Heparin-induced thrombocytopenia

Heparin-induced thrombocytopenia (HIT) type II is caused by an immune response involving antibody formation to the heparin-platelet factor 4 complex. An activation of platelets leads to an uncontrolled generation of thrombin which in turn leads to arterial and/or venous thrombosis. Untreated this condition can result in loss of limbs or fulminant pulmonary embolism. As the main trigger is the administration of unfractionated heparin it is paramount to immediately stop heparinization while concomitantly initiating alternative anticoagulation. This can include rapidly effective factor Xa inhibitors or direct thrombin inhibitors.