About E. coli

From the nation’s leading law firm representing victims of E. coli and other foodborne illness outbreaks.

Chapter 7

Complications of E. coli infection

A Life-Threatening Complication of E. coli Infection—Hemolytic Uremic Syndrome

E. coli O157:H7 and other Shiga toxin-producing E. coli (STEC) infections can lead to a severe, life-threatening complication called the hemolytic uremic syndrome (HUS). [4, 13]

HUS accounts for the majority of the acute deaths and chronic injuries caused by the bacteria. [3] HUS occurs in 2-7% of victims, primarily children, with onset five to ten days after diarrhea begins. [23, 44] “E. coli serotype O157:H7 infection has been recognized as the most common cause of HUS in the United States, with 6% of patients developing HUS within 2 to 14 days of onset of diarrhea.” [44, 45] And it is the most common cause of renal failure in children. [26, 45, 48]

Approximately half of the children who suffer HUS require dialysis, and at least 5% of those who survive have long term renal impairment. [44] The same number suffers severe brain damage. [46] While somewhat rare, serious injury to the pancreas, resulting in death or the development of diabetes, also occurs. [47] There is no cure or effective treatment for HUS. [47] And, tragically, children with HUS too often die, with a mortality rate of five to ten percent. [26]

Once Shiga toxins attach to receptors on the inside surface of blood vessel cells (endothelial cells), a chemical cascade begins that results in the formation of tiny thrombi (blood clots) within these vessels. [33, 45] Some organs seem more susceptible, perhaps due to the presence of increased numbers of receptors, and include the kidney, pancreas, and brain. [26, 33] Consequently, organ injury is primarily a function of receptor location and density. [33, 54]

Once they move into the interior of the cell (cytoplasm), Shiga toxins shut down protein machinery, causing cellular injury or death. [33, 46] This cellular injury activates blood platelets too, and the resulting “coagulation cascade” causes the formation of clots in the very small vessels of the kidney, leading to acute kidney failure.

The red blood cells are either directly destroyed by Shiga toxin (hemolytic destruction), or are damaged as cells attempt to pass through partially obstructed micro-vessels. [33, 46] Blood platelets become trapped in the tiny blood clots, or they are damaged and destroyed by the spleen. [46]

By definition, when fully expressed, HUS presents with the triad of hemolytic anemia (destruction of red blood cells), thrombocytopenia (low platelet count), and renal failure (loss of kidney function). [33, 45] Although recognized in the medical community since at least the mid-1950s, HUS first captured the public’s widespread attention in 1993 following a large E. coli outbreak in Washington State that was linked to the consumption of contaminated hamburgers served at a fast-food chain. [6, 28] Over 500 cases of E. coli were reported; 151 were hospitalized (31%), 45 persons (mostly children) developed HUS (9%), and three died. [6, 28]

Of those who survive HUS, at least five percent will suffer end stage renal disease (ESRD) with the resultant need for dialysis or transplantation. [47] But, “because renal failure can progress slowly over decades, the eventual incidence of ESRD cannot yet be determined.” [33] Other long-term problems include the risk for hypertension, proteinuria (abnormal amounts of protein in the urine that can portend a decline in renal function), and reduced kidney filtration rate. [33, 47] Since the longest available follow-up studies of HUS victims are 25 years, an accurate lifetime prognosis is not really available and remains controversial. [47]

You can read more about HUS at About-HUS.com.

Other Complications from E. coli Infection

IBS is a chronic disorder characterized by alternating bouts of constipation and diarrhea, both of which are generally accompanied by abdominal cramping and pain. [50] Suffering an E. coli O157:H7 infection has been linked to the development of post-infectious irritable bowel syndrome (IBS). This link was demonstrated by the Walkerton Health Study (WHS), which followed one of the largest O157:H7 outbreaks in the history of North America. [49] In this outbreak, contaminated drinking water caused over 2,300 people to be infected, resulting in 27 recognized cases of HUS, and 7 deaths. The WHS followed 2,069 eligible study participants. Among its findings, WHS noted that, “Between 5% and 30% of patients who suffer an acute episode of infectious gastroenteritis develop chronic gastrointestinal symptoms despite clearance of the inciting pathogens.” [49]

Not surprisingly, E. coli O157:H7 infection is associated with long-term emotional disruption as well, not just for the victim, but for entire families. [51] A recent study reported that “parents experienced long-term emotional distress and substantive disruption to family and daily life” following an E. coli O157:H7 infection in the family. [51]

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