Hemolytic Uremic Syndrome, also called HUS, is a severe, life threatening condition that results in an abnormal destruction of red blood cells and can lead to kidney failure. It occurs in about 10% of those who become infected with Escherichia coli O157: H7 or any other Shiga toxin-producing E. coli, Shigella, Legionella pneumophila, and Campylobacter.
HUS Fast Facts
What is HUS?
Hemolytic uremic syndrome, or HUS, is a potentially fatal form of kidney failure. HUS was first described in medical literature as a syndrome in 1955. But it was not until 1982 that doctors learned that HUS was a secondary complication of E. coli infections.
HUS involves 2 body systems – the kidneys and the blood stream. In foodborne-based HUS, blood within the body’s capillaries begins to clot abnormally from dead red blood cells killed by Shiga toxins. Capillaries are the smallest blood vessels in your body, so when the red blood cells pass through them, they are torn apart and broken. Once this happens, waste products in the bloodstream are not able to get filtered by the kidneys, which leads to buildup of urea and other waste products in the bloodstream. This can lead to blood stream infection and kidney failure.
HUS is related to yet another condition that leads to the same clotting process within the capillaries called thrombotic thrombocytic purpura (TTP). HUS is just more widely known because of its relation to E. coli strains and other Shiga toxin-producing (STEC) E. coli strains that lead to food poisoning.
HUS is classified into two types:
What are the Causes of Hemolytic Uremic Syndrome?
HUS is generally preceded by bloody diarrhea. As the E. coli bacterium rapidly multiplies in the intestine and tightly binds to the cells in the large intestine, it emits a toxin called a Shiga toxin. This attachment makes it easier for the toxin to seep into the intestinal capillaries. It further attaches itself to the weak receptor on white blood cells, thus allowing the toxins to ride to the kidneys. The toxin then, moves into the interior of the cell, shuts down the protein machinery, and results in cellular destruction (or rather, cell death). This gives birth to coagulation and clots ultimately leading to kidney failure.
The body’s red blood cells are either destroyed by the Shiga toxin or become damaged as they try to pass through the partially obstructed microvessels.
What are the Signs and Symptoms of HUS?
Within a week after an infected person ingests Shiga-toxin producing E. coli, the bacteria will nest and severely inflame the colon – causing bloody diarrhea. These symptoms occur about a week prior to any potential onset of HUS. Other symptoms that occur, apart from bloody watery diarrhea, are vomiting and abdominal cramping. Other symptoms of HUS include:
Since the pain of HUS occurs in the right lower part of the abdomen, it is often mistaken for appendicitis. But, once colonoscopy is conducted, severe inflammation, ulceration, and pseudomembranes (made of sloughed mucosal cells, white blood cells, and fibrin) can indicate HUS disease.
The symptoms can resolve before the kidney failure and anemia associated with HUS occurs.
How is HUS Diagnosed?
Depending upon the history and medical condition related to the symptoms of HUS expressed, a health care provider will typically look for some abnormal findings through the following tests:
How is HUS Treated?
HUS is a severe condition requiring hospitalization. A person with HUS needs urgent medical attention and cannot be treated from home. Current treatments for HUS include:
What are the Long-Term Complications of HUS?
Scientific studies and medical analyses have shown the following complications related to HUS:
The early onset of medical intervention in someone with HUS is recommended to help reduce the risk of long-term complications.