A Case of Hyperammonemia and Coma Induced by Sodium Valproate after Hepatectomy for Liver Metastasis

Kazuo Hatsuse, Takashi Hayashi, Takuo Inui, Hideki Aoki, Kenji Tsuboi, Tsukasa Aihara, Syoetsu Tamakuma

First Department of Surgery, National Defense Medical College

A case of hyperammonemia and coma induced by sodium valproate (VPA) after hepatectomy for liver metastasis is reported. A 50-year-old man who suffered from cerebral infarction in the past, had been taking VPA as an anti-convulsant drug. The course after hepatectomy was uneventful, and food intake was begun from the 4th postoperative day with lactulose and VPA. Four days after the interruption of lactulose, he complained of general malaise. Five days after the interruption of lactulose, he fell into coma. Although there were no abnormalities in liver function examinations and brain computed tomography, the ammonia level was so high that we suspected the coma was due to hyperammonemia induced as a possible side effect of the drug. He regained consciousness 2 days after the interruption of VPA and administration of lactulose and morihepamine. Ammonia was high on the preoperative day when VPA was administrated. Ammonia decreased during transient elevation just after the operation when VPA was interrupted, and became elevated with VPA re-administration. Analysis of amino acids revealed a decrease in arginine with VPA administration. The above suggests that coma resulted from inhibition of the urea cycle, which was induced by VPA and hepatectomy.

Key words
valproate, hepatic resection, hyperammonemia

Reprint requests
Kazuo Hatsuse First Department of Surgery, National Defense Medical College
3-2 Namiki, Tokorozawa, 359 JAPAN

Accepted
December 7, 1994

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