Two patients with heparin-induced thrombocytopenia followed by idiopathic (immune) thrombocytopenic purpura: case report.

Heparin-induced thrombocytopenia (HIT) and idiopathic thrombocytopenic purpura (ITP) are separate and well-recognized clinical syndromes, 10both having potential for disastrous outcomes. Sequential occurrence of these two diseases has not been reported in the literature. We report herein two patients who were initially diagnosed as having HIT but whose later clinical course was similar to ITP. Although dysfunction of immune system seems to play a role, the precise mechanisms for the development of these diseases are unclear. As both conditions have different natural histories and require different treatment modalities, it is important to recognize that these two diseases may be seen sequentially.