Anti –NMDA receptor encephalitis in children: A study from Eastern India

Introduction: Anti-N-methyl-d-aspartate receptor (Anti-NMDAr) encephalitis is the second common cause of autoimmune encephalitis.

Objectives: To describe the clinico-epidemiological profile, treatment, and outcome of paediatric anti-NMDAr encephalitis patients.

Method: This is a retrospective, observational study in a tertiary care hospital from eastern India with 16 anti-NMDAr encephalitis cases aged <12 years. All patients were positive for cerebrospinal fluid (CSF) anti NMDAr antibody. Graus criteria were used for case detection and modified Rankin scale for assessing neurological disability before and after treatment. All cases received first line immunotherapy with intravenous immunoglobulin (IVIG), methyl prednisolone or both; those with failure to respond or worsening were considered for second line immunotherapy.

Results:  The 16 patients were aged 6 months to 11 years (mean 7.7 years); 43.8% were female; they were diagnosed by an average 25 days; speech defects (93.8%), psychiatric manifestations (100%) and seizures (87.5%) were the early features. CSF anti NMDAr antibody was positive in 100% and electro-encephalographic (EEG) changes were found in 100%. There were no tumours in pelvis or abdomen on ultrasonography. Magnetic resonance imaging abnormalities were present in 62.5%. First line immunotherapy consisting of only IVIG (18.8%), only methyl prednisolone (6.25%) and both IVIG and methyl prednisolone (75%) was started by a median 30 days, with better response in the latter group. Seven (43.8%) patients received second line immunotherapy (Rituximab) with prompt response

Twelve (75%) cases are under regular follow up. Oral prednisolone was continued for one year in the initial 8 cases. In the remaining 4 cases, steroids were tapered when serum anti NMDAr antibody became negative. Relapse was noted in one case.

Conclusions: Speech defects (93.8%), psychiatric manifestations (100%) and seizures (87.5%) were early features. Positive CSF anti NMDAr antibody and EEG changes were found in 100%. First line immunotherapy consisted of IVIG and methyl prednisolone.

Sri Lanka Journal of Child Health, 2022; 51(4): 513-518