Endothelial function in children with idiopathic uveitis and uveitis associated with juvenile idiopathic arthritis

Background. Uveitis – inflammation of the choroid of the eye – is one of the severe comorbid conditions in rheumatic diseases, mainly juvenile idiopathic arthritis, often asymptomatic, untimely diagnosed, and progressive with the risk of vision loss. Purpose – to determine the state of endothelial function in children with idiopathic uveitis and uveitis associated with juvenile arthritis using an occlusion test, taking into account the characteristics and activity of uveitis. Materials and Methods. Between 2023 and 2025, 69 children were examined and divided into three groups: 12 children with idiopathic uveitis, 26 patients with juvenile idiopathic arthritis without uveitis, and 26 patients with JIA-associated uveitis. All patients underwent brachial artery ultrasonography and endothelial function assessment using occlusion test parameters. Results. According to the results of the study, it was found that flow-mediated dilation (FMD) of the brachial artery serves as a practical diagnostic approach in the assessment of vascular endothelial function in children with idiopathic uveitis and uveitis associated with juvenile arthritis. In children with autoimmune uveitis, endothelial dysfunction was observed to a greater extent, manifested by a reduction in mean vessel diameter, an increase in the pulsatility index, and a decrease in the resistance index. These alterations were accompanied by a significant reduction in diastolic blood flow velocity and the development of hypoxic disturbances, which may potentially aggravate the course of the inflammatory process in the eye and contribute to a «vicious circle» of disease progression. Hypoergic and normoergic types of reaction were identified in 60.52% of cases. The presence of these disturbances confirms the feasibility of using the occlusion test as a method for monitoring the course of autoimmune uveitis in children. It also highlights the necessity of further investigation of endothelial function alterations in autoimmune diseases, taking into account the activity of the inflammatory process and their impact on the quality of life of affected children. Conclusions. The application of the occlusion test as a screening tool for evaluating the course of autoimmune uveitis and uveitis associated with juvenile arthritis in children has considerable practical value for the assessment of endothelial function alterations in autoimmune diseases, particularly in relation to the activity of the inflammatory process and their influence on the quality of life of affected patients. The identification of significant abnormalities substantiates the potential of the occlusion test as a reliable method for monitoring the course of autoimmune uveitis in children, emphasizing its diagnostic and prognostic utility.