Hemolytic-uremic syndrome (HUS)

Alternative names:

HUS

Definition:

A disorder marked by renal failure, hemolytic anemia, thrombocytopenia (platelet deficiency), coagulation defects, and variable neurologic signs.

Causes, incidence, and risk factors:

This disorder is most common in children. It frequently occurs after a gastrointestinal (enteric) infection, often one caused by a specific E. coli bacteria (Escherichia coli O157:H7). It has also been associated with other enteric infections including Shigella and Salmonella and some non-enteric infections.

The incidence of HUS, once relatively rare, is increasing in children. It is the most common cause of acute renal failure in children. Several large outbreaks in 1992 and 1993 were attributed to undercooked hamburger contaminated with E. coli. Because of this association new labeling will appear on supermarket hamburger and temperature guidelines have been published for cooked hamburger at fast food chains and restaurants.

HUS is less common in adults. Most adult cases have been reported in patients with cancer who have received the chemotherapy drug 5-FU.

Predisposing risk factors are not known. It has been occasionally reported in association with a variety of other diseases and infections. The incidence is 1 out of 10,000 people.

HUS often begins with vomiting and diarrhea (which may be bloody). Within a week the patient develops weakness and irritability. Urine output decreases dramatically and may almost cease. Because red blood cells are being destroyed (a process called hemolysis) the patient rapidly becomes anemic and pale.