Hemolytic uremic syndrome (HUS)

Overview

Hemolytic uremic syndrome (HUS) is a condition that can occur when small blood vessels become damaged and inflamed. This damage can cause clots to form in the vessels all through the body. The clots can damage the kidneys and other organs. Hemolytic uremic syndrome can lead to kidney failure, which can be life-threatening.

Anyone can get hemolytic uremic syndrome. But it's most common in young children. Most often, infection with certain strains of Escherichia coli (E. coli) bacteria is the cause.

Other infections, certain medicines or conditions such as pregnancy, cancer or autoimmune diseases can cause hemolytic uremic syndrome. It also can be the result of certain gene changes.

Hemolytic uremic syndrome is serious. But treating it in time leads to a full recovery for most people, especially young children.

Symptoms

The symptoms of hemolytic uremic syndrome vary, depending on the cause. The first symptoms of hemolytic uremic syndrome caused by E. coli bacteria might include:

• Diarrhea, which is often bloody.
• Pain, cramping or bloating in the stomach area.
• Fever.
• Vomiting.

All forms of hemolytic uremic syndrome damage blood vessels. This damage causes red blood cells to break down, called anemia. The condition also causes blood clots to form in the blood vessels and, in turn, damage the kidneys.

Symptoms of these changes include:

• Loss of color in the skin.
• Extreme tiredness.
• Easy bruising.
• Unusual bleeding, such as bleeding from the nose and mouth.
• Decreased urinating or blood in the urine.
• Swelling, called edema, of the legs, feet or ankles. Swelling occurs less often in the face, hands, feet or entire body.
• Confusion, seizures or stroke.
• High blood pressure.

When to see a doctor

See a member of your health care team right away if you or your child has bloody diarrhea or several days of diarrhea followed by:

• Urinating less.
• Swelling.
• Bruising.
• Unusual bleeding.
• Extreme tiredness.

Seek emergency care if you or your child doesn't urinate for 12 hours or more.

Causes

The most common cause of hemolytic uremic syndrome is infection with certain strains of E. coli bacteria. This is especially true for children under age 5. Some of the E. coli strains make a toxin called Shiga toxin. These strains are called Shiga toxin-producing E. coli (STEC).

Most of the hundreds of types of E. coli are typical and harmless. But some strains of E. coli can lead to hemolytic uremic syndrome.

Other causes of hemolytic uremic syndrome can include:

• Other infections. This can include infection with pneumococcal bacteria, human immunodeficiency virus (HIV) or a flu virus.
• Certain medicines. These can include some of the medicines used to treat cancer and some medicines used to keep people who receive donor organs from rejecting the organs.
• Complications of other conditions. Rarely, these conditions can include pregnancy or conditions such as autoimmune disease or cancer.

An uncommon type of hemolytic uremic syndrome, called atypical, can be passed down through families. People who inherit the gene that causes this form of hemolytic uremic syndrome don't always get the condition. But an infection, the use of certain medicines or ongoing health conditions can start hemolytic uremic syndrome in people with the gene.

Risk factors

Hemolytic uremic syndrome caused by E.coli can occur if you:

• Eat meat, fruit or vegetables with the bacteria.
• Swim in pools or lakes that have feces with the bacteria.
• Have close contact with an infected person.

The risk of getting hemolytic uremic syndrome is highest for:

• Children 5 or younger.
• People who have weakened immune systems.
• People with certain gene changes.

Complications

Hemolytic uremic syndrome can cause life-threatening complications, including:

• Kidney failure, which can be sudden, called acute, or happen over time, called chronic.
• High blood pressure.
• Stroke or seizures.
• Coma.
• Clotting problems, which can lead to bleeding.
• Heart problems.
• Digestive tract problems, such as problems with the intestines, gallbladder or pancreas.

Prevention

Meat or produce that has E. coli won't always look, feel or smell bad. To protect against E. coli infection and other illnesses from foods:

• Don't drink milk, juice or cider that isn't processed to make it safe to drink, called pasteurized.
• Wash hands well before eating and after using the restroom and changing diapers.
• Clean utensils and food surfaces often.
• Cook meat to an inside temperature of at least 160 degrees Fahrenheit (71 degrees Celsius).
• Defrost meat in the microwave or refrigerator, not on the counter.
• Keep raw foods separate from other foods. Don't put cooked meat on plates that had raw meat on them.
• Store meat below produce in the refrigerator to cut the risk of liquids such as blood dripping on produce.
• Avoid unclean swimming areas. Don't swim if you have diarrhea.

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