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What is hemolytic uremic syndrome (HUS)?
Hemolytic uremic syndrome (HUS) is a condition involving red blood cells and your kidneys. HUS happens after you get an infection in your digestive system. The infection makes toxins that destroy red blood cells. These damaged cells block the kidneys’ filtering system and can cause your kidneys to fail.
For you to be diagnosed with HUS, the infection must cause 3 disorders:
- hemolytic anemia (not enough red blood cells)
- thrombocytopenia (not enough platelets)
- renal (kidney) failure.
Most cases of HUS happen after someone has become infected with E. coli bacteria. E. coli is a common bacteria that people normally have in their digestive tract. But certain strains produce the toxins that destroy the red blood cells and damage your kidneys.
Anyone can get HUS, but it is more common in children and older adults. Many people who get an E. coli infection do not develop HUS.
Symptoms of HUS
The first symptoms of HUS are vomiting and diarrhea. The diarrhea might have blood in it. Around 5 to 10 days after the diarrhea starts, you or your child might start developing signs of anemia. Anemia happens when you don’t have enough red blood cells to carry oxygen to your cells. Symptoms include:
- bloody diarrhea
- weakness and lethargy
Later, more symptoms may appear, such as:
- pale skin
- unexplained bruising or bleeding
- swelling of the face, hands, feet or any other part of the body
- decreased urination
- no urination
- seizures (these are rare).
Call your doctor right away if you or your child have bloody diarrhea plus decreased urine output, unexplained bruises, unusual bleeding, or extreme fatigue.
What causes HUS?
Most cases of HUS occur after an E. coli infection. You can catch an E. coli infection by:
- Eating undercooked ground beef (for example, if the inside of a hamburger that you have eaten was very pink).
- Drinking contaminated (impure) water.
- Drinking unpasteurized (raw) milk.
- Eating unwashed, contaminated raw vegetable and fruits.
- Working with cattle.
Healthy beef and dairy cattle may carry E. coli in their intestines. When the animals are slaughtered and the meat is ground, the E. coli bacteria can mix into the meat. Cooking the meat usually kills the bacteria.
The most common way to get infected with E. coli is to eat undercooked ground beef. You can be infected with E. coli if you don’t use a high enough temperature to cook your beef, or if you don’t cook it long enough. When you eat undercooked beef, the bacteria go into your stomach and intestines.
Ponds and lakes can become contaminated with E. coli. If you come into contact with this water, you can get E. coli. Sometimes water that has the bacteria is accidentally used to irrigate crops. This can contaminate fruits and vegetables.
The bacteria can also pass from person to person in day care centers and nursing homes. If you have this infection, you should wash your hands well with soap after going to the bathroom. If you don’t, you can give the bacteria to other people when you touch things, especially food.
Other less common causes of HUS include the use of certain medicines, certain infections, and pregnancy.
How is HUS diagnosed?
Your doctor will perform a physical exam. He or she will order lab work, including blood and urine tests. These tests will show signs of anemia and kidney failure. More advanced tests include a stool culture or a kidney biopsy.
Can HUS be prevented or avoided?
If you or your child are infected with E. coli, there’s nothing you can do to prevent it from developing into HUS. The key is to avoid the E. coli infection. To lower your risk of being infected with E. coli, follow these rules:
- Wash your hands carefully with soap before you start cooking.
- Cook ground beef until you see no pink anywhere.
- Don’t taste small bites of raw ground beef while you’re cooking.
- Don’t put cooked hamburgers on a plate that had raw ground beef on it.
- Cook all hamburgers to at least 155°F. A meat thermometer can help you test your hamburgers.
- In restaurants, always order hamburgers and steaks that are cooked well done so that no pink shows.
- Defrost meats in the refrigerator or the microwave. Don’t put meat on the counter at room temperature to defrost.
- Keep raw meat and poultry separate from other foods. Use hot water and soap to wash cutting boards and dishes after raw meat and poultry have touched them.
- Wash all fruits and vegetables thoroughly with clean water before eating them.
- Drink only clean water.
- Don’t drink raw milk.
- Refrigerate leftovers right away or throw them away.
- People with diarrhea should wash their hands with hot water and soap often, for at least 30 seconds.
- People who work in day care centers and homes for the elderly should wash their hands often, too.
- Do not swim in dirty lakes or rivers. Don’t swim if you have diarrhea.
- Wash your hands well after petting farm animals.
Those at highest risk of developing HUS are children under 5 and adults over 75.
Most people who become infected with E. coli won’t get HUS. If you or your child do, you will need to go to the hospital. Your doctor will want to watch your kidney function and make sure you keep enough fluids in your body.
Some of the treatment you or your child might need include:
- Red blood cell transfusions to reverse symptoms.
- Platelet transfusions to help the blood clot more normally.
- Dialysis to help failing kidneys. During dialysis, a machine is used to filter waste products from the blood. Dialysis is only needed in the most severe cases of HUS. It is usually temporary. People with severe kidney damage could need it long-term.
Living with HUS
Most people who are diagnosed with HUS go on to make a full recovery. But it is a serious illness. If you or your child have significant damage to your kidneys, you may need regular transfusions or dialysis. Left untreated, HUS can cause death. Children with HUS tend to have better outcomes than adults.
Questions to ask your doctor
- How did I get E. coli infection?
- Are there any medicines I can take?
- Will I need dialysis?
- Should I have my family tested for coli infection?
- Will there be any permanent damage to my kidneys?
- What changes should I make to my diet?
- I work at a day care center. Should I let the parents know that I have coli infection?
- Should I stop eating ground beef?
- How often should I wash my hands?
Copyright © American Academy of Family Physicians
This information provides a general overview and may not apply to everyone. Talk to your family doctor to find out if this information applies to you and to get more information on this subject.