What is HUS?
What is Hemolytic uremic syndrome?

Hemolytic uremic syndrome (HUS) is a kidney condition that happens when red blood cells are destroyed and block the kidneys’ filtering system. If your kidneys stop working, you have acute kidney injury—the sudden and temporary loss of kidney function.

Red blood cells contain hemoglobin—an iron-rich protein that gives blood its red color and carries oxygen from the lungs to all parts of the body.
When the kidneys and glomeruli—the tiny units within the kidneys where blood is filtered—become clogged with the damaged red blood cells, they are unable to do their jobs.

The most common cause of HUS is infection with a strain of E. coli bacterium called O157:H7, although other bacteria and viruses may also cause this condition. Adolescents and adults of all ages are susceptible to HUS, though it is most common in children younger than age 5. About one in 10 children who are infected with E. coli O157:H7 develop HUS.

E. coli O157:H7

What causes HUS?

The most common cause of hemolytic uremic syndrome in children is an E. coli (Escherichia coli) O157:H7 infection of the digestive system.

The digestive system is made up of the gastrointestinal, or GI, tract—a series of hollow organs joined in a long, twisting tube from the mouth to the anus—and other organs that help the body break down and absorb food.

Normally, harmless strains of E. coli are found in the intestines and are an important part of digestion. However, if a child becomes infected with the O157:H7 strain of E. coli, the bacteria will lodge in the digestive tract and produce toxins that can enter the bloodstream.

The toxins travel through the bloodstream and can destroy the red blood cells.

E.coli O157:H7 can be found in

  • undercooked meat, most often ground beef
  • unpasteurized, or raw, milk
  • unwashed, contaminated raw fruits and vegetables
  • contaminated juice
  • contaminated swimming pools or lakes

Less common causes, sometimes called atypical hemolytic uremic syndrome, can include

  • taking certain medications, such as chemotherapy
  • having other viral or bacterial infections
  • inheriting a certain type of hemolytic uremic syndrome that runs in families

what are the Symptoms of HUS?

A child with hemolytic uremic syndrome may develop signs and symptoms similar to those seen with gastroenteritis—an inflammation of the lining of the stomach, small intestine, and large intestine— such as

  • vomiting
  • bloody diarrhea
  • abdominal pain
  • fever and chills
  • headache

As the infection progresses, the toxins released in the intestine begin to destroy red blood cells. When the red blood cells are destroyed, the child may experience the signs and symptoms of anemia—a condition in which red blood cells are fewer or smaller than normal, which prevents the body’s cells from getting enough oxygen.

Signs and symptoms of anemia may include

  • fatigue, or feeling tired
  • weakness
  • fainting
  • paleness

As the damaged red blood cells clog the glomeruli, the kidneys may become damaged and make less urine. When damaged, the kidneys work harder to remove wastes and extra fluid from the blood, sometimes leading to acute kidney injury.

Other signs and symptoms of hemolytic uremic syndrome may include bruising and seizures.

When hemolytic uremic syndrome causes acute kidney injury, a child may have the following signs and symptoms:

  • edema—swelling, most often in the legs, feet, or ankles and less often in the hands or face
  • albuminuria—when a child’s urine has high levels of albumin, the main protein in the blood
  • decreased urine output
  • hypoalbuminemia—when a child’s blood has low levels of albumin
  • blood in the urine

Which children are
more likely to develop HUS?

Children who are more likely to develop hemolytic uremic syndrome include those who
  • are younger than age 5 and have been diagnosed with an E. coli O157:H7 infection
  • have a weakened immune system
  • have a family history of inherited hemolytic uremic syndrome

Hemolytic uremic syndrome occurs in about two out of every 100,000 children.
seek immediate care for any children experiencing urgent symptoms,
such as
unusual bleeding, swelling, extreme fatigue, decreased urine output, unexplained bruises

How is HUS diagnosed?

A healthcare provider diagnoses hemolytic uremic syndrome with

  • a medical and family history
  • a physical exam
  • urine tests
  • a blood test
  • a stool test
  • kidney biopsy

What problems
can happen with HUS?

Some children who develop hemolytic uremic syndrome have mild problems and recover without permanent damage to their health. However, HUS may have serious and sometimes life-threatening complications, including

  • acute kidney injury, requiring kidney dialysis
  • high blood pressure
  • blood-clotting problems that can lead to bleeding
  • nervous systems issues causing irritability, restlessness, and sometimes seizures
  • heart problems
  • chronic, or long lasting, kidney disease
  • stroke
  • coma

What are the
treatment options for HUS?

A health care provider will treat a child with hemolytic uremic syndrome by addressing

  • urgent symptoms and preventing complications
  • acute kidney injury
  • chronic kidney disease

In most cases, health care providers do not treat children with hemolytic uremic syndrome with antibiotics unless they have infections in other areas of the body.

With proper management, most children recover without long-term health problems.

Treating Urgent Symptoms and Preventing Complications

A health care provider will treat a child’s urgent symptoms and try to prevent complications by

  • observing the child closely in the hospital
  • replacing minerals, such as potassium and salt, and fluids through an intravenous (IV) tube
  • giving the child red blood cells and platelets— cells in the blood that help with clotting—through an IV
  • giving the child IV nutrition
  • treating high blood pressure with medications
Treating Acute Kidney Injury

If necessary, a health care provider will treat acute kidney injury with dialysis—the process of filtering wastes and extra fluid from the body with an artificial kidney. Most children with acute kidney injury need dialysis for a short time only.

Treating Chronic Kidney Disease (CKD)

Some children may sustain significant kidney damage that slowly develops into CKD. Children who develop CKD must receive treatment to replace the work the kidneys do. The two types of treatment are dialysis and transplantation.

serious is HUS?

HUS can be a very serious disorder. With prompt treatment, chances for recovery are good.

Most people enter this intimidating world of critical care without any medical background. They have no preparation for the circumstances they find themselves in with a critically ill child or family member.

Don’t underestimate your own abilities, your unique relationship with the patient, or your role in becoming an essential member of the team working towards the best outcome for the patient.

To be a constructive team member, you may need to learn how the other members of the team interact, what their roles are, how their decision making and information sharing proceeds. You will learn about protocols, and what their expectations of you are.

You can be certain that everyone shares the best of intentions. Their first priority is to the patient. So on the most basic level you are intensely united with the medical team in the mutual mission to save your loved one.

Numerous studies support that when family members actively engage and communicate, there are better patient outcomes and a lower risk of medical errors. Don’t be afraid to be assertive if you feel something is wrong, or that maybe the doctors or nurses have missed some detail that you sense is important. Different doctors and nurses rotate on and off shift. You do not. You are your child’s or loved ones greatest advocate.

About Dialysis

When the patient is not peeing as much as usual, that could be a sign that the kidneys are not working as well as they should. The medical team will make decisions based, in part, on these lab results:

  • Blood Urea Nitrogen (BUN)
  • Potassium (K)
  • Creatinine (Cr)

A brief
medical glossary

For hus patients and their families

From Anemia & Creatinine

to Hypertension & Nephrology

to Sequelae and Urea

check it out
more from the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)

What about repeat infections?

Practice food safety. Prepare food using proven methods for cleaning, thawing, heating and refrigeration. Make sure everyone in your family knows how to wash their hands with soap and warm water after using the toilet, petting animals, playing or working outside and before touching food to prevent risk of infection.

Repeat infections with E. coli are rare, but can happen.

What are the longterm consequences of HUS?

HUS survivors usually escape immediate serious complications. However, some are left with long-term damage to organs other than the kidneys, especially to the pancreas (diabetes) or brain (nervous system impairment). Some require chronic dialysis and a kidney transplant within a few years, because of severe kidney damage.

A larger number of HUS survivors go on to develop future health disorders related to acute kidney injury, including hypertension, proteinuria, and low glomerular filtration rate (GFR).

Here’s a broader scope of long term outcomes resulting from hemolytic uremic syndrome.

Will we need follow up care?

If you’ve had HUS, it’s important to see a nephrologist every year for the first 10 years after recovery, and every other year after that. They will check for signs of high blood pressure and kidney problems.

from our navigational map

“It was 2:00 in the afternoon. I distinctly remember the time because my husband was at work, and my 6-year-old was in school and I said to myself, “I’ll just pop over to the ER real quick and be back home before anyone notices.

… A long month later when I finally left the hospital …”

HUS stories