Polymyositis is a rarely reported complication of COVID-19 illness, especially in children. Molecular mimicry may be a cause of hyperactivated autoimmunity, leading to various clinical manifestations, including myopathies. Symptoms vary from mild muscle weakness to severe rhabdomyolysis. We review the literature on post-COVID myositis and report a case of severe polymyositis in a 7-year-old boy, following undefined viral infection 3 weeks before the onset of muscle pain. Patient’s condition deteriorated from physical activity-associated pain in the lower limbs to severe muscle weakness leading to dysphagia and mechanical ventilation. As antibodies against SARS-CoV-2 were detected and other possible conditions causing myositis were excluded, the diagnosis of post-COVID polymyositis was considered as the most likely. The patient was treated with high doses of methylprednisolone and cyclophosphamide, resulting in improvement. Although COVID-19 is becoming a seasonal disease, the infection itself and post-viral disorders, such as polymyositis, are still of great interest and require better investigation to ensure appropriate management for each individual. Our experience suggests that aggressive immunosuppressive therapy might be a solution for severe post-COVID-related diseases. This literature review is provided in addition to the case report presented at the 29th European Paediatric Rheumatology Congress; the abstract is available online in the Proceedings of the 29th European Paediatric Rheumatology Congress.

There is insufficient dissemination of easily accessible reliable information for patients with juvenile idiopathic arthritis (JIA) in their native language on the Internet. Although there are various medical articles and scientific publications about JIA, many of them are presented in complex language, medical terminology and are intended for specialists. Aim: to design and develop an informational website for children with juvenile idiopathic arthritis and their families. The software used to realise this work: Visual Studio Code, HTML, CSS, JavaScript, Figma.com, wireframe.cc. Results and conclusion. The informative website was developed from January to May 2025 during the IT student’s bachelor thesis in close collaboration with pediatric rheumatologists and resident doctors of the Pediatric Department of Lithuanian University of Health Sciences, who took care of the quality of literacy on the website. As the result of this multidisciplinary work, a website called imunovaikai. lt was created. Congnitive value: the evidence-based but easy-to-understand informational material in native language, as provided on the website imunovaikai.lt, should create a health literacy environment that promotes understanding and engagement, which can lead to better adherence to treatment regimens and reduced emotional distress.