Escherichia coli O157:H7 gastroenteritis and the hemolytic uremic syndrome
Escherichia coli O157:H7 gastroenteritis and the hemolytic uremic syndrome: an emerging infectious disease. Besser RE, Griffin PM, Slutsker L. Annual Review of Medicine 1999;50:355-367.
Escherichia coli O157:H7 is an increasingly common cause of a variety of illnesses, including bloody diarrhea and the hemolytic uremic syndrome (HUS). This emerging infectious agent was first identified in 1982 and has been isolated with increasing frequency since then. This chapter reviews the epidemiology, clinical spectrum, diagnosis, treatment, and prevention of infections with E. coli O157:H7. Infection with E. coli O157H:7 usually resolves after one week with no obvious sequelae. However, 5-10% of children with E. coli O157:H7 will develop HUS. HUS consists of the triad of microangiopathic hemolytic anemia, thrombocytopenia, and oliguric renal failure. An incomplete form of HUS has been reported, in which some of the classic features are missing. Central nervous system (CNS) manifestations, including lethargy, seizures, coma, and hemiparesis, occur in 30% of patients with HUS. Reported risk factors for the development of HUS have included extremes of age, female gender, absent or weak P1 antigen expression by red blood cells, bloody diarrhea, fever, elevated white blood cell count, and treatment with antimotility or antimicrobial agent; however, although not all of these risk factors have been confirmed. Antimicrobial agents have no proven value in the treatment of E. coli O157:H7 infections, but no randomized clinical trials of the early use of these agents in this disease have been performed. Until these studies have been carried out, the authors suggest that it may be prudent to avoid the use of antimicrobial agents in E. coli O157:H7 infections. A novel approach to the prevention of HUS involves a Shiga toxin-binding agent early in the course of the infection, although initial trials have shown a significant reduction in the rate of progression to HUS. Antimotility agents are discouraged as these drugs may increase the risk of HUS in patients infected with E. coli O157:H7 and increase the risk of neurologic manifestations in patients with HUS. Treatment with HUS is supportive, with particular attention to the management of fluids and electrolytes. Numerous other therapies have been tried but are of unproven efficacy.