A 5-year-old girl with anti-N-methyl-D-aspartate (NMDA) receptor encephalitis and near-complete recovery following early diagnosis and treatment with immune globulin and steroids is reported from Indiana University, University of Pennsylvania, and Mayo Clinic. She presented with episodic headache, paresthesias and weakness of left hand, agitation, and slurred speech. CT scan, MRI, and video-EEG were initially normal. Symptoms rapidly progressed with choreoathetoid movements, urinary incontinence, mutism, rhythmic tongue thrusting, and dysphagia. EEG on day 3 showed bilateral slowing and occipital epileptiform discharges. Methylprednisolone (IV, 40 mg/kg/day) for 4 days was followed by improvement that plateaued. IV Octagam (0.4 g/kg/day) was given for 5 days, and oral steroids were tapered over 12 weeks. At 5-week follow-up, recovery was almost complete. Immunohistochemical analysis (Mayo Clinic) of CSF obtained on admission revealed anti-NMDA antibodies, with molecular confirmation at University of Pennsylvania. Pelvic MRI was unremarkable, but close observation was advised to rule out relapse and occult ovarian teratoma. [1]

COMMENT. Specific antibody detection is indicated in young children presenting with acute psychiatric and movement disorders such as agitation and dyskinesias. Ovarian teratoma associated with NMDAR encephalitis in young female adults is uncommon in children, but pelvic imaging (MRI) is important since surgical removal of a tumor is followed by rapid recovery. See Ped Neur Briefs Jan 2010;24:1-2, for reports of NMDAR and dyskinetic encephalitis lethargica [2]. In the above case report, pelvic MRI was negative, but the authors recommend close surveillance. They credit the favorable outcome to early initiation of immunosuppressant therapy.