À propos d'un cas d'encéphalopathie hyperammoniémique. Rôle possible de l'acide valproïque

Three days after the treatment by valpromid (a prodrug of valproic acid) was started, a bipolar patient from the psychiatric unit presented confusion signs, space-time disorientation and loss of memories. Hyperammoniemic encephalopathy was diagnosed after performing a blood test and an electroencephalogram. To conclude, the imputability of valpromid in the apparition of the encephalopathy seems to be strongly probable since this adverse event was totally reversed at the interruption of the treatment. Risk patient profiles are not clearly identified. In this case report, the starting regime of valpromid, the association with quetiapine and the past alcoholism of the patient could be cofactors risks. Physicians should keep in mind that hyperammoniemic encephalopathy is a potential serious adverse event for patient under valpromid or valproic acid. At the present time, it remains difficult to prevent this side effect which also clearly expresses according to individual sensitivities.