Hemolytic uremic syndrome caused by E. coli O157:H7

Hemolytic uremic syndrome is a life-threatening illness usually caused by infection with Shiga toxin–producing Escherichia coli O157 (STEC O157). The antecedent infection is almost always manifested as non-bloody diarrhea. In about 80% of cases, the diarrhea becomes bloody between one and five days after the onset of diarrhea. The courses of acute gastrointestinal infections, and of hemolytic uremic syndrome, in adults and children are similar.

In the United States, Escherichia coli O157:H7 causes ≈73,000 infections and 60 deaths annually. Infection progresses to hemolytic uremic syndrome in 2% to 15% of cases.

Hemolytic uremic syndrome is a disease of non-immune (Coombs negative) hemolytic anemia, low platelet count, and renal impairment. Anemia is severe and microangiopathic in nature, with fragmented red blood cells (schistocytes) in the peripheral smear, high serum lactate dehydrogenase (LDH), circulating free hemoglobin, and reticulocytes.

Hemolytic uremic syndrome develops approximately 7 days (inter-quartile range 5–8 days) after the onset of gastrointestinal symptoms and 4 (2–6) days after the onset of bloody diarrhea. Colitis as well as hemolytic uremic syndrome and CNS disease have been etiologically linked to the biological action of E. coli-derived Stx (Shigella toxin), predominantly Stx 1, 2 and 2c.
Hemolytic uremic syndrome caused by E. coli O157:H7