Hemolytic uremic syndrome (HUS) is a condition that generally occurs in children as a result of infection from a toxic strain of bacteria called Escherichia coli (E. coli) O157:H7. This infection commonly begins as diarrhea (which is often bloody). It is most likely acquired via consumption of contaminated foods or liquids or poor hand hygiene following contact with an infected person, animal, water source, or waste product. Around 5-10 percent of individuals affected by E. coli O157:H7 go on to develop HUS. Children seem to be more at risk of HUS than adults.
In HUS, the E. coli O157:H7 strain produces a poisonous substance called Shiga toxin, which can pass through the intestines into the bloodstream. The Shiga toxin then causes damage to red blood cells, platelets, and small blood vessels. The kidneys are the most targeted organ by Shiga toxin, but the brain, pancreas, liver, or heart may also be affected. As a result of this attack on the kidneys, HUS is the most common cause of sudden, short-term acute kidney failure in children.
While most children with an E. coli O157:H7 diarrheal infection never develop HUS, those who do develop very pale skin, noticeably less energy, irritability, and possibly decreased urine output. Unexplained bruising or bleeding from the nose or mouth may also occur.
A child’s pediatrician may suspect HUS after a thorough examination and review of the history of symptoms. The diagnosis is confirmed by examining a blood sample under a microscope to see if there is red blood cell destruction.
Children with HUS are usually referred to a children’s hospital for treatment, where a pediatric nephrologist (kidney specialist) and intensive care unit are available. Close monitoring of the patient’s fluid volume status, blood pressure, and kidney function are important. A child may need a blood transfusion to treat severe anemia. In about 50 percent of cases, short- or long-term dialysis (which is a blood-cleansing treatment) may be started because the kidneys are unable to filter out waste products or excess fluid from the body on their own. While more than 85 percent of patients with HUS eventually recover their normal kidney function, some with severe damage ultimately require a kidney transplant.
Most children with HUS recover completely without any permanent health damage. Still, even with a full recovery, children with HUS may have high blood pressure or other kidney-related problems in the years ahead.
Reviewed by Dr. Sara Connolly, February 2019
- Hemolytic uremic syndrome (HUS) is a complication of E. coli O157:H7 infection and is more common in children than adults.
- HUS is the most common cause of sudden, short-term acute kidney failure in children.
- Symptoms of HUS include pale skin, decreased energy, irritability, decreased urine output, and unexplained bruising or bleeding from the nose or mouth.