Anti-NMDA receptor encephalitis in a 3-year-old girl with no associated pathology involving a tumour

Encephalitis due to NMDA receptors antibodies is a relatively common condition but it was under diagnosed until recently. It courses predictably and similarly in adults and children, although there are some differences, still less its association with tumours. A 3 years-old girl who was admitted to our hospital with symptoms compatible with acute encephalitis, so we started treatment with acyclovir. During admission she was alterning periods of poor response to stimuli with periods of agitation, and progressed to complete silence, adding sleep problems. She suffered epileptic seizures, dystonic movements and autonomic disturbances. Cranial MRI showed mild cortical atrophy and EEG generalized slowing of base tracing. Repeated samples of cerebral spinal fluid were normal from cytological and biochemical point of view. In view of the torpid evolution she began methylprednisolone therapy and later inmunoglobulins with no improvement. Upon confirmation of the positivity for NMDA receptors antibodies in cerebral spinal fluid and serum, cyclophosphamide was administered, with gradual improvement of symptoms until full recovery. After ten months of follow-up without treatment she has not presented relapses and has ruled out the presence of tumours. CONCLUSIONS. It is important to recognize encephalitis with behavioural changes and abnormal movements, because early diagnosis and the beginning of appropriate therapy could improve the prognosis.