Background Anti-NMDA-receptor encephalitis is the most common and best characterized antibody-mediated encephalitis. We provide the clinical features, treatment, and follow-up of 500 patients.
Design/Methods: Cohort study, analysis of demographics, onset, treatment, and long-term follow-up.
Results: 82% were female. Median age was 21 years (range 1-85; 36% <18 and 4% >45 years). 42% had a tumor (95% teratomas). 55% of females >12 years had ovarian teratoma(s) versus 8% <12 years. In patients <12 years old the most frequent initial symptoms were abnormal behavior, seizures, and movement disorders (36%, 35%, 14%), while in adults were abnormal behavior and memory problems (70%, 13%). 90% of patients had >3 of the following: psychiatric symptoms, memory, speech disorders, seizures, dyskinesias, decreased level of consciousness, autonomic instability, or hypoventilation. Within the first month, movement disorders and ataxia were more frequent in children (92% and 17% vs 70% and 2%, p<0.001 both), while memory problems and hypoventilation predominated in adults (84% and 42% vs 68% and 16%,p=0.008 and p<0.001). Immunotherapy (93%) and tumor removal (when appropriate) resulted in full recovery or substantial improvement in 61% of patients at 8 months, and 77% at 24 month follow-up; 7% died. Early treatment (1st month) led to better outcome (75% vs 64%, p=0.001). If 1st line immunotherapy (steroids, immunoglobulins and/or plasma exchange) failed, 2nd line treatment (rituximab or cyclophosphamide) significantly improved outcome compared with no treatment or repeating 1st line drugs (56% vs 27%,p=0.006). Relapses occurred in 14%, 73% of them in patients without teratoma.
Conclusions: Anti-NMDA-receptor encephalitis is a severe but treatable disorder of predominantly young individuals. Prompt treatment improves outcome. If initial immunotherapy fails, second-line treatment is usually effective. 75% of patients have full/substantial improvement although the process of recovery can take >24 months.
