Valproate-induced encephalopathy with predominant pancerebellar syndrome

Abstract

Valproate-induced hyperammonemic encephalopathy is a rare event clinically characterized by impaired sensorium, vomiting, headache, seizures and focal neurological deficits. The pathogenesis of this dreadful complication is not well understood, although hyperammonemia has been implicated in causation of encephalopathy. In this submission, we have highlighted a case of valproate-induced encephalopathy who presented mainly with bilateral cerebellar features and generalized slowing on electroencephalogram. High index of suspicion of valproate-induced hyperammonemic encephalopathy is required if diffuse ataxia is present as it is a potentially reversible clinical disorder.

Cerebellar Dysfunction and Ataxia in Patients with Epilepsy: Coincidence, Consequence, or Cause?

“…In valproate treatment, tremor is more often observed as an adverse event, and ataxia could be a sign of hyperammonemic encephalopathy. 65 Another reversible form of neurotoxicity was also reported with valproate, mimicking multiple system atrophy with parkinsonism and cerebellar symptoms. 66 There is very limited information on the exact mechanism by which most antiepileptic drugs induce ataxia.…”

Cerebellar Dysfunction and Ataxia in Patients with Epilepsy: Coincidence, Consequence, or Cause?

“…In valproate treatment, tremor is more often observed as an adverse event, and ataxia could be a sign of hyperammonemic encephalopathy. 65 Another reversible form of neurotoxicity was also reported with valproate, mimicking multiple system atrophy with parkinsonism and cerebellar symptoms. 66 …”

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“…Valproic acid rarely causes ataxia as a direct adverse effect.However, its effects on the metabolism of other medications and the risk of encephalopathy from hyperammonemia have be known to produce ataxia [9,20]. Valproic acid can produce encephalopathy either byaffecting hepatic function or precipitation of hyperammonemia.…”