Rinsho Shinkeigaku (Clinical Neurology)

Case Report

Valproic acid-induced hyperammonemic encephalopathy in a patient receiving valproic acid monotherapy

Hidetada Yamada, M.D.1), Takeo Shishido, M.D., Ph.D.2), Tomoya Mukai, M.D., Ph.D.1), Mutsuko Araki, M.D.1), Hiromitsu Naka, M.D., Ph.D.1) and Hiroshi Tokinobu, M.D.1)

1)Department of Neurology, Hiroshima Prefectural Hospital
2)Department of Neurology, Hiroshima University Hospital

A 79-year-old female was diagnosed with epilepsy because she experienced loss of consciousness twice in January and February and then had a seizure in June 2016. She was treated with 800 mg sodium valproate (sustained release). After 3 days, she experienced loss of appetite, and more than 3 days later, disturbance of consciousness. Serum valproic acid (VPA) concentration was 128.3 µg/ml and serum ammonia was 404 µmol/l. Cerebral edema and status epilepticus occurred. Severe neurological dysfunction remained, even after treatment with continuous hemodiafiltration and levocarnitine. VPA is widely used for the treatment of generalized epilepsy. VPA-induced hyperammonemic encephalopathy is a rare but serious adverse event of VPA. Thus, we must pay attention to serum ammonia levels when using VPA, even VPA monotherapy.
Full Text of this Article in Japanese PDF (754K)

(CLINICA NEUROL, 59: 258|263, 2019)
key words: valproic acid-induced hyperammonemic encephalopathy, hyperammonemia, drug-induced carnitine deficiency

(Received: 28-Nov-18)