HUS is a condition that damages the blood vessels in the kidneys. This may lead to blood clots and, in severe cases, kidney failure. Symptoms include vomiting, diarrhea, abdominal pain, and fever.

Children have the highest risk of getting HUS. However, the condition has a good recovery rate, and most people will not have severe kidney damage as a result of it.

This article explains HUS, including its symptoms, causes, treatment, and outlook.

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HUS may occur when the blood vessels inside the kidneys become damaged or inflamed. Blood clots may develop and clog the kidneys’ filtering system. This can cause kidney failure, a life threatening condition.

HUS is most common in children and is often the result of an E. coli infection. It is serious and needs appropriate treatment as soon as possible. Most people, especially children, fully recover from this condition.


Doctors classify HUS into two types: typical HUS and atypical HUS.

Typical HUS occurs in 90% of cases. The causes are the Shiga-like toxin (verotoxin) produced by E.coli and the Shiga toxin produced by Shigella dysenteriae.

Experts refer to the other 10% of cases as atypical HUS. These cases encompass several diseases with similar features. Atypical HUS has various causes, including other types of bacteria, medications, and immune processes.

The symptoms of HUS may vary depending on its cause. In most cases, the cause is an E. coli infection, which affects the digestive tract.

HUS is more common in children than in adults. However, it presents similarly in adults and children. Gastrointestinal symptoms may include:

As the infection progresses, the toxins released inside the intestines can destroy blood cells, and a person may develop anemia symptoms such as:

When HUS causes severe kidney injury, an individual may experience:

E. coli infections cause around 90% of HUS cases. E. coli is a type of bacteria that can live inside the intestines of healthy humans and animals. It is usually harmless. However, certain E. coli strains can cause diarrhea and produce the Shiga toxin.

This toxin may enter a person’s bloodstream and cause damage to their blood vessels. This can lead to the development of HUS. However, most people with an E. coli infection do not develop HUS.

Other possible causes of HUS include:

  • other infections, such as HIV, influenza, and pneumococcal bacteria
  • the use of certain medications to treat cancer or suppress the immune system after an organ transplant
  • complications from pregnancy, cancer, or autoimmune diseases

Without treatment, HUS may cause kidney failure. It can damage the small vessels inside the kidneys.

This damage may also cause inflammation and, eventually, a blood clot that can clog the filtering system of the kidney. This may lead to kidney failure, a potentially life threatening medical emergency.

In certain cases, a person with HUS may need dialysis or a kidney transplant.

The most common risk factor for HUS is an E. coli bacterial infection. Risk factors for E. coli include:

  • eating food, such as meat, that carries E. coli bacteria
  • having close contact with a person with E. coli
  • swimming in lakes or pools contaminated with feces

Other possible causes of HUS include:

  • cancer
  • reactions to certain drugs
  • organ transplantation
  • complications during pregnancy
  • very high blood pressure

The risk of developing HUS is higher for:

  • people with a weakened immune system
  • older adults
  • children aged 5 years and younger
  • people with certain genetic mutations

Healthcare professionals will perform a series of tests and a physical exam before confirming a diagnosis of HUS. The tests may include:

If the causes of HUS are unclear, healthcare professionals may conduct additional tests to help them find the condition’s origin.

Doctors may also diagnose HUS clinically if a person experiences thrombocytopenia, kidney damage, and hemolytic anemia and has had diarrhea during the last 2 weeks.

The treatment for HUS depends on the condition’s severity and causes. Treatment for HUS may involve:

In severe cases of kidney failure, a doctor may also recommend a kidney transplant.

If a person experiences bloody diarrhea or any other symptoms of HUS, they should contact a doctor as soon as possible.

People should seek emergency care immediately if they also experience symptoms such as:

  • extreme fatigue
  • unusual bleeding
  • paleness
  • swelling
  • unexplained bruises
  • decreased urine output or the absence of urination for more than 12 hours

The rate of long-term complications from HUS is low, and most people completely recover.

People who require dialysis have a high risk of long-term chronic kidney disease.

Rarely, HUS can lead to serious complications such as:

To prevent E. coli infection, a person should consider:

  • washing hands well before eating and after using the restroom
  • cooking meat to an internal temperature of at least 160°F (71°C)
  • frequently cleaning utensils and surfaces they use to prepare food
  • avoiding unpasteurized juice, cider, and milk
  • defrosting meat in a microwave or refrigerator instead of on the kitchen counter
  • keeping raw and cooked meat separate to avoid contamination
  • storing meat in the bottom part of the refrigerator to prevent its liquid from dripping onto other foods
  • avoiding swimming in water that may contain E. coli bacteria

The outlook for HUS usually depends on how soon a person starts treatment. Most people with typical HUS recover and do not develop long-term complications.

Around 85% of people can regain full kidney function without any damage.

In rare cases, HUS may damage a person’s kidneys significantly, and around 5% of people die as a result of HUS.

Long-term kidney complications occur in 5–25% of children with HUS.

HUS is a serious condition that can lead to kidney failure, and it needs immediate medical treatment. The most frequent cause of HUS is an E. coli bacterial infection. Other possible causes include cancer, pregnancy, autoimmune diseases, and genetic mutations. HUS is most common in children, but adults may experience it as well.

To prevent E. coli infections, people should always cook meat well, store raw and cooked foods separately, and wash their hands before and after touching food to avoid any possible contamination.

The outlook for HUS is generally good, with about 85% of people fully recovering from the condition without kidney damage. However, in some cases, a person may develop severe kidney damage, which may need further treatment such as dialysis or a transplant.