UC Irvine

Since the first description of thrombotic thromb-ocytopenic purpura (TTP) by Moschcowitz in 1924 (1), the diagnostic criteria of TTP has gone through inevitable evolutionary changes from triad to pentad, to dyad and inclusion of more atypical syndromes (2). This has become necessary because TTP has emerged from being an almost incurable disease to a curable disease, and several previously undefined conditions have now become recognized as atypical manifestations of this disorder (3). These include cer-tain cases of pancreatitis, hepatitis, acute respiratory distress syndrome (ARDS), peripheral digit ischemic syndrome, acute myocardial infarction, rhabdomyol-ysis and others (2–7). Early recognition of the disease and aggressive treatment with therapeutic plasma exchange are at the root of this dramatic improve-ment in outcome, and availability of this therapeutic modality now compels the clinical hematologist to be more vigilant in recognizing of this life-threatening disease (8).