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Valproate-related hyperammonemic encephalopathy with generalized suppression EEG: a case report

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Abstract    

Background

Valproic acid (VPA) is a prevalent antiseizure medication (ASM) used to treat epilepsy. Valproate-related hyperammonemic encephalopathy (VHE) is a type of encephalopathy that can occur during neurocritical situations. In VHE, the electroencephalogram (EEG) displays diffuse slow waves or periodic waves, and there is no generalized suppression pattern.

Case presentation

We present a case of a 29-year-old female with a history of epilepsy who was admitted for convulsive status epilepticus (CSE), which was controlled by intravenous VPA, as well as oral VPA and phenytoin. The patient did not experience further convulsions but instead developed impaired consciousness. Continuous EEG monitoring revealed a generalized suppression pattern, and the patient was unresponsive. The patient’s blood ammonia level was significantly elevated at 386.8 μmol/L, indicating VHE. Additionally, the patient’s serum VPA level was 58.37 μg/ml (normal range: 50–100 μg/ml). After stopping VPA and phenytoin and transitioning to oxcarbazepine for anti-seizure and symptomatic treatment, the patient’s EEG gradually returned to normal, and her consciousness was fully restored.

Discussion

VHE can cause the EEG to display a generalized suppression pattern. It is crucial to recognize this specific situation and not to infer a poor prognosis based on this EEG pattern.

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Funding

This study was funded by KuanRen Outstanding Young Talent Program of the Second.

Affiliated Hospital of Chongqing Medical University (KY2019Y006).

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Authors and Affiliations

  1. The Second Affiliated Hospital of Chongqing Medical University, Chongqing, China

    Xianyun Liu & Xi Peng

Authors
  1. Xianyun Liu
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  2. Xi Peng
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Contributions

XP provided the ideas and revised the manuscript. XL searched and reviewed articles related to valproate-related hyperammonemic encephalopathy and malignant EEG patterns, summarized the views, and wrote the manuscript. Both authors read and approved the final manuscript.

Corresponding author

Correspondence to Xi Peng.

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Liu, X., Peng, X. Valproate-related hyperammonemic encephalopathy with generalized suppression EEG: a case report. Neurol Sci 44, 3669–3673 (2023). https://doi.org/10.1007/s10072-023-06865-y

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