Modern Pediatrics. Ukraine. (2026).4(156): 126-131. doi: 10.15574/SP.2026.4(156).126131
Soltys R. I.¹, Nazar R. Ya.², Dubei L. Ya.¹, Soltys I. M.² , Kotsai B. R.^1,5, Dorosh O. I.^1,4, Lisnyi A. Ye.¹, Kamut N. V.¹, Dubey N. V.¹, Shevtsiv U. S.^3
1Danylo Halytsky Lviv National Medical University, Ukraine
²Lviv Regional Oncology Clinical Diagnostic Center, Ukraine
³Lviv State University of Physical Culture named after Ivan Boberskyi, Ukraine
⁴NPE LRC “Clinical Center of Pediatrics”, SP “Specialized Center”, Lviv, Ukraine
⁵CNPE “1st Territorial Medical Association of Lviv”, VP “St. Nicholas Hospital”, Ukraine

For citation: Soltys RI, Nazar RYa, Dubei LYa, Soltys IM, Kotsai BR, Dorosh OI et al. (2026). Venous thrombosis in adolescents and young adults: epidemiology and pathogenetic mechanisms. Modern Pediatrics. Ukraine. 4(156): 126-131. doi: 10.15574/SP.2026.4(156).126131.
Article received: Jan 24, 2026. Accepted for publication: May 12, 2026.

Venous thromboembolism (VTE) has traditionally been considered a disease of older age; however, over the past decades, a steady increase in its incidence among adolescents and young adults has been observed. In this population, thrombosis develops in the setting of relatively preserved endothelial integrity and is driven by distinct biological determinants compared with older patients, indicating the need to reconsider conventional risk paradigms.
Aim – to summarize contemporary global evidence regarding the epidemiology, pathogenesis, and risk factors  of  VTE  in  individuals  aged  12-50  years  within  the  framework  of   the thromboinflammation
concept and to outline perspectives for personalized prevention.
The study substantiates a conceptual model of early-onset VTE as an immuno-coagulative continuum integrating genetic predisposition and inflammatory activation. An expanded risk stratification approach incorporating biomarkers of thromboinflammation and fibrinolytic dysfunction is proposed. An analytical review of international registries, meta-analyses, and position statements of major professional societies addressing age-specific features of VTE was conducted. VTE in young individuals follows a multi-hit model integrating inherited thrombophilia (factor V Leiden, prothrombin G20210A mutation, antithrombin deficiency, protein C and S deficiencies), hormonal exposure, cancer- and catheter-related triggers, metabolic disturbances, and immune activation. The thromboinflammation paradigm explains pathogenesis through the interaction of endothelial dysfunction, hypercoagulability, neutrophil extracellular traps (NETs), cytokine imbalance (IL-6), and hypofibrinolysis (plasminogen activator inhibitor-1, PAI-1). Impairment of the fibrinolytic system appears to be an underrecognized contributor to recurrent VTE in young patients.
Conclusions. Adolescents and young adults represent a distinct clinico-pathobiological subgroup. Future preventive strategies should integrate targeted modulation of inflammatory mechanisms alongside anticoagulant therapy.
The authors declare that there is no conflict of interest.
Keywords: venous thromboembolism, adolescents, young adults, thrombophilia, thromboinflammation, neutrophil extracellular traps, interleukin-6, plasminogen activator inhibitor-1, fibrinolysis, personalized prevention.

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