Objective: To report the clinical features of anti-N-methyl-D-aspartate receptor (NMDAR) encephalitis in patients Յ 18 years old. Methods: Information was obtained by the authors or referring physicians. Antibodies were determined by immunocytochemistry and enzyme-linked immunosorbent assay (ELISA) using HEK293 cells ectopically expressing NR1. Results: Over an 8-month period, 81 patients (12 male) with anti-NMDAR encephalitis were identified. Thirty-two (40%) were Յ18 years old (youngest 23 months, median 14 years); 6 were male. The frequency of ovarian teratomas was 56% in women Ͼ18 years old, 31% in girls Յ18 years old ( p ϭ 0.05), and 9% in girls Յ14 years old ( p ϭ 0.008). None of the male patients had tumors. Of 32 patients Յ18 years old, 87.5% presented with behavioral or personality change, sometimes associated with seizures and frequent sleep dysfunction; 9.5% with dyskinesias or dystonia; and 3% with speech reduction. On admission, 53% had severe speech deficits. Eventually, 77% developed seizures, 84% stereotyped movements, 86% autonomic instability, and 23% hypoventilation. Responses to immunotherapy were slow and variable. Overall, 74% had full or substantial recovery after immunotherapy or tumor removal. Neurological relapses occurred in 25%. At the last follow-up, full recovery occurred more frequently in patients who had a teratoma that was removed (5/8) than in those without a teratoma (4/23; p ϭ 0.03). Interpretation: Anti-NMDAR encephalitis is increasingly recognized in children, comprising 40% of all cases. Younger patients are less likely to have tumors. Behavioral and speech problems, seizures, and abnormal movements are common early symptoms. The phenotype resembles that of the adults, although dysautonomia and hypoventilation are less frequent or severe in children.Ann Neurol 2009;66:11-18 Anti-N-methyl-D-aspartate receptor (NMDAR) encephalitis is a recently described disorder with a well defined set of clinical features.1 The associated syndrome has been characterized in adults, frequently young women with teratomas of the ovary who develop changes of mood, behavior, and personality, resembling acute psychosis. The clinical picture usually progresses to include seizures, decreased level of consciousness, dyskinesias, autonomic instability, and hypoventilation.2-5 Despite the severity of the disorder, patients often improve with immunotherapy and removal of the teratoma. 1,3,6 These findings and the discovery that all patients have serum and cerebrospinal fluid (CSF) antibodies that react with the cell surface of neurons suggested an immune-mediated pathogenesis. 1,7,8 Further studies demonstrated that the target antigen of patients' antibodies was the NR1 subunit of the NMDAR. Additionally, application of antibodies into cultures of hippocampal neurons resulted in a significant decrease of postsynaptic NMDAR clusters that was reversed after antibody removal. 9 A recent series of 100 patients showed that the disorder also occurs in patients without teratoma, and that men and children c...

We report a 23-year-old with complex partial status epilepticus, possibly related to underlying stroke-like migraine attacks after radiation therapy syndrome, that was refractory to benzodiazepines and phenytoin but was terminated by administration of intravenous levetiracetam.

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