In hemolytic uremic syndrome there is

Refer Robbins page no 942Typical (epidemic, classic, diarrhea-positive) hemo- lytic uremic syndrome. This is the best-characterized form of HUS. Most cases occur following intestinal infection with strains of E. coli (the most common being O157:H7) that produce Shiga-like toxins, so-called because they resemble those made by Shigella dysenteriae (Chapter 17). Epidemics have been traced to various sources, most commonly the ingestion of contaminated ground meat (as in hamburgers), but also drinking water, raw milk, and person-to-person transmission. However, most cases of typical HUS caused by E. coli are sporadic. Less com- monly, infections by other agents, including Shigella dysen- teriae, can give rise to a similar clinical picture. Typical HUS can occur at any age, but children and older adults are at highest risk. Following a prodrome of influenza-like or diarrheal symptoms, there is a sudden onset of bleeding manifestations (especially hematemesis and melena), severe oliguria, and hematuria, associated with microangiopathic hemolytic anemia, thrombocytope- nia, and (in some patients) prominent neurologic changes