Eleven month old Child presented with developmental regression, dystonia and stereotypies following a febrile illness. His development was appropriate for his age prior to onset of illness. He had high grade fever for which he was treated at another hospital and improved in a few days. Two weeks later, he developed regression of milestones. He lost neck control and was unable to sit even with support. He was could only make incomprehensible sounds and social smile was lost. Two weeks into the illness, he developed excessive movements of both upper and lower limbs and irritability and restlessness. He developed repetitive movements of both upper limbs in the form of thrusting of hands into the mouth and involuntary movements of neck in the form of backward bending. He did not have seizures, altered sensorium or paucity of movements in limbs. There was no vomiting. His visual tracking was preserved, turned head to sounds. He did not have any other medical illness and there was no family history of neurological illness.

Brain imaging was normal while EEG showed background slowing and spikes. Investigations for metabolic cause was non-contributory. Serum and CSF NMDA receptor antibody were strongly positive. He was treated with intravenous immunoglobulin and monthly pulsed intravenous methylprednisolone. He improved significantly and at last follow up (at the age of two years), he improved completely.