Pathophysiology of Thrombotic Thrombocytopenia Purpura

ABSTRACT

This review describes classic thrombotic thrombocytopenic purpura (TTP), discusses the pathogenesis of acquired and congenital TTP, describes clinical and laboratory manifestations observed in patients, and lists options for treating patients with TTP. TTP is a rare hematologic disorder characterized by thrombocytopenia and microangiopathic hemolytic anemia. It results from a congenital or acquired deficiency of a disintegrin and metalloproteinase with a thrombospondin type 1 motif, member 13 (ADAMTS-13), in plasma. Most cases are caused by an autoimmune mechanism that interferes with ADAMTS-13; however, rare inherited forms of TTP have been described (e.g., Upshaw-Schulman syndrome). It is still considered a life-threatening disease with a mortality rate of 10%–20%. Severe deficiency of ADAMTS-13 (<10%) is most often associated with congenital TTP. Although TTP is a serious hematologic emergency that is almost always fatal in untreated cases, an understanding of its pathophysiology can lead to successful treatment strategies, resulting in improved patient care and outcomes.