Heparin is a common anticoagulant, often used after orthopedic, cardiac and abdominal surgery. Heparin prevents life-threatening clots from developing in the deep veins of the legs and arms after surgery. During the period of immobilization after surgery, blood can pool in the deep veins, allowing clots to form. These clots can break away, causing lethal embolisms to the brain and lungs. Heparin is used to prevent clots but can also induce thrombocytopenia.
Drop in Platelet Count
Thrombocytopenia is the medical term for a low platelet count. Platelets are the blood cells that form clots in the body in order to prevent hemorrhage. Heparin can induce an immune response against the platelets. Patients with antibodies against heparin drop their platelet counts. Heparin-induced thrombocytopenia is considered a drop in the platelet count by 50 percent from baseline. In patients receiving heparin for the first time, evidence of heparin-induced thrombocytopenia or HIT may be delayed 5 to 10 days. In patients with prior exposure to heparin, a low platelet count can occur in a matter of hours. The drop in platelet count can be moderate to severe according to the "Thrombosis Journal." Platelets will start to rise usually two or three days after discontinuing the medication.
Thrombosis
Counterintuitively, HIT can cause thrombosis, which according to the "Thrombosis Journal" is one of the signs of HIT. The journal goes on to say that thrombosis that occurs with HIT is associated with 20 to 30 percent mortality. Thrombosis can occur in the arterial system, venous system or both. According to the American Heart Association journal, "Circulation," signs of a deep vein thrombosis in the legs include pain, tenderness, sudden swelling and discoloration. Where the thrombosis occurs depends on the patient's clinical picture. Patients with cardiovascular disease will often develop thrombosis in the arterial system. Orthopedic patients typically develop thrombosis in their lower extremity veins.
Severe Bruising or Skin Discoloration
Heparin-induced thrombocytopenia can produce bruising or discoloration of the fingers or toes. The extremities are very susceptible to small clots that break away from the larger clots in the legs. Discoloration or blackening or gangrenous appearance of the fingers or toes can be an indication of severe HIT. Severe bruising or blackening around the injection site of the heparin should be brought to a health care provider's attention immediately. The first treatment will be to stop the heparin, but sometimes in severe cases of thrombosis another type of anticoagulant will be necessary to prevent further clot formation.
