Heparin-induced thrombocytopenia and thrombosis.

Heparin-induced thrombocytopenia (HIT) and heparin induced thrombocytopenia with thrombosis (HITT) ar rare complications associated with use of unfractionate heparin (UFH) or low-molecular-weight heparin (LMWH) HIT is a benign clinical condition characterized by a mil drop in platelet count with no clinical significance. HIT is an immune-mediated reaction associated with a wide spread "hypercoagulable" state resulting in arterial an venous thrombosis. There is a higher incidence of HIT with UFH use than with LMWH use. Orthopedic surger patients are at higher risk for developing HITT than are patients who receive prophylactic heparin for cardiovascular surgery or medical reasons. Therapy for patients suspected of having HITT should begin with immedi ate discontinuation of heparin in any form followed by pharmacologic inhibition with thrombin (e.g., recombinant hirudin [lepirudin], argatroban, danaparoid sodium).