Hyperammonaemia and Cognitive Impairment in Epilepsy Patients Treated With Valproic Acid – Preliminary Study

Abstract

The aim: To determine whether VPA pharmacotherapy, mainly in the group of patients using subtherapeutic doses of VPA, could contribute to the occurrence of cognitive impairment. Materials and methods: The study involved 14 patients: six women and eight men, aged 24 - 77 years (mean SD ± - 52.36±13.71) diagnosed with epilepsy in accordance with the ILAE criteria (International League Against Epilepsy), in whom the main clinical complaint, in addition to poor control of epileptic seizures, were impaired concentration, attention and memory impairment. Results: Mild cognitive impairment - MCI was diagnosed in 4 patients (28.57%) (3 with elevated ammonia levels, 1 without), in 1 patient (7.14%) there was a mild level of dementia. In only one MCI case, elevated serum concentrations of valproic acid were also recorded. It is very important to highlight that cognitive impairment has never been diagnosed before (prior to VPA therapy) in this group. Of these 5 patients, in four cases, after discontinuation of the drug, an improvement in the clinical condition was achieved. In a patient with mild level dementia, the termination of therapy did not give a similar effect. This proves the possibility of other mechanisms responsible for generating these sometimes irreversible disorders. Conclusions: Regardless of the dose and concentration of ammonia in blood serum of patients diagnosed with epilepsy, VPA therapy may cause various, significant dysfunctions that significantly impair quality of life.