Damage to the small blood vessels in the kidneys can cause clots that clog the organ’s filtering system. This can lead to life-threatening kidney failure.
Hemolytic uremic syndrome (HUS) is a condition that can occur when the small blood vessels in your kidneys become damaged and inflamed. This damage can cause clots to form in the vessels. The clots clog the filtering system in the kidneys and lead to kidney failure, which could be life-threatening.
Anyone can develop HUS, but it is most common in young children. In many cases, HUS is caused by infection with certain strains of Escherichia coli (E. coli) bacteria. The first symptom of this form of HUS is several days of diarrhea, which is often but not always bloody.
HUS may also be caused by other infections, certain medications or conditions such as pregnancy, cancer or autoimmune disease. In some cases, HUS is the result of certain genetic mutations. These forms of HUS usually do not cause diarrhea. .
HUS is a serious condition. But timely and appropriate treatment usually leads to a full recovery for most people, especially young children.
The signs and symptoms of HUS may vary, depending on the cause. Most cases of HUS are caused by infection with certain strains of E. coli bacteria, which first affect the digestive tract. The initial signs and symptoms of this form of HUS may include:
All forms of HUS — no matter the cause — damage the blood vessels. This damage causes red blood cells to break down (anemia), blood clots to form in the blood vessels and kidney damage. Signs and symptoms of these changes include:
See your doctor immediately if you or your child experiences bloody diarrhea or several days of diarrhea followed by:
Seek emergency care if you or your child doesn't urinate for 12 hours or more.
The most common cause of HUS — particularly in children under the age of 5 — is infection with certain strains of E. coli bacteria. E. coli refers to a group of bacteria normally found in the intestines of healthy humans and animals. Most of the hundreds of types of E. coli are normal and harmless. But some strains of E. coli cause diarrhea.
Some of the E.coli strains that cause diarrhea also produce a toxin called Shiga toxin. These strains are called Shiga toxin-producing E. coli, or STEC. When you are infected with a strain of STEC, the Shiga toxin can enter your bloodstream and cause damage to your blood vessels, which may lead to HUS. But most people who are infected with E. coli, even the more dangerous strains, don't develop HUS.
Other causes of HUS can include:
An uncommon type of HUS — known as atypical HUS — can be passed down genetically to children. People who have inherited the mutated gene that causes this form of HUS won't necessarily develop the condition. But the mutated gene might be activated after exposure to a trigger, such as an infection, the use of certain medications or a chronic health condition.
The majority of HUS cases are caused by infection with certain strains of E. coli bacteria. Exposure to E. coli can occur when you:
The risk of developing HUS is highest for:
HUS can cause life-threatening complications, including:
Meat or produce contaminated with E. coli won't necessarily look, feel or smell bad. To protect against E. coli infection and other foodborne illnesses:
To confirm a diagnosis of HUS, your doctor is likely to perform a physical exam and recommend lab tests, including:
If the cause of HUS is not clear, your doctor may also recommend additional tests to help determine the cause.
HUS requires treatment in the hospital. Lost fluids and electrolytes must be carefully replaced because the kidneys aren't removing fluids and waste as efficiently as normal.
In the hospital, you may need intravenous (IV) transfusions of red blood cells or platelets.
If you have lasting kidney damage from HUS, your doctor might recommend a medication to lower your blood pressure, to prevent or delay further kidney damage.
If you develop complications or have the form of HUS that's caused by a genetic mutation (atypical HUS), your doctor may recommend eculizumab (Soliris) to help prevent additional damage to your blood vessels.
Before taking eculizumab, you will need to receive or have already received a vaccination to prevent meningitis, a potential and serious side effect of the medicine.
Depending on your symptoms, the cause of your HUS and whether you have any complications, your doctor may recommend other treatments, including:
If you or your child is experiencing symptoms of HUS after several days of diarrhea, call your doctor immediately and be prepared to answer these questions:
If you or your child has an illness that causes vomiting or diarrhea, it's a good idea to try to replace the fluids that have been lost with an oral rehydrating solution, such as CeraLyte, Pedialyte or Oralyte.