Hemolytic uremic syndrome in children.

The majority of postdiarrheal hemolytic uremic syndrome is caused by Escherichia coli O157:H7. The organisms are carried in the intestines of cattle; partially cooked contaminated hamburger is the single most common vector. The E. coli produce a potent cytotoxin that gains access to the circulation, is taken up by glycolipid receptors on glomerular endothelial cells, is internalized, and causes cell death. Associated phenomena include the activation of platelets, leukocytes, and the coagulation cascade, as well as the production of cytokines. Although some patients experience a mild or incomplete syndrome, life-threatening multisystem involvement can occur. Treatment is supportive, but plasma exchange may be useful in selected high-risk subsets. Efforts to prevent colitis from evolving into hemolytic uremic syndrome include the oral administration of material to bind the toxin in the gut. Mortality remains at 5% to 10%; about 4% are left with end-stage renal failure, and approximately 50% suffer mild chronic kidney damage.