Thrombotic thrombocytopenic purpura and HIV infection.

We report on a man who was HIV-seropositive and who was initially admitted following multiple episodes of syncope. He gradually developed fulminant thrombotic thrombocytopenic purpura (TTP). Twenty-one patients with TTP who were HIV-positive have been reported previously. Of these 22 patients, all treated with plasmapheresis, 7 died from TTP and 3 suffered relapse but eventually recovered. Delay in initiating plasmapheresis may be fatal. We have correlated the laboratory data of these patients at time of admission with subsequent clinical outcome; only the platelet count correlated with outcome. Patients with lower platelet counts were less likely to relapse or die with therapy. Physicians caring for patients infected with HIV should always consider the possibility of TTP in those patients with thrombocytopenia of unknown etiology. Review of the peripheral blood smear, allowing the detection of microangiopathic hemolytic anemia, is an important clue, enabling one to consider the correct diagnosis.