62-year-old with calf swelling and platelets of 86,000
A 62-year-old woman is admitted 6 days after elective knee arthroplasty because of new painful swelling of the left calf. She has been receiving unfractionated heparin flushes through a peripherally inserted central catheter. Platelet count fell from 248,000/mm3 preoperatively to 86,000/mm3 today. Hemoglobin is unchanged, PT and aPTT are normal, creatinine is normal, and peripheral smear shows no schistocytes. Duplex ultrasonography confirms a proximal deep vein thrombosis. Which of the following is the most appropriate next step in management?
See the answer and explanation below:
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A
Explanation
Clinical Pearl:
A platelet fall of more than 50% occurring 5 to 10 days after heparin exposure, especially with new thrombosis, should be treated as heparin-induced thrombocytopenia. Management is immediate discontinuation of all heparin and prompt initiation of a non-heparin anticoagulant.
Explanation:
This patient has classic heparin-induced thrombocytopenia: the platelet count drops by more than half about a week after heparin exposure, and the new proximal DVT makes this an urgent prothrombotic syndrome rather than a bleeding disorder. Current practice is to stop every source of heparin, including flushes, and begin a non-heparin anticoagulant such as argatroban while confirmatory testing is pursued. Continuing heparin is unsafe, and platelet transfusion is generally avoided unless there is major bleeding because it can add thrombotic fuel. Warfarin should not be started alone in acute HIT because early protein C depletion can worsen thrombosis and has been linked to limb gangrene. IV immune globulin is used in selected severe immune thrombocytopenic states, not routine HIT with thrombosis. Plasma exchange is the treatment for thrombotic thrombocytopenic purpura, which would usually feature microangiopathic hemolysis, schistocytes, and often neurologic or renal involvement.
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