Thrombotic thrombocytopenic purpura. I. Pathophysiology and clinical manifestations.

Thrombotic thrombocytopenic purpura is an uncommon, life-threatening disorder that affects older children and adolescents as well as adults. A variety of theories have been proposed to explain its clinical and pathologic manifestations, but the pathophysiology remains poorly understood. It is not even clear whether this disease primarily affects the endothelial cell, the platelet, or both. Most patients have no discernable predisposition to this disease. Our failure to define the pathophysiology of thrombotic thrombocytopenic purpura adequately has hampered our ability to design rational and consistently successful therapy. The present knowledge of this pathophysiology is discussed in detail. The high mortality of this disease necessitates rapid diagnosis so that therapy can be instituted as quickly as possible. The clinical manifestations and diagnostic criteria of thrombotic thrombocytopenic purpura are therefore reviewed.