RT Book, Section A1 Sharma, Aditya M. A1 Bartholomew, John R. A2 Dean, Steven M. A2 Satiani, Bhagwan A2 Abraham, William T. SR Print(0) ID 1105291707 T1 HEPARIN-, LOW–MOLECULAR WEIGHT HEPARIN–, AND WARFARIN-INDUCED SKIN NECROSIS T2 Color Atlas and Synopsis of Vascular Diseases YR 2015 FD 2015 PB McGraw-Hill Medical PP New York, NY SN 9780071749541 LK accesscardiology.mhmedical.com/content.aspx?aid=1105291707 RD 2024/11/12 AB A 53-year-old woman was treated with intravenous unfractionated heparin (UFH) for an acute pulmonary embolism. She was started on 10 mg of warfarin on her fourth day of heparin therapy. Her baseline platelet count was normal, but decreased to 86 × 109/L by day 7 of treatment. Her international normalized ratio (INR) was 3.2 at that time and heparin was discontinued. A platelet factor 4 (PF 4)–heparin immunoassay was found to be positive, consistent with a diagnosis of heparin-induced thrombocytopenia (HIT). Three days later she developed a violaceous discoloration of both breasts that progressed to full-thickness skin necrosis and warfarin-induced skin necrosis was diagnosed (Figure 62-1). Warfarin was discontinued and the direct thrombin inhibitor (lepirudin) instituted as the platelet count dropped further to 22 × 109/L. She ultimately required extensive surgical debridement of both the breasts and reconstructive surgery. Warfarin was later resumed cautiously at 1 mg/d after full platelet recovery (overlapped with lepirudin) until the INR was therapeutic (>2) for two consecutive days.