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What is HUS?

Hemolytic Uremic Syndrome (HUS) is a disease that affects the kidneys and other organs. It poses a substantial threat to children as one of the leading causes of sudden acute kidney failure. HUS is most common in the warmer months of the year and follows a gastrointestinal illness caused primarily by a particular strain of bacteria known as Escherichia coli O157:H7. This gastrotintestinal illness has been nicknamed AHamburger Disease@. While other types of E. coli are common in the gastrotintestinal tract of healthy humans, this particular strain (O157:H7) is not usually present. These E. coli O157:H7 bacteria produce extremely potent toxins which are the main cause of the symptoms related to the gastrointestinal illness.

Some individuals may develop fever with this infection. People of all ages can get E. coli O157:H7 gastroenteritis, however, young children and the elderly tend to develop severe symptoms. This infection is highly contagious. Thousands of people become infected each year with many epidemics reported in Canada, the United States, Japan, and Europe.

E. coli O157:H7 bacteria infect the intestine of cattle and less frequently the intestines of other animals. Typically carried in the feces, it can contaminate the meat during and after slaughtering. These bacteria are associated mainly with consumption of undercooked ground beef, unpasteurized milk and cheese, and contaminated water sources. Once someone has eaten contaminated food, this infection can pass from person-to-person by hand-to-mouth contact. Poor hand-washing and improper food handling are factors which lead to the spread of these bacteria.

Who develops HUS?

Approximately 1 in every 10 children who have E. coli O157:H7 gastroenteritis (Hamburger Disease), will go on to develop HUS. HUS is caused by the effect of toxins (produced by the E. coli bacteria) on the body's circulation affecting the red blood cells, the kidneys, and, in some cases, the brain. According to a study conducted by the Canadian Pediatric Kidney Disease Research Centre (CPKDRC) between 1986 and 1988, diagnosis of HUS usually occurs between the 8^th and 12th day of the diarrheal illness. However, many children have developed HUS earlier. A very small number of children will develop the disease beyond 2 weeks of their diarrheal illness. Although HUS does sometimes occur in the adult population, it is more common among children, most often affecting those less than 5 years of age. At this time we are not sure why some children with E. coli O157:H7 gastroenteritis develop HUS while others escape kidney damage.

What are the symptoms and implications of HUS?

Children with HUS usually experience irritability and fatigue, paleness of the skin, and often a decrease in the amount of urine output. Following an E. coli O157:H7 gastrointestinal illness, one must check for signs of HUS. If HUS develops, children spend an average of 2 weeks in hospital mainly to care for kidney problems of varying severity. Depending on the severity of the illness, a large majority will require some form of blood transfusion and approximately 50% will need temporary kidney dialysis. Modern medical care has allowed approximately 97% of affected children to survive this illness, however, long-term follow-up is very important.