Chronic Sodium Valproate Intake to Treat Epilepsy Inducing Hyperammonaemia Encephalopathy

Sodium valproate, frequently prescribed as an antiepileptic, can cause encephalopathy secondary to hyperammonia, even after chronic use. We report the case of a 75-year-old patient with Parkinson's disease and epilepsy presenting a coma without deficit, with a normal cerebral morphological work-up, an electroencephalogram ruling out status epilepticus, a cerebrospinal fluid culture ruling out neuromeningeal infection, and a normal metabolic work-up apart from hyperammonia explained by sodium valproate intake.