We report the case of a patient with schizophrenia who presented to the emergency department (ED) with a mental status change. He was initially treated for nonconvulsive seizures until a valproic acid (VPA) serum concentration test was performed and indicated acute intoxication.

To report a case of acute intoxication with VPA that was unrecognized and treated as nonconvulsive seizure.

A 28-year old man presented to the ED after being assaulted. A computed tomography scan of his head showed no intracranial injury. While still in the ED, the patient became increasingly difficult to arouse. Because nonconvulsive seizures were suspected, an electroencephalogram was performed, which indicated mild encephalopathy but no epileptogenic activity. Despite these results, the patient was given VPA 1000 mg intravenously. A VPA level was obtained before the dose was given, but the results were not available at the time the dose was ordered and administered. It was later determined to be greater than 300 μg/mL and increased to 423 μg/mL. The patient was admitted to the hospital and later reported that he had attempted to commit suicide by taking an unknown amount of VPA, which was prescribed for a history of schizophrenia.

Emergency physicians should be aware that anticonvulsant medications are used for a variety of medical conditions in addition to the treatment of seizure disorders. Especially when anticonvulsant medications are used for psychiatric conditions, acute intoxication should be a differential diagnosis in any patient presenting with mental status changes.