Pediatric N-Methyl-d-Aspartate (NMDA) Receptor Encephalitis, With and Without Herpes Encephalitis.

OBJECTIVE

To compare clinical, diagnostic, management, and outcome factors in children with anti-N-methyl-d-aspartate receptor (NMDAR) encephalitis and a history of herpes simplex encephalitis (HSE) to children with NMDAR encephalitis without a history of HSE.

METHODS

All patients with anti-NMDAR antibodies in cerebrospinal fluid treated at our institution between 2012 and 2019 were identified and divided into those with a history of HSE (HSE+NMDAR group) and those without a history of HSE (NMDAR-only group). Demographic data, clinical characteristics, immunotherapy, and outcome data were collected on all patients and compared between the 2 groups.

RESULTS

Seventeen patients were identified with anti-NMDAR antibodies in cerebrospinal fluid, 6 of whom had a history of HSE. Mean age in the HSE+NMDAR cohort was significantly younger in the HSE+NMDAR cohort, as 5 of the 6 patients were infants. Of HSE+NMDAR patients, 50% had behavioral symptoms, 67% had movement disorders, and 100% had seizures at disease nadir. In the NMDAR-only group, 100% had behavioral symptoms, 73% had movement disorders, and 73% had seizures at nadir. HSE+NMDAR patients received a median of 1 immunotherapy, compared to a median of 4.5 immunotherapies in the NMDAR-only group.

CONCLUSION

Behavioral symptoms were more common in NMDAR-only patients, whereas seizures were more common in HSE+NMDAR patients. Both groups had significant disability at disease nadir, with more improvement in disability over time in the NMDAR-only group. HSE+NMDAR patients received fewer immunotherapies than NMDAR-only patients. Outcomes of infants with HSE appear to primarily reflect sequelae from HSE.