A Case of Valproate Induced Hyperammonemic Encephalopathy in an Elderly Bipolar Patient Under Treatment With Sulphonylureas

Abstract

Valproic acid induced hyperammonaemic encephalopathy (VPA-VHE) is a rare side effect of valproic acid. It is characterized by impaired consciousness and lethargy, focal neurological signs or symptoms with a serum level of ammonia above 40 mmol/L. This syndrome is often misdiagnosed, especially in psychiatricsetting.Wepresentthe case of a bipolar patient who developed VPA-VHE. He assumed also sulphonylureas to manage mild hyperglycemia. After three months of treatment with valproic acid patient had a depressive episode and acute onset of headache, disorientation, consciousness impairment, and psychomotor slowing. This presentation induced to make investigation and we have discovered hyperammonaemia with EEG alteration; a diagnosis of valproate induced hyperammonemic encephalopathy (VHE) was made. The patient recovered quickly after discontinuing valproic acid therapy. Valproic acid is a frequent treatment in psychiatricsetting and a betterknowledge of possibleadverseeffectsisimportant to prevent and manage rare conditions like VHE. J Med Cases. 2013;4(8):540-543 doi : http://dx.doi.org/10.4021/jmc1313w