The AACT toxicology question of the day for today: . . Two types of heparin-induced thrombocytopenia have been identified. What are these and how are they characterized? . . . . Scroll down for the answer. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . There are two types of heparin-induced thrombocytopenia (HIT): Type I and Type II. According to the cited reference, “Type I is the most common form of thrombocytopenia and is self-limiting. Mild thrombocytopenia occurs in the first two days after heparin initiation and normalizes even with continued heparin therapy. The mechanism of the thrombocytopenia is not autoimmune and is due to a direct effect of heparin on platelet activation.” The author describes type II HIT as “[a] more serious form [and] an immune mediated disorder characterized by the formation of antibodies against heparin-PF4 complex. This disorder has also been called heparin-associated immune thrombocytopenia (ITP), heparin-associated thrombocytopenia and thrombosis (HITT), and the white clot syndrome. (Lovecchio F. Heparin-induced thrombocytopenia 2014 Clin Tox 52(6): 579-583
Posted on: Wed, 12 Nov 2014 15:18:32 +0000