To report that anti-NMDA receptor encephalitis in children can present as epileptic spasms and developmental regression.

An autoimmune etiology for epileptic spasms is uncommon.  To date, only one case of a 3-month-old girl with anti-NMDA receptor encephalitis who subsequently developed infantile spasms has been reported.  Here we report a second case of a child who presented with neurodevelopmental regression and epileptic spasms due to anti-NMDA receptor encephalitis, who continued to have refractory epilepsy and epileptic encephalopathy despite aggressive treatment.

Retrospective chart review and literature search.

A 19-month-old, previously healthy child presented with a 6-week history of rapidly progressive loss of neurodevelopmental milestones, irritability and dystonic movements. MRI brain showed abnormal T2 signal in the basal ganglia bilaterally. CSF was unremarkable except for the presence of anti-NMDA receptor antibodies. Genetic and paraneoplastic screening were negative. Initial EEG revealed multifocal spikes with delta brush activity. The patient was diagnosed with anti-NMDA receptor encephalitis and was started on IV methylprednisolone, followed by plasma exchange and rituximab. A week later, she developed flexor epileptic spasms. Video EEG showed hypsarrhythmia pattern, with generalized and multifocal spikes. The patient then developed myoclonic and tonic seizures with progressive neurological decline. Her seizures proved refractory to many antiepileptic medications (vigabatrin, valproate, clonazepam, clobazam, rufinamide, cannabidiol), ketogenic diet, immunotherapy (prednisone, IVIG, and rituximab). Six months later, brain MRI showed stable signal abnormality in the basal ganglia with interval increase in brain atrophy. EEG continued to show diffuse slowing, multifocal spikes, and paroxysmal fast activity, consistent with an epileptic encephalopathy.

Anti-NMDA-receptor encephalitis can be rarely be associated with epileptic infantile spasms. While timely intervention and immunotherapy can lead to improved neurological outcomes in older children and adults, further studies are needed to identify optimal treatment in younger patients.