Heparin-Induced Thrombocytopenia
Heparin-induced thrombocytopenia (HIT) is an immune-mediated complication of heparin adminictyation that occurs in approximately 0.5-5% of patients receiving heparin. HIT is a prothrombotic disorder that presents with a 50% decrease in platelet count and/or thrombotic event manifesting usually 5-10 days after starting heparin but may occur earlier with prior adminictyation. When clinical manifestations of HIT occur, heparin should be discontinued, and alternative therapies for anticoagulation should be considered, while laboratory evaluation for HIT is initiated. In the intensive care unit (ICU), the diagnosis of HIT can be confused by all the potential causes of thrombocytopenia in critically ill patients. HIT is also associated with a risk for adverse outcomes due to its hypercoagulable nature and is an important cause of thrombophilia in the ICU setting.