Background: The mechanism of gastroduodenitis is complex and remains to be fully elucidated. Oxygen-derived free radicals and their toxic products may play a significant role in this process. The aim of the study was to find out whether the generation of highly reactive states of oxygen is increased in chronic gastroduodenitis in children.
Material/Methods: We determined plasma and erythrocyte concentrations of malondialdehyde (MDA) in 100 children aged 6 to 17 years. In all of them gastroscopy was performed and specimens of the mucosa were obtained prior to and following treatment. The patients were divided into 2 groups, i.e., with and without improvement in the mucosal status after treatment. A control group consisted of 50 children with coeliac disease on a gluten-free diet, who did not complain of abdominal pain.
Results: Prior to treatment, the mean plasma and erythrocyte MDA concentrations were significantly higher in children with chronic gastroduodentis than in controls (p < 0.001). After treatment these variables were reduced in patients who demonstrated improvement. In patients without improvement, the mean plasma and erythrocyte MDA concentrations further increased after treatment.
Conclusions: 1. Oxygen-derived free radicals are probably involved in the pathogenesis of gastroduodentis in children. 2. Measurements of plasma and erythrocyte MDA concentrations could be used to monitor the course of disease and possibly modify treatment in gastroduodentis in children.

Keywords: gastroduodentis, Malondialdehyde, Free Radicals, children