Chronic valproate encephalopathy – an important differential diagnosis of cognitive decline within the scope of a valproate therapy. Case report and literature review

Aims: Chronic valproate encephalopathy is a rare adverse effect of continuous valproate therapy, which can go along with psychomotor retardation, (pseudo-) dementia and decreased higher-level cognitive functions and which, most of the time, manifests itself with a significant latency (at least 6 months) after the start of the treatment. Thus it is often misinterpreted as a symptom of a degenerative process within the scope of a vague primary disease.

Methods: Case report and literature review

Results: We report on a 8 1/2 years old patient diagnosed with focal idiopathic epilepsy. 4 years after the beginning of valproate therapy (following an attempt of reduction with subsequent dose reconstruction due to visible EEG-decline) distinct problems in school achievements became visible, which, in the psychometrical testing, went along with a significant aggravation

(K-ABC: SIF 99 ->81). Moreover, a subtle frontal volume reduction in the MRT of the brain became visible in contrast to previous images. After differential diagnosis discussion (dementia degeneration within the scope of focal idiopathic epilepsy vs. chronic valproate encephalopathy vs. vague primary disease with dementia process) we initiated a step-by-step withdrawal of valproate. Despite return EEG-aggravation, the patient displayed a significant improvement in the neuropsychological results of examination, including reconstitution of the initial value with documented stability up to 3 years after finishing the medication. The MRI of the brain after 12 months showed a decline of the frontal volume reduction.

Conclusion: Even within the scope of a long-term therapy with valproate without significant adverse effects when starting the therapy, differential diagnosis of a chronic valproate encephalopathy has to be considered in case of a (pseudo-) dementia symptomatology, and an attempt of drug withdrawal, within strict neuropsychological diagnostic processes and repeated brain MRI-scans, has to be considered.

chronic valproate encephalopathy - side effects - pseudo dementia - valproate