Hemolytic Uremic Syndrome

Hemolytic uremic syndrome (HUS) is a serious condition that can damage your child's kidneys and cause them to stop working properly. HUS most often develops after an infection with certain strains of E. coli bacteria. It can cause anemia, low platelet levels and kidney injury and requires prompt medical care. Most children with HUS recover with supportive treatment, although some may develop long-term kidney problems.

What Causes Hemolytic Uremic Syndrome?

HUS most commonly develops after an infection with a strain of E. coli that produces Shiga toxin. These bacteria can cause severe diarrhea, which may be bloody. The Shiga toxin can enter the bloodstream from the intestine and damage the small blood vessels that supply the kidneys and other organs. This damage can cause red blood cells to break apart and platelets to be used up, while also interfering with the kidneys' ability to filter waste and extra fluid from the blood.

HUS can have other causes as well. These include:

• Certain other infections
• Some medications, including certain chemotherapy drugs
• Rare genetic changes

Symptoms of HUS

HUS often begins with symptoms of an intestinal infection, particularly diarrhea caused by Shiga toxin-producing E. coli. Your child may have:

• Abdominal pain or cramping
• Diarrhea, which may be bloody
• Vomiting
• Fever

As HUS develops, symptoms may occur because of anemia, low platelets and kidney injury. These can include:

• Extreme tiredness or weakness
• Pale skin
• Easy bruising or small red or purple spots on the skin
• Decreased urination
• Swelling, particularly in the face, hands, feet or ankles
• Dehydration
• High blood pressure
• Changes in alertness or behavior in more severe cases

If your child develops significantly decreased urination, unusual sleepiness, swelling or other concerning symptoms after a diarrheal illness, seek medical care promptly.

Diagnosing HUS

Your child's medical history and physical exam are important parts of diagnosing HUS, particularly if symptoms develop after a diarrheal illness. Blood and urine tests can help determine whether your child has HUS and how severely the kidneys are affected. Testing may include:

• Blood tests to check red blood cells, platelets, kidney function and electrolyte levels
• Urinalysis to look for blood, protein and other signs of kidney injury
• Stool testing to identify Shiga toxin or the bacteria that produce it
• Additional testing when needed to determine whether HUS has another cause

How Is Hemolytic Uremic Syndrome Treated?

There is no single treatment that cures HUS caused by Shiga toxin-producing E. coli. Instead, treatment focuses on protecting your child's kidneys, maintaining the right balance of fluids and electrolytes, and treating complications while the body recovers. Some children can be cared for with close monitoring, while children with severe HUS may need intensive care.

Treatment may include:

• Carefully managed fluids and electrolytes
• Blood transfusions when needed to treat severe anemia
• Medications to control high blood pressure
• Nutritional support
• Close monitoring of kidney function and urine output
• Dialysis if the kidneys cannot remove enough waste or fluid

Most children with HUS caused by E. coli recover without needing long-term dialysis. In rare cases, HUS can cause permanent, severe kidney damage. Children who develop irreversible kidney failure may eventually need a kidney transplant.