Childhood Anti-NMDA Receptor Encephalitis.

OBJECTIVES: To study the clinical profile, and outcome of children with anti-N-methyl-D-aspartate receptor (NMDAR) encephalitis.

METHODS: This is a retrospective case series of children <12 y of age, diagnosed with anti-NMDAR encephalitis at a tertiary care institute during the period, May 2013 through June 2015.

RESULTS: Twenty patients were tested for suspected anti-NMDAR encephalitis over this 2 y period. Of these, six children were positive for anti-NMDAR antibodies. Four of these six children had completed treatment and two are currently receiving immunotherapy. Behavioral changes, psychosis, seizures and oro-lingual-facial dyskinesia were the presenting features. Extreme irritability, insomnia and mutism were noted in all the children. The symptoms were persistent, and the course was progressive over 4-8 wk duration. Neuroimaging and electroencephalography were non-specific. Intravenous pulse methylprednisolone and immunoglobulins were used as first-line therapeutic agents. Only one patient responded to first line immunotherapy; five out of six children required second-line immunotherapy. One patient recovered following rituximab, and two patients showed a good response to cyclophosphamide pulse therapy; two patients are currently under treatment with second line immunotherapeutic agents. Tumor screen was negative in all children.

CONCLUSIONS: Anti-NMDAR encephalitis is rare but a potentially treatable condition. Timely recognition is essential because treatment is entirely different from other viral encephalitis. Aggressive immunotherapy is the key to a favourable outcome.