This woman has a combination of hemolytic anemia with fragmented RBCs on peripheral smear; thrombocytopenia; fever; neurologic symptoms; and renal dysfunction -- a classic pentad of symptoms that characterizes thrombotic thrombocytopenic purpura (TTP). Approximately 90% of patients will respond to plasmapheresis. Patient should be emergently treated with largevolume plasmapheresis. Sixty to 80 mL/kg of plasma should be removed and replaced with fresh-frozen plasma. Treatment should be continued daily until the patient is in complete remission. Platelet transfusions in patients with TTP are contraindicated and can be associated with acute clinical deterioration. Antiplatelet agents, splenectomy, intravenous immunoglobulin, and immunosuppressive agents have not been of reliable benefit to patients with.