ABSTRACT
Background: Thrombotic thrombocytopenic purpura (TTP) is characterized by anemia, thrombocytopenia, neurological and renal involvement of variable severity and it has a dismal prognosis. Platelet-derived von Willebrand Factor-cleaving metalloprotease ADAMTS-13 activity may orient the diagnosis, but normal levels do not discard it. The most effective therapy thus known is plasmapheresis. Aim: To report the experience in 18 patients with TTP. Material and methods: Retrospective assessment of 11 patients and prospective assessment of seven subjects with TTP, aged 15 to 81 years. Results: All presented with anemia, thrombocytopenia and LDH elevation. Sixteen had neurological symptoms, five had fever, four had macroscopic urinary excretion of pigments, four had petechiae, and two had nosebleeds. Haptoglobin was low in 10 of 11 patients in whom it was measured. ADAMTS-13 had low activity in 15 of 17 patients (in 11, the inhibitor was found). Seventeen patients were treated with plasmapheresis and nine received steroids also. Seven patients died due to shock with respiratory involvement or múltiple organic failure. Conclusions: TTP has heterogeneous modes of presentation. If the diagnosis is strongly suspected, plasmapheresis can be started without laboratory confirmation. An ADAMTS-13 activity below 6 percent is almost exclusive of TTP .