Hemolytic-Uremic Syndrome

Overview :

Most cases of HUS occur after an infection in the digestive system that has been caused by toxin-producing strains of the bacterium Escherichia coli. About 75% of HUS cases in the United States are caused by the strain referred to as E. coli O157:H7, which is found in the intestinal tract of cattle, while the remaining cases are caused by non-O157 strains. Some children infected with E. coli O157:H7 will develop HUS. HUS also can follow respiratory infection episodes in young children. In the United States, there are about 20,000 infections and 250 deaths annually that are caused by E. coli O157:H7. HUS has also been known to occur in persons using drugs such as oral contraceptives, immunosuppressors, and antineoplastics, and in women during the postpartum period.

E. coli. O157:H7, first identified in 1982, and isolated with increasing frequency since then, is found in contaminated foods such as meat, dairy products, and juices. Infection with E. coli. O157:H7 causes severe gastroenteritis, which can include abdominal pain, vomiting, and bloody diarrhea. For most children, the vomiting and diarrhea stop within two to three days. However, about 5 to 10% of the children will develop HUS and will become pale, tired, and irritable. Toxins produced by the bacteria enter the blood stream, where they destroy red blood cells and platelets, which contribute to the clotting of blood. The damaged red blood cells and platelets clog tiny blood vessels in the kidneys, or form lesions to occur in the kidneys, making it difficult for the kidneys to remove wastes and extra fluid from the body, resulting in hypertension, fluid accumulation, and reduced production of urine.