Hemolytic uremic syndrome

HUS is a rare condition that can lead to kidney failure in children. Kidney failure develops as a result of destruction of the small, functional structures and vessels inside the kidney. HUS is a serious illness and potentially fatal.

What causes hemolytic uremic syndrome?

HUS is more common during the summer months and may occur in outbreaks. Outbreaks have been reported in daycare centers, water parks, and fast food restaurants as a result of inadequately cooked hamburger meat. HUS is most common in younger children between 6 months and 4 years, but can occur at any age.

HUS has several known causes and some unknown causes. Typically in children, HUS develops after an infection with the E. coli bacterium. E. coli may be found in contaminated food such as dairy products and meat. HUS can also develop as a result of taking certain medications, or may result from a cancer present in the body, although these causes are less common. In less than 5 percent of HUS cases, the disorder is inherited by a dominant gene (a gene passed from parent to child with a 50/50 risk) or recessive gene (each parent carries one copy of the gene and the child inherits both copies; the chance is 25 percent with each pregnancy).

What are the symptoms of hemolytic uremic syndrome?

The following are the most common symptoms of HUS. However, each child may experience symptoms differently.

The initial symptoms of HUS frequently last from one to 15 days and may include symptoms in the digestive tract such as the following:

• Abdominal pain
• Bloody or watery diarrhea
• Vomiting

Severe problems in the bowel and colon may develop in some cases. In these cases, even if the digestive symptoms are no longer present, a child may still exhibit the following symptoms:

• Irritability
• Fatigue
• Small, unexplained bruises visible in the lining of the mouth
• Pale skin
• Dehydration

The child may produce little urine because damaged red blood cells and other factors may clog the tiny blood vessels in the kidneys, or cause lesions in the kidneys, making them work harder to remove wastes and extra fluid.

The body's inability to rid itself of excess fluid and waste may, in turn, cause the following symptoms:

• High blood pressure
• Swelling of the hands and feet
• Generalized fluid accumulation in the tissues (edema)

The symptoms of hemolytic uremic syndrome may resemble other medical conditions or problems. Always consult your child's physician for a diagnosis.

How is hemolytic uremic syndrome diagnosed?

In addition to a complete medical history and physical examination, diagnostic procedures for HUS may include:

• Blood tests (to assess blood cell counts, electrolytes, and kidney function)
• Urine tests (to check for blood and protein)
• Stool tests (to assess for blood)
• Abdominal x-ray - a diagnostic test which uses invisible electromagnetic energy beams to produce images of internal tissues, bones, and organs onto film.

Treatment for hemolytic uremic syndrome:

Specific treatment for HUS will be determined by your child's physician based on:

• Your child's age, overall health, and medical history
• The extent of the condition
• Your child's tolerance for specific medications, procedures, or therapies
• Expectations for the course of the condition
• Your opinion or preference

There is no known treatment that can stop the progression of the syndrome once it has started. Initially, treatment may be supportive, which means that there is no cure for the specific disease, so it is necessary to treat the symptoms. If your child shows signs of dehydration and electrolyte irregularities, these conditions will be treated first. Other therapies may include:

• Intensive care - Close observation and monitoring in an intensive care unit (ICU) may be necessary
• Blood transfusions - Blood transfusions may be necessary to treat moderate to severe cases of anemia (low red blood cell count)
• Nutrition - Your child may require intravenous (IV) nutrition if he/she is having severe digestive tract complications
• Dialysis - Dialysis may be required in up to half of all children who develop HUS. Dialysis is a medical procedure to remove wastes and additional fluid from the blood after the kidneys have stopped functioning
• Medication - Medications may be required to treat your child's blood pressure, which may be elevated

Preventing hemolytic uremic syndrome:

Completely cooking all foods that may contain hamburger meat can prevent HUS that is caused by E. coli. Other possible sources of E. coli include unpasteurized juices or milk.

If your child has HUS, it is important to notify your daycare center or your child's other close contacts (i.e., play groups, school). HUS is not contagious, but spread of the E. coli bacterium is contagious. About 10 to 20 percent of children with an E. coli infection are likely to develop HUS.