Neuroleptic Malignant Syndrome in a Boy with NMDA Receptor Encephalitis

Abstract

Chief Complaint and Presenting ProblemM . is an 11-year-old African American boy who was referred to the psychiatry consult liaison service eight days after admission to an epilepsy monitoring unit for behavioral disruption and inability to sleep. History of Present IllnessParents reported that M. had been a normally developing fifth grader who did well in school. M. developed the sudden onset of seizures six weeks prior to admission; his family found him curled in a fetal position with irregular jerking movements. Parents transported him to the emergency department, and an EEG demonstrated absence seizures. M. was hospitalized for several days, treated with valproic acid, and then discharged to outpatient followup. During this admission, M. was evaluated by the psychiatry team for anxiety, as he had expressed fear that he was going to die as a result of his illness. He also endorsed auditory hallucinations of hearing voices, at one point telling him to have more seizures. Outpatient psychotherapy was recommended.In the following six weeks, M. had no identified seizures but experienced many new symptoms. M.'s attention, concentration, and academic performance declined dramatically, according to his teachers. He had multiple crying fits and mood swings each day. M. became increasingly somnolent, but had difficulty sleeping each night and began to slur his speech. Teachers recommended an Individualized Education Plan one month prior to referral due to his significant academic decline.One day prior to admission, M. presented to the emergency department with four absence seizures, and was loaded with valproic acid and discharged. On the day of admission, M. again presented to the emergency department with two brief absence seizures culminating in a generalized tonic-clonic seizure that lasted 30 minutes and required intravenous midazolam. M.'s serum valproic acid level was 126 (therapeutic range 50-100 ug/mL) and ammonia was 102 (normal range 11-35 uM/L). His presumptive diagnosis was hyperammonemia due to valproic acid toxicity, and he was admitted.Following admission, M. experienced episodes of dystonic posturing and nystagmus, only some of which were associated with epileptiform activity on long-term electroencephalogram (EEG) monitoring. His EEG consistently showed diffuse delta wave slowing. At the time of psychiatry consultation, M. was in full upper-extremity restraints due to agitation, and his verbal capacity had regressed to repeating the same word or phrase, often speaking in unintelligible sounds entirely. He followed commands inconsistently, and had not slept more than three hours a night in over a week. M. was given 0.3 mg of risperidone for agitation the night before psychiatry consultation. Psychiatry consultation was requested to further advise on medication management.After extensive assessment, psychiatry concluded that M. had suffered a grand mal seizure of unknown etiology and had recent cognitive decline consistent with delirium. In addition to continuing the extensive workup already underway, t...

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