A pediatric case of anti-N-methyl-D-aspartate receptor encephalitis with unilateral seizure, hemiplegia, and gait disorder who required a long time for diagnosis

Abstract

  We report a case of anti-N-methyl-D-aspartate (NMDA) receptor encephalitis in a 2-year-old boy. He presented with frequent partial seizures in the left side of his body with no preceding infection or fever, followed by mild left-side hemiplegia and gait disturbance. During the course of the seizure, stereotypic, lip licking movement of the tongue was observed. Also, he developed irritability and night delirium at the eleventh day from the onset. Initially, he was treated as epilepsy and received an anti-epileptic drug because his level of consciousness in the daytime was normal and his magnetic resonance imaging scan revealed no abnormalities. Eighteen days later, he presented with status epilepticus, accompanied by persisting impaired consciousness. He received methylprednisolone pulse therapy, high-dose immunoglobulin therapy, and thyrotropin-releasing hormone therapy. Although hemiplegia resolved and no motor sequela was observed, higher brain dysfunction remained. With identification of anti-NMDA receptor antibody, he was diagnosed with anti-NMDA receptor encephalitis 2 months after the initiation of symptoms. Adult patients of anti-NMDA receptor encephalitis often show psychiatric symptoms initially. However, in case of pediatric patients, seizure and involuntary movement are reported as initial symptoms. Although in retrospect, the clinical course of our patient was typical of pediatric anti-NMDA receptor encephalitis, it was not easy to reach the final diagnosis. We suggest that proper knowledge of disease characteristics of pediatric anti-NMDA receptor encephalitis is essential for early diagnosis and treatment. Also, clinical diagnostic criteria that do not rely on time-consuming antibody testing are suggested. Applying such criteria to pediatric cases might be beneficial for early diagnosis.