[Subacute anti-N-methyl-D-aspartate receptor encephalitis. A serie of 13 paediatric cases]

Subacute anti-NMDA receptor encephalitis was recognised in 2007 as a clinical entity, and was first described in young women with ovarian teratoma. The first paediatric series unrelated with tumours was reported in 2009.

To present the clinical features, treatment, and prognosis of 13 patients with anti-NMDA receptor encephalitis in Chile.

A description is presented of 13 children, 9 males, aged between 1 and 16 years, diagnosed between 2009 and 2016 in 7 hospitals. All patients were evaluated with cerebral magnetic resonance and electroencephalogram. Cytochemical, oligoclonal bands and virus studies (PCR and antibodies) were performed in cerebrospinal fluid. All patients were evaluated in search of anti NMDA receptor in serum and cerebrospinal fluid. Tumor imaging studies were performed in all children.

All children began the disease with psychiatric symptoms, and 11/13 had seizures. All of them subsequently presented with psychomotor agitation, dystonia, and bucolingual dyskinesias, with 11/13 loss of language and 6/13 autonomic disorders. All of them (13/13) had positive anti-NMDA receptor antibodies. CSF was normal in 12/13 children, positive oligoclonal bands in 6/10 patients, normal brain resonance in 13/13 children, EEG changes in 11/13 children, and abnormal SPECT in 6/6 children. A methylprednisolone bolus of 30mg/kg was given for 3-5 days to 12/13 children, and 6 received immunoglobulin 2g/kg. The large majority (12/13) of children recovered 1-4 months after disease onset. One child had a recurrence one year later, and recovered quickly.

Subacute encephalitis due to NMDA anti-receptor antibodies should be suspected in children with psychiatric disorders and abnormal movements. Functional studies, such as EEG and SPECT are valuable diagnostic support. Early detection of this encephalitis leads to a faster recovery of patients.