Is there a shared pathophysiology for thrombotic thrombocytopenic purpura and hemolytic-uremic syndrome?

Thrombotic microangiopathy is characterized by microvascular thrombosis coupled with thrombocytopenia, hemolytic anemia, and red blood cell fragmentation. Familiar to nephrologists and hematologists alike, classically associated with thrombotic microangiopathy are the hemolytic-uremic syndrome (HUS) and thrombotic thrombocytopenic purpura (TTP), the histories and presentations of which are closely intertwined. Not surprising, these two disorders are considered by many to be manifestations of the same disease process, whereas others consider HUS and TTP to be distinct clinical and pathologic entities. Herein are reviewed HUS and TTP along with recent progress shedding new light on possible shared pathophysiologic mechanisms for these two intriguing disorders.