Chromogenic factor X-guided warfarin monitoring in lupus anticoagulant-positive primary antiphospholipid syndrome with adrenal hemorrhage and progressive deep vein thrombosis: a case report

Antiphospholipid syndrome (APS) is a thrombotic autoimmune disorder; adrenal hemorrhage is uncommon. Treating progressive thrombosis with concurrent major bleeding is challenging, especially when lupus anticoagulant (LA) may compromise international normalized ratio (INR)-based warfarin monitoring. Case presentation: A 32-year-old Chinese man had isolated marked activated partial thromboplastin time prolongation detected preoperatively 4 years earlier. He showed persistent LA positivity and high-titer anticardiolipin and anti-β2-glycoprotein I antibodies, but no thrombosis was documented and he was lost to follow-up. One year before the current admission, he developed extensive lower-limb deep vein thrombosis (DVT) after a left ankle sprain, followed days later by right-sided lower back/flank pain. Computed tomography showed right adrenal hemorrhage with adjacent perirenal extension. Anticoagulation was withheld because of bleeding, and an inferior vena cava filter was placed. He was readmitted 2 days later with worsening pain, progressive bilateral DVT, thrombocytopenia, markedly elevated D-dimer, and persistent triple-positive antiphospholipid antibodies. After multidisciplinary review, endovascular embolization was performed for local hemostatic control. Anticoagulation was then escalated from reduced-dose enoxaparin to therapeutic-dose enoxaparin, approximately 1 mg/kg every 12 h, and warfarin was initiated. Because LA raised concern regarding INR reliability, chromogenic factor X (CFX) activity was used to guide warfarin monitoring, with a target range of 20%–40%. At 6 months, imaging showed near-complete hematoma absorption and venous recanalization, without recurrent major bleeding or new thrombosis. Conclusions: In selected LA-positive APS patients with competing risks of thrombosis and adrenal hemorrhage, endovascular hemostasis followed by cautious anticoagulation escalation and CFX-guided warfarin monitoring may be feasible when INR monitoring is potentially unreliable.