Suspected Heparin-Induced Thrombocytopenia with Subsequent Major Bleeding Following Anticoagulation for Deep Vein Thrombosis: A Case Report.

Heparin-induced thrombocytopenia (HIT) is a potentially fatal drug reaction, caused by the formation of IgG antibodies, usually following treatment with heparin. We report the case of a 77-year-old hypertensive man with a history of deep vein thrombosis of the right lower limb who was treated with anticoagulation therapy with heparin and acenocoumarol. Four days later, his platelet count had reduced from 154 × 10³/µL to 55 × 10³/µL, a 64% reduction. The patient had several complications which included acute kidney injury, atrial fibrillation, and a right frontal acute cerebral infarct. The patient had a left inferior vena cava filter placed, and subsequently underwent catheter directed thrombolysis and thrombectomy. One week later, he had recurrent epistaxis and bleeding from the gums. He was severely anemic (Hb 6.8 g/dL) and had deranged coagulation. The patient had advanced kidney failure, was anemic and was 77 years old, which increased his risk of bleeding. The 4 Ts score indicated a high clinical suspicion of HIT, however, heparin/PF4 antibody testing and functional assays were not performed, and therefore, a definitive diagnosis of HIT was not made. The patient was managed with fresh frozen plasma, packed red blood cells, and tranexamic acid. The patient improved clinically. This case illustrates the need for prompt assessment of declining platelet counts in the presence of heparin therapy and consideration of HIT.