Heparin-induced thrombocytopenia as a cause of prolonged low platelet count in a patient with thrombotic thrombocytopenic purpura treated with plasmapheresis.

Thrombotic thrombocytopenic purpura (TTP) is a rare disorder belonging to thrombotic microangiopathies (TMA) and is caused by functional deficiency of the ADAMTS-13 metalloproteinase. Plasma exchange (PE) remains the treatment of choice in this disease. Here, were describe the case of a patient who apparently recovered from TTP following multiple sessions of PE, but remained thrombocytopenic. Careful analysis revealed the development of heparin-induced thrombocytopenia (HIT) that precluded platelet count (PLT) normalization. Full normalization of PLT followed discontinuation of PE and low-molecular weight heparin.