Complications of an E. coli O157:H7 infection include, but are not limited to, the following:
- Hemolytic uremic syndrome (HUS) (develops in 5-15% of cases, and has a mortality rate between 3-7%)
- Thrombotic thrombocytopenic purpura (TTP)
- Severe colitis (inflammation of the colon)
- Chronic kidney failure
- Hematuria (blood in urine)
- Proteinuria (protein in urine)
- Intestinal strictures (narrowing of intestine)
- Intestinal perforations (penetration of intestine, fluid can flow out)
Most complications are a result of Shiga toxins that are produced by the E. coli bacteria.
Although HUS and TTP are separate conditions, they can develop simultaneously in a patient with an E. coli O157:H7 infection. With TTP-HUS, fibrin-coated platelets create blood clots (thombi) in the microvascular system. Red blood cells are shredded by the fibrin. The result is a severe reduction of red blood cells and platelets.