Clinical characteristics of antiNmethylaspartate receptor encephalitis in children.

Objectives: To analyze the clinical characteristics and prognosis of children with anti-N-methyl--aspartate receptor (NMDAR) encephalitis and to provide a basis for early clinical identification of this disease.

Methods: The clinical data of 42 cases of anti-NMDAR encephalitis at Department of Pediatrics, Second Xiangya Hospital, Central South University from January 2015 to March 2018 were collected. The clinical features and followed-up outcomes were analyzed retrospectively.

Results: There were 15 cases (35.7%) of males and 27 cases (64.3%) of females in 42 children, with a ratio of 1꞉1.8. They were aged from 4 months to 17 years, with an average of (9.20±4.66) years. The most common initial symptoms were seizures (47.6%, 20/42) and mental behavior disorder (35.7%, 15/42). During the course of the disease, 85.7% patients(36/42) had mental and behavior disorder, 85.7% patients (36/42) had epilepsy, 76.2% (32/42) had speech disorder, 66.7% patients (28/42) had dyskinesia, 66.7% patients (28/42) had the decreased level of consciousness, 61.9% patients (26/42) had autonomic instability, and 57.1% (24/42) patients had sleep disorder. All the children had positive antibody against NMDA receptor resistance encephalitis in cerebrospinal fluid. Head MRI showed the abnormal incidence was 50.0% (21/42), and the lesions involved in parietal lobe, frontal lobe, temporal lobe, occipital lobe, midbrain, thalamus, basal ganglia and optic nerve. There was a patient with optic nerve damage combined with myelin oligodendrocyte glycoprotein (MOG) antibody positive. Forty cases were examined by electroencephalogram (EEG), 92.5% cases (37/40) were abnormal, mainly showing diffuse slow waves, and δ brushes could be seen in severe cases. And there was 1 patient (2.4%) complicated with mesenteric teratoma. The mRS score (2.14±1.46) at discharge was significantly lower than the highest mRS score (3.88±1.38) during hospitalization (<0.05). After 3-39 months of follow-up, mRS score at 3 months after discharge was only 0.81±1.29, which was still improved compared with that at discharge, 76.2% cases (32/42) experienced complete or near-complete recovery (mRS score≤2), and 4.8% (2/42) cases relapsed. There was no mortality; the initial time of immunotherapy and the highest mRS score in the course of the disease were the factors affecting the prognosis. The earlier the starting time for immunotherapy and the lower mRS score in the course of the disease were, the better the prognosis was.

Conclusions: Seizures, mental and behavior disorder, dyskinesias, speech disorder and autonomic instability are common clinical manifestations of anti-NMDAR encephalitis in children. The effect of immunotherapy is significant, and the time to start immunotherapy and the severity of the disease are important factors affecting the prognosis. Anti-NMDAR encephalitis can be combined with other autoantibodies, but its clinical significance and mechanism need further study.