Anti-N-methyl D-aspartate receptor encephalitis in childhood.

OBJECTIVE: To discuss the differential diagnosis of encephalitis beyond that of infectious etiology and to inform pediatricians about the possibility of anti-N-methyl-D-aspartate receptor (NMDAr) encephalitis in children by highlighting its most important clinical features. DESCRIPTION: Three patients presented with an initial neuropsychiatric syndrome followed by encephalopathy and movement disorder. The initial neuropsychiatric features which developed over days to weeks included a change in personality, anxiety, confusion, and speech regression. This was followed by a choreoathetoid or dystonic movement disorder affecting the orofacial region and the limbs. After the exclusion of the major causes of encephalitis, NMDAr antibodies were identified in serum and cerebrospinal fluid, and neoplasm screening did not detect any tumor. Patients were submitted to immunosuppression, and two of them had a full neurological recovery. One of them still presents a mild dystonic posture in a limb. COMMENTS: Clinical signs of anti-NMDAr encephalitis in children are similar to those previously described in adults. Tumors are not usually detected by this age. The diagnosis of anti-NMDAr encephalitis must be addressed only after the exclusion of infectious and other recognizable causes of encephalitis. Pediatricians should be aware of this treatable autoimmune condition.