Hemolytic uremic syndrome (HUS) is primarily a disease of infancy and early childhood and is classically characterized by the triad of microangiopathic hemolytic anemia, thrombocytopenia, and acute renal failure. In 1955, Gasser et al first described hemolytic uremic syndrome as a self-limited illness associated with a prodrome of diarrhea that resulted in spontaneous recovery.[1] Though the description of this childhood illness has not changed significantly through the years, additional insight into the pathology and disease process have come to light recently.
E coli serotype O157:H7 has been associated with more than 80% of infections leading to hemolytic uremic syndrome. The shiga-like toxin affects endothelial cells and initiates intravascular thrombogenesis. After entering the circulation via the gastrointestinal mucosa, the toxin preferentially localizes to the kidneys, inhibiting protein synthesis and eventually leading to cell necrosis or apoptosis. Endothelial cell damage subsequently potentiates renal microvascular thrombosis by promoting activation of the blood coagulation cascade. Platelet aggregation results in a consumptive thrombocytopenia. Microangiopathic hemolytic anemia results from mechanical damage to red blood cells circulating through partially occluded microcirculation.