Balancing Bleeding and Clot: Type 2 Heparin-Induced Thrombocytopenia With Extensive Thromboses in a Patient With Subdural Hematoma.

Heparin-induced thrombocytopenia (HIT) type 2 is a rare, immune-mediated complication of heparin therapy characterized by thrombocytopenia and paradoxical thrombosis. It results from platelet-activating antibodies against platelet factor 4 (PF4)/heparin complexes and can precipitate life-threatening thromboembolic events. Management becomes especially challenging in patients with concurrent bleeding, such as intracranial hemorrhage, where anticoagulation carries significant risk. An 87-year-old man with essential thrombocythemia and atrial fibrillation on rivaroxaban presented with a right subacute subdural hematoma after a fall. Anticoagulation was held, and he underwent burr hole evacuation with middle meningeal artery embolization, receiving prophylactic heparin postoperatively. Three weeks later, he developed a left leg deep vein thrombosis (DVT); therapeutic heparin was initiated but stopped after >50% platelet decline and hematoma progression. With a high-probability 4Ts score, an inferior vena cava (IVC) filter was placed, and he was discharged from anticoagulation pending HIT results. Six days later, he re-presented with dyspnea and limb swelling. Imaging revealed bilateral pulmonary embolism and extensive DVTs in all extremities. HIT was confirmed by positive PF4 enzyme-linked immunosorbent assay (ELISA) and serotonin release assay. He was started on argatroban and later transitioned to apixaban 5 mg twice daily once hematoma stability was confirmed. He remained neurologically stable on follow-up. This case underscores the therapeutic dilemma of managing HIT in the setting of active intracranial hemorrhage. While immediate anticoagulation is required to mitigate thrombosis, it risks worsening intracranial bleeding. Argatroban, due to its short half-life, provides a safe bridge in such scenarios. Transitioning to apixaban after radiographic stability reflects a growing trend toward individualized use of direct oral anticoagulants (DOACs) in the management of HIT. Notably, the coexistence of essential thrombocythemia and atrial fibrillation may have further amplified both thrombotic and bleeding risk, emphasizing the possible limitations of existing scoring tools such as the 4Ts in complex hematologic settings. In patients with type 2 HIT and active intracranial bleeding, anticoagulation may still be necessary to prevent fatal thromboses. Tailored multidisciplinary management can achieve favorable outcomes. This case highlights the need for further research into risk stratification frameworks that integrate concurrent hematologic disorders and competing thrombotic-hemorrhagic conditions to guide safe anticoagulant selection and timing in type 2 HIT, especially with a concurrent bleed.