A Case of Valproate-Induced Hyperammonemic Encephalopathy / 신경정신의학

ABSTRACT

The authors report a case of a 45-year-old man who developed stupor and hyperammonemia during pharmacological therapy with valproate for bipolar affective disorder. He was found to have a significantly elevated ammonia level (>400 microgram/dl) without any signs of hepatic insufficiency such as hepatic failure. The patient showed severely increased serum ammonia level, but the serum valproate level was within the therapeutic range. And he didn't use any other mood stabilizer and have any risk factors for hyperammonemia such as hepatic dysfunction and metabolic abnormality. The authors conclude that the mental change and hyperammonemia in this case are attributable to valproate medication. The authors also reviewed current literatures on hyperammonemia caused by valproate therapy and treatment with carnitine. Clinicians should be cautious about the potential risk for hyperammonemic encephalopathy caused by valproate medication, and patients who are treated with valproate need to be monitored for blood level of ammonia, especially in the case which shows characteristic mental and/or behavioral change.