Abstract
Objective: (1) To describe the clinical and paraclinical characteristics of anti-N-methyl-D-aspartate receptor (anti-NMDAR) encephalitis in children. (2) To evaluate the treatment outcomes of pediatric patients with anti-NMDAR encephalitis. Methods: A cross-sectional descriptive study was conducted on consecutive pediatric patients diagnosed with anti-NMDAR encephalitis at the Vietnam National Children's Hospital between January 2019 and August 2021. Results: All 71 patients had positive cerebrospinal fluid (CSF) anti-NMDAR antibody tests. Secondary anti-NMDAR encephalitis following viral encephalitis occurred in 10 patients, including six cases after herpes simplex encephalitis and three cases after Japanese encephalitis. The median age of the 71 patients was 6 years, with a female-to-male ratio of 1.2:1. Among the 61 patients without a prior history of viral encephalitis, seizures were the initial presenting symptom in 45.9%. At diagnosis, the most common clinical and paraclinical findings in these 61 patients were behavioral disturbances (93.4%), mood disorders (68.9%), sleep disturbances (75.4%), movement disorders (52.5%), language impairment (47.5%), impaired consciousness (77.0%), abnormal background activity on electroencephalography (93.5%), cerebrospinal fluid abnormalities (pleocytosis and/or elevated protein concentration) (70.0%), and abnormal brain magnetic resonance imaging findings (24.6%). Ovarian teratomas were identified in two female patients. Among the 10 patients with secondary anti-NMDAR encephalitis following viral encephalitis, the newly developed manifestations most frequently included movement disorders (8/10), recurrent or persistent fever (5/10), and impaired consciousness (5/10). The mean interval between the onset of viral encephalitis and the development of secondary autoimmune encephalitis was 22.3 ± 8.8 days. Regarding immunotherapy, 18 of 71 patients (25.4%) received corticosteroid monotherapy, 52 of 71 (73.2%) received combined corticosteroids and intravenous immunoglobulin (IVIG), and 13 of 71 (18.3%) were treated with rituximab after an inadequate response to corticosteroids and IVIG. At the end of the study, 58 of 71 patients (81.7%) achieved a favorable outcome (modified Rankin Scale score ≤2), two patients (2.8%) died, and three patients (4.2%) experienced disease relapse. Conclusions: Anti-NMDAR encephalitis in children presents with a broad spectrum of clinical manifestations, with psychiatric symptoms being particularly common at diagnosis. The disease may occur as a secondary autoimmune encephalitis following herpes simplex virus or Japanese encephalitis virus infection, while associated tumors are uncommon in the pediatric population. Immunotherapy is associated with favorable clinical outcomes.
