest responders, even to aggressive immunotherapies, are the patients with catatonia-persistent type anti-NMDA receptor antibody encephalitis, which has, as its hallmark, prolonged periods of severe encephalopathy. Patients with predominantly psychiatric symptoms, which we call the psychiatric-predominant anti-NMDA receptor antibody encephalitis, have had excellent responses to plasma exchange or other immunotherapies and appear to have the least residual deficits at follow-up. Patients with fairly equal representations of periods of altered mental status, behavioral problems, and movement disorders appear to have an intermediate prognosis and likely require early aggressive immunotherapy. CONCLUSIONS: In our series, we discuss representative examples of these clinical subtypes and their associated outcomes, and we suggest that tracking these subtypes in future cases of anti-NMDA receptor antibody encephalitis might lead to better understanding and better risk stratification with regard to immunotherapy decisions.

[Anti-NMDA-receptor encephalitis: a new axis-III disorder in the differential diagnosis of childhood disintegrative disorder, early onset schizophrenia and late onset autism]. / Anti-NMDA-receptorencefalitis: een nieuwe as III-stoornis in de differentiaaldiagnose van desintegratiestoornis van de kinderleeftijd, vroeg optredende schizofrenie en laat optredend autisme.

Childhood disintegrative disorder (CDD), early onset schizophrenia (EOS), and late onset autism (LOA) often follow a similar course: initially, development is normal, then there is a sudden neuropsychiatric deterioration of social interaction and communication skills, which is combined with a decline in intelligence and reduction in daily activities. A 9-year-old boy was admitted to the paediatric ward with acute onset of secondary epileptic seizures. It was not long until the boy's symptoms resembled that of patients with cdd, eos and loa. Intensive tests led to the diagnosis of anti-NMDA-receptor encephalitis. Anti-NMDA-receptor encephalitis should be regarded as a possible organic cause underlying the syndromal presentation of CDD, EOS and LOA.