Abstract: Thrombotic thrombocytopenic purpura (TTP) is a syndrome that consists of the pentad of thrombocytopenia, microangiopathic hemolytic anemia, neurologic abnormalities, fever and renal disease. It was first described by Moschowitz in 1925 as a disease characterized by the pathological findings of hyaline thrombi in many organs. The blood protein von Willebrand factor (vWF) has a central role in promoting platelet adhesion and aggregation. The enzyme ADAMTS13 (a metalloprotease) constitutively cleaves large VWF multimers that are secreted by the endothelium into shorter strands. In many cases, it has been identified as a genetic problem due to an irregularity in several suspect genes. In other cases, the disease appears out of nowhere and this is called an idiopathic cause. In acquired TTP, an autoantibody inactivates the ADAMTS13 protease, and thus the VWF multimers remain large and abundant. The multimers bind platelets and form aggregates in the microvasculature that induce thrombus formation. The micro thrombi cause tissue ischemia, platelet consumption, and microangiopathic hemolytic anemia. Brain involvement is common and leads to stroke, seizure, confusion, and headache. Renal injury occurs in a minority of patients, and it is usually modest. The syndrome rarely present with the pentad of symptoms.. Currently, unexplained thrombocytopenia and microangiopathic hemolytic anemia are the two criteria required to establish the diagnosis. Prompt initiation of the management is an important factor in improved patient survival.
Keywords: thrombotic thrombocytopenic purpura TTP, hemolytic uremic syndrome HUS, von Willebrand factor vWF, ADAMTS13, plasma exchange