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[Hyperammonaemic encephalopathy due to valproic acid]
E Durán-Ferreras1, P L Jiménez-Vilches, J M Galá-Barranco
1Servicio de Neurología, Hospital Universitario de Valme, Sevilla, España. eduardoduranferreras@gmail.com
Revista De Neurologia
|May 1, 2008
Summary
Valproic acid (VPA) can cause encephalopathy, a rare side effect. This case highlights the importance of considering VPA-induced encephalopathy in confused patients, even with normal VPA levels.
Area of Science:
- Neurology
- Toxicology
Background:
- Valproic acid (VPA) is an anticonvulsant medication.
- Encephalopathy is a rare, idiosyncratic side effect of VPA treatment.
Observation:
- An 83-year-old female developed mental slowness, apathy, and confusion after starting VPA for seizures.
- Initial investigations, including VPA levels and neuroimaging, were normal, except for hyperammonaemia.
- EEG revealed diffuse encephalopathy with characteristic slow, triphasic waves.
Findings:
- Discontinuation of VPA led to rapid clinical and EEG improvement, with normalization of ammonium levels.
- The patient's symptoms resolved within 48 hours of VPA withdrawal.
- This case suggests VPA-induced encephalopathy can occur even with sub-therapeutic drug levels.
Implications:
- Clinicians should consider VPA-induced encephalopathy in patients presenting with confusion, especially after recent VPA initiation.
- Prompt recognition and VPA withdrawal are crucial for favorable outcomes.
- Further research into the mechanisms of VPA-induced encephalopathy is warranted.
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