Clinical Features of Children With Anti-N-Methyl-D-Aspartate Receptor Encephalitis Following Viral Encephalitis.

Background: Anti-N-methyl-D-aspartate receptor encephalitis (anti-NMDARE) can occur after herpes simplex encephalitis (HSE) and Japanese encephalitis (JE). We describe the clinical features of children with anti-NMDARE after viral encephalitis.

Objective: This study aims to describe the clinical characteristics, laboratory findings, and treatment outcomes of these patients.

Methods: We describe the clinical characteristics of 14 children of anti-NMDARE following viral encephalitis treated at National Children's Hospital from January 2021 to December 2022. Patients with evidence of viral reactivation or other antibodies were excluded.

Results: There are 12 children with anti-NMDARE after HSE and 2 children after JE. The median age was 2.1 years (range 0.6-12.9), with 8 male patients. All patients (100%) had fever and seizures, while 50% exhibited focal neurological signs. No patients experienced movement disorders, psychiatric symptoms, or sleep disturbances during the viral encephalitis phase. In contrast, the most common symptoms during the anti-NMDARE phase were as follows: movement disorders in 92.9% (13/14), recurrent or prolonged fever in 71.4% (10/14), sleep disturbances in 64.3% (9/14), seizures in 50% (7/14), and psychiatric symptoms in 50% (7/14). The median cerebrospinal fluid (CSF) white blood cell count in the viral encephalitis and anti-NMDARE phases was 57 (4-410) and 13 (2-48), respectively. The mean CSF protein concentration was 0.43 ± 0.16 g/L and 0.85 ± 0.63 g/L, respectively. Brain MRI was performed in both encephalitis phases for 10/14 patients, with 8/10 showing no new lesions.

Conclusion: There were differences in clinical symptoms and CSF findings between the two phases of encephalitis; however, most patients did not develop new lesions on brain MRI.