Hemolytic uremic syndrome: an emerging health risk.

Hemolytic uremic syndrome is caused primarily by Shiga toxin-producing Escherichia coli O157:H7. The most common cause of acute renal failure in children, hemolytic uremic syndrome also can occur in adults. Characteristic features of the syndrome are microangiopathic anemia, thrombotic thrombocytopenia, and renal failure. Although the presentation of this syndrome is diverse, the classic prodromal illness is bloody diarrhea following ingestion of hamburger meat contaminated with E. coli O157:H7, the most common mode of infection in the United States. Children with hemolytic uremic syndrome generally present with gastroenteritis complaints (e.g., abdominal pain or tenderness, nausea or vomiting, fever, anemia); affected adults may be asymptomatic. Complications from hemolytic uremic syndrome can include intussusception, chronic renal failure, and seizures in severe cases. Because an incubation period of approximately one week occurs between the start of diarrhea and the onset of hemolytic uremic syndrome, physicians should maintain a high index of suspicion; early laboratory testing is important to diagnose and manage this syndrome. Obtaining a complete blood count and stool culture and performing Shiga toxin testing are the first of a series of tests that may help diagnose hemolytic uremic syndrome.