Background: The aim of the study was to assess diurnal melatonin secretion in children with refractory epilepsy (N=74) as compared to children without epileptic seizures (N=37) and to compare melatonin secretion in children with focal and generalized refractory epilepsy.
Material/Methods: In the study group 4 subgroups were defined: children with focal symptomatic epilepsy, focal cryptogenic epilepsy, generalized symptomatic epilepsy, and generalized cryptogenic epilepsy. Melatonin level was measured every 3 hours using the RIA method.
Results: Analysis of diurnal melatonin secretion indicated a lower level of the hormone in patients with refractory epilepsy. The daily rhythm of melatonin secretion in the study group was maintained, with a peak shift of melatonin secretion especially visible in the subgroup with generalized symptomatic refractory epilepsy in the age group between 6 months and 3 years of age.
Conclusions: The hypothesis may be formed that a lowered level of melatonin in the study group in relation to the comparison group is the consequence of the natural course of epilepsy or is influenced by antiepileptic drugs.

Keywords: Epilepsy, Generalized - physiopathology, Epilepsy - physiopathology, Circadian Rhythm - physiology, Child, Preschool, Child, Case-Control Studies, Adolescent, Melatonin - secretion, Pilot Projects, Sleep - physiology