Pediatrics & Neonatology
Volume 49, Issue 5 , Pages 201-204, October 2008

Valproate-induced Hyperammonemic Encephalopathy

  • Hsiao-Feng Chou

      Affiliations

    • Department of Pediatrics, Kaohsiung Medical University Hospital, Kaohsiung, Taiwan
    • Department of Pediatrics, Tian-Sheng Memorial Hospital, Pingtung, Taiwan
    • ,
  • Rei-Cheng Yang

      Affiliations

    • Department of Pediatrics, Kaohsiung Medical University Hospital, Kaohsiung, Taiwan
    • ,
  • Cheng Ying Chen

      Affiliations

    • Department of Nephrology, Tian-Sheng Memorial Hospital, Pingtung, Taiwan
    • ,
  • Yuh-Jyh Jong

      Affiliations

    • Department of Pediatrics, Kaohsiung Medical University Hospital, Kaohsiung, Taiwan
    • Department of Laboratory Medicine, Kaohsiung Medical University Hospital, Kaohsiung, Taiwan
    • Graduate Institute of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan
    • Corresponding Author InformationCorresponding author. Department of Pediatrics, Kaoshung Medical University Hospital, 100 Shih-Chuan 1st Road, Kaohsiung 80708, Taiwan

Received 21 May 2008; received in revised form 4 August 2008; accepted 19 September 2008.

Article Outline

Valproate-induced hyperammonemic encephalopathy is an unusual but serious complication that can occur in people with normal liver-associated enzyme levels, and despite normal therapeutic doses and serum levels of valproate. Here, we describe an adolescent girl suffering from absence seizures, who complained of progressive dizziness and general malaise several days after restarting valproate. She developed vomiting and decreased consciousness after 3 weeks of valproate use. She had a serum ammonia level five times higher than the upper normal limit, normal liver-associated enzymes, and a supra-therapeutic valproate level. Electroencephalography (EEG) showed continuous generalized slowing. Tandem mass spectrometry analysis revealed carnitine deficiency. Her consciousness improved after emergent hemodialysis. Her ammonia level and EEG also became normal. Possible mechanisms, risk factors and treatments of valproate-induced hyperammonemic encephalopathy are described. Physicians should consider this possibility when consciousness disturbance occurs in patients treated with valproate.

Key Words:  encephalopathy , hyperammonemia , valproate

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PII: S1875-9572(09)60010-3

doi:10.1016/S1875-9572(09)60010-3

Pediatrics & Neonatology
Volume 49, Issue 5 , Pages 201-204, October 2008

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