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Heparin-induced thrombocytopenia — ABIM Board MCQ

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HardHematology/OncologyHeparin-induced thrombocytopeniaABIM Board

A 63-year-old develops a platelet fall from 240,000 to 82,000/microL seven days after unfractionated heparin began for DVT and now has a new pulmonary embolism. His 4Ts score is high and bleeding risk is acceptable. What should be done immediately?

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Correct answer: B — Stop heparin and begin therapeutic non-heparin anticoagulation

The best answer is “Stop heparin and begin therapeutic non-heparin anticoagulation”. A high-probability clinical picture with new thrombosis requires immediate discontinuation of all heparin and therapeutic-intensity non-heparin anticoagulation while immunologic testing proceeds. Waiting for confirmation exposes the patient to additional thrombosis. Low-molecular-weight heparin can cross-react, platelet transfusion does not treat the prothrombotic process, and thrombocytopenia in HIT signals platelet activation rather than protection from clotting.

Reference: ASH Heparin-Induced Thrombocytopenia Guideline Pocket Guide: https://www.hematology.org/-/media/hematology/files/education/clinicians/guidelines-quality/documents/watermarked-pocket-guides/watermark-ash_vte_hit_pocketguide.pdf