Hemolytic uremic syndrome (HUS) occurs when damaged red blood cells block the kidney's filtering system, which can lead to kidney failure in children. The syndrome harms the small structures and vessels inside the kidneys. HUS causes red blood cells to clog the tiny blood vessels in the kidneys. It may cause damage to the kidney tissues. These problems make it harder for them to work and to remove waste and extra fluid from the blood.

HUS is a serious illness and can be fatal. But most children with the most common form of HUS recover with full kidney function.

In children, HUS can develop after an infection with a toxic strain of E. coli bacteria. E. coli can be found in contaminated food, such as meats and dairy foods. Outbreaks have also occurred in fast food restaurants because of undercooked hamburger meat. E. coli can also be found in contaminated water. HUS is more common during the summer and may occur in outbreaks. Outbreaks have been reported in day care centers and water parks.

HUS can also develop from taking certain medicines, such as chemotherapy medicines. It may occur at the same time as cancer. Some rare cases of HUS run in families. This means it may sometimes be caused by a gene.

A child is more at risk for HUS if they:

• Have been at a day care center or water park where E. coli has been found.
• Have eaten food from a restaurant where people have gotten sick from E. coli.
• Have family members who have had HUS.
• Are taking certain medicines.
• Are under 5 years of age.
• Have a weakened immune system.

Symptoms can be a bit different for each child. The first symptoms of HUS often last from 1 to 15 days and may include:

• Belly pain.
• Bloody or watery diarrhea.
• Vomiting.
• A fever.

Severe problems in the bowel and colon may develop in some children, even after the above symptoms are gone. In these cases, a child may have symptoms such as:

• Feeling grouchy.
• Being tired.
• Small bruises in the lining of the mouth.
• Pale skin.
• Signs of extra water loss (dehydration).

If waste and extra fluid are not removed from the body, this can cause:

• High blood pressure.
• Swollen parts of the body because of the extra fluid (edema).
• Decreased urine output.

The symptoms of HUS can seem like other health conditions. Make sure your child sees their doctor for a diagnosis.

The doctor will ask about your child's symptoms and health history. They will give your child a physical exam. Your child may also have tests, such as:

• Blood tests. These tests check blood cell counts, electrolytes, and kidney function.
• Urine tests. These tests check for blood and protein in the urine.
• Stool test. This test looks for blood and checks for bacteria such as E. coli.
• Kidney biopsy. A small piece of the kidney is removed and checked under a microscope.

There is no treatment to stop HUS. But treatment can be done to help support your child during the illness. Your child may need to be closely watched in an intensive care unit (ICU). Treatments in ICU may include:

• I.V. (intravenous) fluids and electrolytes. This is done to treat dehydration.
• Blood transfusions. Your child may need a blood transfusion to treat a medium to severe case of low red blood cell count (anemia). Children don't usually get transfusions of platelets unless they have severe bleeding.
• Nutrition. Your child may need I.V. nutrition if they have severe digestive problems.
• Dialysis. Dialysis may be needed in up to 50% of all children who develop HUS. Dialysis is a procedure to remove wastes and extra fluid from the blood when the kidneys have stopped working.
• Medicine. Your child may need medicine to treat high blood pressure or swelling

In some cases, HUS can cause death despite supportive treatment. But in most cases, children recover from HUS without any lasting damage to their health. In a few cases, the kidneys can be damaged and unable to work. The child must then continue to get dialysis. In these cases, the child may be considered for a kidney transplant.

You can help prevent E. coli infection in your family with these steps:

• Be careful when handling raw meat that may contain E. coli. Wash your hands and all surfaces. Don't cross-contaminate clean surfaces.
• Thoroughly cook all foods that may contain E. coli. Hamburger meat is a common source of E. coli.
• Use a meat thermometer when you cook. Make sure the meat reaches at least 160°F (71.1°C).
• Don't let your child drink unpasteurized juices or milk.
• Have your child wash their hands before eating and after using the bathroom.
• Don't swim in unclean swimming areas.

If your child has HUS, tell your day care center or your child's other close contacts at play groups and school. HUS is not contagious, but children can spread E. coli bacteria.

Call the doctor if your child has:

• Symptoms that don't get better or that get worse.
• New symptoms.

• Hemolytic uremic syndrome (HUS) is a rare condition that can lead to kidney failure.
• It is a serious illness and can be fatal. But most children with the most common form of HUS recover with full kidney function.
• In children, HUS can develop after an infection with E. coli bacteria. It can also develop from taking certain medicines.
• Symptoms include belly pain, diarrhea, vomiting, fever, bruising in the mouth, and swelling.
• There is no treatment to stop HUS. But treatment can be done to help support your child during the illness. Your child may need to be closely watched in an intensive care unit (ICU).

Tips to help you get the most from a visit to your child's doctor:

• Know the reason for the visit and what you want to happen.
• Before your visit, write down questions you want answered.
• At the visit, write down the name of a new diagnosis and any new medicines, treatments, or tests. Also write down any new instructions your doctor gives you for your child.
• Know why a new medicine or treatment is prescribed and how it will help your child. Also know what the side effects are.
• Ask if your child's condition can be treated in other ways.
• Know why a test or procedure is recommended and what the results could mean.
• Know what to expect if your child does not take the medicine or have the test or procedure.
• If your child has a follow-up appointment, write down the date, time, and purpose for that visit.
• Know how you can contact your child's doctor after office hours. This is important if your child becomes ill and you have questions or need advice.