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Medical Author:

Benjamin Wedro, MD, FACEP, FAAEM

Benjamin Wedro, MD, FACEP, FAAEM

Dr. Ben Wedro practices emergency medicine at Gundersen Clinic, a regional trauma center in La Crosse, Wisconsin. His background includes undergraduate and medical studies at the University of Alberta, a Family Practice internship at Queen's University in Kingston, Ontario and residency training in Emergency Medicine at the University of Oklahoma Health Sciences Center.

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Medical Editor:

Melissa Conrad Stöppler, MD

Melissa Conrad Stöppler, MD

Melissa Conrad Stöppler, MD, is a U.S. board-certified Anatomic Pathologist with subspecialty training in the fields of Experimental and Molecular Pathology. Dr. Stöppler's educational background includes a BA with Highest Distinction from the University of Virginia and an MD from the University of North Carolina. She completed residency training in Anatomic Pathology at Georgetown University followed by subspecialty fellowship training in molecular diagnostics and experimental pathology.

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In this Article

• Hemolytic uremic syndrome (HUS) facts
• What is a "syndrome?"
• What is hemolytic uremic syndrome (HUS)?
• What causes hemolytic uremic syndrome?
• What are the signs and symptoms of hemolytic uremic syndrome?
• How is hemolytic uremic syndrome diagnosed?
• What is the treatment for hemolytic uremic syndrome?
• What is the prognosis of hemolytic uremic syndrome?
• How can hemolytic uremic syndrome be prevented?
• Find a local Nephrologist in your town
• Hemolytic Uremic Syndrome Index

In E. coli-related HUS, gastroenteritis occurs with abdominal cramping, vomiting and profuse bloody, watery diarrhea. This may cause significant dehydration, weakness and lethargy, as well as electrolyte imbalances because of the loss of sodium, potassium, and chloride in the vomit and diarrhea. These symptoms may resolve before the onset of anemia and the kidney failure symptoms of HUS.

The anemia and uremia usually present with weakness, lethargy, and sleepiness. Purpura or small areas of bleeding in the skin may be seen because of low platelet counts.

The healthcare provider will have a suspicion of the disease based on the history and physical examination. Abnormal laboratory tests help confirm the diagnosis. They abnormal findings include:

• Hemolytic anemia: the red blood cell count is low and a peripheral blood smear, in which blood is examined under a microscope, will show that the red cells have been damaged and destroyed. This differentiates hemolysis (hemo=blood + lysis=destruction) from anemia caused by decreased production of blood cells in the bone marrow.
• Thrombocytopenia: a low platelet count
• Uremia: Kidney function can be measured by testing the level of waste products in the blood normally filtered by the kidney. Creatinine is a breakdown product of a muscle protein called creatine .When this level rises, it is an indication of kidney failure or uremia.
• Abnormal urine findings: Blood and protein may be found in the urine when normally they are not present.
• Stool cultures: Since E. coli O157:O7 is the most common cause of HUS, attempts are made to culture the bacteria from stool samples. The body usually clears the bacteria from the stool within a week, so a negative test does not exclude the disease. A positive test helps confirm HUS and will be reported to public health authorities to try to determine the source of the infection. In 2011, outbreaks in Europe were traced by public health authorities to tainted sprouts.

One of the distinguishing findings between HUS and TTP is a normal neurologic examination. The brain function is normal in HUS.