Antiphospholipid syndrome in an adolescent with refractory immune thrombocytopenia and massive central venous thrombosis

Abstract

Introduction and aim. Immune thrombocytopenia (ITP) and antiphospholipid syndrome (APS) may coexist, creating a clinical paradox of simultaneous bleeding risk and thrombophilia. In children and adolescents, APS may remain unrecognised for years when thrombocytopenia dominates the early course. The thrombotic risk associated with thrombopoietin receptor agonists (TPO-RAs) in this setting remains uncertain.

Description of the case. A 17-year-old boy with refractory ITP during romiplostim therapy developed massive upper-extremity
and central venous thrombosis with near-complete superior vena cava obstruction. Persistent lupus anticoagulant, anticardi
olipin, and anti-β2-glycoprotein I antibody positivity established APS. He was treated with heparin, alteplase, and long-term
warfarin plus low-dose aspirin, while romiplostim was continued to support safe anticoagulation. No recurrent thrombosis or
major bleeding was observed during 20 months of follow-up.

Conclusion. Thrombocytopenia does not protect against thrombosis in APS. In adolescents with chronic or refractory ITP, especial
ly when vascular symptoms, unexplained prolonged aPTT, or other autoimmune red flags are present, targeted antiphospholipid
antibody testing should be considered. Management of combined ITP and APS requires individualized balancing of anticoagula
tion and platelet support, with vitamin K antagonists remaining the preferred long-term anticoagulant strategy in high-risk APS.