Hemolytic Uremic Syndrome
Hemolytic uremic syndrome (HUS) is a disease of two body systems, the blood stream and the kidney. Hemolysis describes the destruction of red blood cells. In hemolytic uremic syndrome, blood within capillaries, the smallest blood vessels in the body, begins to clot abnormally. When red blood cells pass through the clogged capillaries, they are sheared apart and broken. (hemo=blood +lysis=destruction). The second failed system, kidney failure (uremia), occurs when urea and other waste products build up in the bloodstream because the kidneys cannot filter and dispose of them. (urea=a waste chemical + emia= in the blood).

HUS is also related to another disease caused by a similar normal clotting process within the capillaries called thrombotic thrombocytic purpura (TTP). Within the medical literature, these two conditions are often considered together. HUS is more widely known, however, because it has been discussed in the press because of its relationship to a special type of E. Coli (Escherichia coli) infection associated with food poisoning.

HUS can be classified as typical or atypical. The typical type is associated with gastrointestinal (GI) signs and symptoms including vomiting and diarrhea. Atypical HUS is not associated with GI symptoms.