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Post-mastectomy seroma — USMLE Step 3 MCQ

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HardSurgeryPost-mastectomy seromaUSMLE Step 3

A postoperative patient receiving unfractionated heparin has a platelet fall from 248,000 to 92,000/mm³ on day 7 and a new proximal leg thrombosis. There is no major bleeding and no strong alternative cause. What should be done while HIT testing is sent?

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Correct answer: C — Stop all heparin and begin therapeutic-intensity argatroban while testing proceeds

The best answer is “Stop all heparin and begin therapeutic-intensity argatroban while testing proceeds”. The timing, greater-than-50% platelet fall and new thrombosis give a high-probability 4Ts score. Heparin must be stopped immediately and a non-heparin anticoagulant started at therapeutic intensity. Warfarin is delayed until platelet recovery because early use can precipitate venous limb gangrene.

Reference: ASH Guideline: Heparin-Induced Thrombocytopenia: https://www.hematology.org/education/clinicians/guidelines-and-quality-care/clinical-practice-guidelines/venous-thromboembolism-guidelines/heparin-induced-thrombocytopenia