RESUMO
Anti NMDA receptor encephalitis is autoimmune encephalitis where antibodies are directed against NMDA receptor subunit. It represents a new category of immune-mediated disorder that is often paraneoplastic, presenting with neuropsychiatric symptoms, which is treatable and can be diagnosed serologically affecting both children and adults. Patient can have variable clinical presentation ranging from prodromal illness, neuropsychiatric symptoms, seizures, autonomic instability, hyperkinesias, catatonia, hypoventilation and with or without an associated teratoma. A positive serum or CSF sample screening for antibodies to the NMDA receptor subunit is confirmative. Supportive findings include CSF study, EEG and MRI Brain. The first-line therapies includes IVIG, corticosteroids or plasma exchange. Second line immunotherapy is rituximab or cyclophosphamide or both. Given the high mortality rate (up to 25%), the likelihood of presentation across the age range and the potential for treatment, a high index of suspicion is warranted by clinicians. Authors report a case of a 5 year old child with anti NMDA receptor encephalitis who responded well to IVIG therapy.