Related Experiment Video
Updated: Jun 1, 2026
08:47
Microdialysis of Excitatory Amino Acids During EEG Recordings in Freely Moving Rats
Published on: November 8, 2018
A case of valproate induced hyperammonemic encephalopathy
Surjit Tarafdar1, Mark Slee, Faisal Ameer
1Nephrology, Flinders Medical Centre, Bedford Park, SA 5042, Australia.
Case Reports in Medicine
|June 2, 2011
Summary
Valproate medication can cause hyperammonemic encephalopathy (VHE), a condition leading to confusion and elevated ammonia levels. Stopping valproate treatment quickly resolves symptoms and normalizes ammonia levels.
Area of Science:
- Neurology
- Clinical Pharmacology
Background:
- Sodium valproate is a widely used antiepileptic drug.
- Hyperammonemia is a potential side effect of sodium valproate treatment.
- Valproate-induced hyperammonemic encephalopathy (VHE) is a recognized but not fully understood complication.
Observation:
- A 36-year-old male on phenytoin, levetiracetam, and sodium valproate presented with acute confusion.
- Routine investigations, including therapeutic drug monitoring for phenytoin and valproate, were normal.
- Elevated serum ammonia levels were detected, prompting the discontinuation of sodium valproate.
Findings:
- The patient's confusion resolved within two days of ceasing valproate.
- Serum ammonia levels normalized concurrently with clinical improvement.
- Urea acid cycle disorders were excluded, confirming the diagnosis of VHE.
Implications:
- VHE can occur even with therapeutic valproate levels and normal liver function tests.
- Prompt recognition and cessation of valproate are crucial for managing VHE.
- Further research into the incidence and management of VHE, including potential roles for carnitine replacement, is warranted.
Related Concept Videos
01:29Hepatic Encephalopathy
DefinitionHepatic encephalopathy is a reversible neurologic syndrome that results from advanced liver dysfunction or portosystemic shunting. It leads to disturbances in cognition, behavior, and motor function due to the brain’s exposure to gut-derived toxins that the liver fails to detoxify.EtiologyThis condition develops either in the setting of acute fulminant hepatitis or progressively during chronic liver disease, such as cirrhosis and portal hypertension. Portosystemic shunting—including...
01:14Antiepileptic Drugs: Glutamate Antagonists
Glutamate is a fundamental neurotransmitter in the central nervous system, playing a vital role in neuronal communication and various cognitive processes. Glutamate stands as the principal excitatory neurotransmitter in the brain. Its presence is crucial for the communication between neurons, underpinning essential processes such as synaptic transmission, neuronal excitability, and plasticity. These functions are vital for higher-order cognitive processes, including learning and memory. The...
01:19Encephalitis l: Introduction
Encephalitis is inflammation of the brain parenchyma, most often due to infections or autoimmune processes. It presents with neuropsychiatric features such as fever, altered mental status, behavioral changes, cognitive dysfunction, seizures, focal deficits, and sometimes autonomic instability. In some cases, the meninges are also involved, resulting in meningoencephalitis.Infectious CausesInfectious encephalitis is most commonly viral but can also result from bacterial, fungal, or parasitic...
01:20Inborn Errors of Metabolism
Phenylketonuria (PKU) is a protein metabolism disorder characterized by high blood levels of the amino acid phenylalanine. This results from a mutation in the gene responsible for phenylalanine hydroxylase, an enzyme that converts phenylalanine into tyrosine. When this enzyme is deficient, phenylalanine builds up in the blood, leading to symptoms such as vomiting, rashes, seizures, growth deficiency, and severe mental retardation. An early diagnosis and a diet restricting phenylalanine intake...
01:26Encephalitis ll: Pathophysiology
Encephalitis is inflammation of the brain parenchyma caused by direct viral invasion or immune-mediated mechanisms triggered by infections or tumors. Both processes lead to neuronal injury, disrupted neurotransmission, and diverse neurological symptoms, often with overlapping clinical and pathological features.Autoimmune EncephalitisIn autoimmune encephalitis, antibodies target neuronal antigens on cell surfaces, synapses, or within neurons. A key example is anti-NMDAR encephalitis, which can...
01:18Antiepileptic Drugs: GABAergic Pathway Potentiators
γ-aminobutyric acid or GABA, plays a pivotal role as an inhibitory neurotransmitter in the brain. GABA pathway potentiators, also known as GABAergic drugs, are a class of pharmaceutical agents designed to enhance the functioning of the GABAergic system. These medications primarily treat epilepsy, a neurological disorder characterized by recurrent seizures.
The key GABA pathway potentiators used in epilepsy management are as follows.
Benzodiazepines are a well-known class of drugs used for their...
The key GABA pathway potentiators used in epilepsy management are as follows.
Benzodiazepines are a well-known class of drugs used for their...