Introduction and objective: The aim of the study was to analyse the clinical symptoms and laboratory abnormalities of seizure disorders in febrile children infected with pathogens from the Herpesviridae family – human herpesvirus 6 (HHV-6), human cytomegalovirus (HCMV), and Epstein–Barr virus (EBV). Materials and methods: A total of 75 children were included in the study, including 64 patients after a febrile seizure and 11 patients after an epileptic seizure triggered by infection. The control group consisted of 36 children with developmental delay. Routine inflammatory markers were analysed including C-reactive protein (CRP), procalcitonin (PCT), erythrocyte sedimentation rate (ESR), and white blood count (WBC). Pathogens were detected using standard diagnostic methods. Results: Compared to control group, median CRP and PCT were significantly higher in children with all types of febrile seizures, and ESR was significantly higher in children with simple and complex seizures. Most children with WBC below and above the normal range were children with simple febrile seizures plus and those with complex seizures, respectively. HHV-6 was detected in 33% of children. HCMV was found in 5%, and EBV in 4% of children. There was no significant correlation between children with and without primary HHV-6 infection regarding age, gender, febrile seizures type and first-time seizures, nor significant differences in inflammatory markers except for WBC. The difference between the number of children with three-day fever and those without rash was borderline significant (p = 0.06); children with primary HHV-6 infection without rash had more frequent first-time seizures (p = 0.04). Conclusions: The clinical course of seizure disorders and the intensity of the inflammatory reaction in children were mild. HHV-6 was the most common causative agent of fever and seizure disorders.

infection, inflammatory response, primary HHV-6 infection, febrile seizures, generalised epilepsy