Thrombotic thrombocytopenic purpura and its look-alikes: A single institution experience

At presentation, variant or "look-alike" conditions can resemble TTP. We reviewed charts of 26 consecutive patients treated for presumed TTP. Of 15 classic TTP patients, 11 were tested for ADAMTS13; all showed severe deficiency, and inhibitor levels correlated with probability of relapse. The variant TMA group consisted of 8 patients who had active clinical disorders which overlapped with TTP. Variant TMA patients had higher creatinine and worse prognosis than classic TTP patients. "Look-alike" disorders included ITP with intravascular hemolysis following administration of WinRho™, and human granulocytic anaplasmosis. These conditions had not been previously described as TTP look-alikes.