Valproate-Induced Non-Hepatic Hyperammonaemic Encephalopathy: A Rare Complication of Chronic Valproate Therapy

Abstract

Valproic acid can sometimes produce encephalopathy secondary to hyperammonemia without hepatic dysfunction, termed as valproate-induced hyperammonaemic encephalopathy (VHE). VHE is characterized by acute onset of impaired consciousness, lethargy, confusion, headache, vomiting, seizures and focal neurological deficits. Known risk factors include therapy with multiple antiepileptic drugs, presence of underlying inborn errors of metabolism, febrile states, and insufficient nutritional intake. We hereby, describe a case of VHE in a 10-year-old male child on long-term VPA therapy and no history of underlying liver disease. Encephalopathy reversed on withdrawal of VPA and L-carnitine therapy. We emphasize the need for early recognition, investigation, and treatment of this potentially life-threatening condition. doi:10.4021/ijcp33w