Heparin induced thrombocytopenia

Heparin-induced thrombocytopenia (HIT) is a serious complication of heparin therapy that can lead to severe thrombosis. It is caused by an immune response that forms antibodies to the complex of heparin and platelet factor 4 (PF4). This can lead to a decrease in platelet count and an increased risk of thrombosis.

Causes

HIT is caused by an immune response to the complex of heparin and PF4. This immune response leads to the formation of antibodies that bind to the heparin-PF4 complex, activating platelets and leading to a prothrombotic state.

Symptoms

The symptoms of HIT can vary, but often include thrombosis, which can lead to deep vein thrombosis (DVT), pulmonary embolism (PE), or other serious complications. Other symptoms can include a decrease in platelet count, or thrombocytopenia, and skin reactions at the site of heparin injections.

Diagnosis

Diagnosis of HIT involves a combination of clinical assessment and laboratory testing. Clinical assessment includes a review of the patient's medical history, symptoms, and the timing of heparin exposure. Laboratory testing typically involves a serotonin release assay (SRA), which can detect the presence of heparin-PF4 antibodies.

Treatment

Treatment of HIT involves discontinuing heparin and starting an alternative anticoagulant. This can include direct thrombin inhibitors such as argatroban or bivalirudin, or factor Xa inhibitors such as fondaparinux. In severe cases, plasma exchange may be used to remove the heparin-PF4 antibodies from the blood.

See also

• Thrombosis
• Thrombocytopenia
• Heparin
• Platelet factor 4

References

Heparin induced thrombocytopenia Resources
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