[Hemolytic uremic syndrome (HUS): pathophysiology--with reference to the differentiation between HUS and thrombotic thrombocytopenic purpura]

Abstract

HUS and TTP have the same fundamental pathologic lesion, thrombotic microangiopathy, induced by many possible causes, all of which initially induce endothelial cell damage. This damage triggers a cascade of biochemical events that ultimately leads to the formation of thrombi in the microcirculation. HUS and TTP share hematologic and vascular abnormalities and are sometimes similar in their clinical manifestations, some authors believe they should be considered a single condition and be termed HUS/TTP. On the contrary, others consider that HUS could be defined as a disorder marked by microvascular lesions limited to the kidney, whereas TTP has generalized lesions. The causative factor(s) resulting in either HUS or TTP have not been completely elucidated, and further studies are required for precise differentiation between HUS and TTP.