Hemolytic Uremic Syndrome

For 24 hours, a 62-year-old woman had had severe weakness, abdominal pain, and watery diarrhea that had become bloody in the past 12 hours. She had no significant medical history.The patient was confused anddehydrated. Tenderness was noted inthe right lower quadrant. Temperaturewas 37.2C (99F); heart rate,110 beats per minute; and blood pressure,90/50 mm Hg. Her white bloodcell count was 15,000/μL; plateletcount, 60,000/μL; hemoglobin, 9g/dL; hematocrit, 32%; blood urea nitrogenlevel, 85 mg/dL; serum creatinine, 2.1 mg/dL; andfibrinogen, 95 mg/dL. D-dimer levels were increased.A peripheral blood smear revealed schistocytes, fragmentedand deformed erythrocytes, and thrombocytopenia(A). Colonoscopy findings showed friable, inflamed,and hemorrhagic mucosa (B). A stool culture was positivefor Escherichia coli, serotype 0157:H7.Lucia C. Fry, MD, and Klaus E. Mnkemller, MD,of Chandler, Ariz, diagnosed enterohemorrhagic colitiswith hemolytic uremic syndrome. This syndrome is characterizedby acute hemolytic anemia, renal failure withuremia, and disseminated intravascular coagulation. It occursin patients with enterohemorrhagic E coli or shigellosisintestinal infection.¹Outbreaks of bloody colitis secondary to infectionwith the specific serotype of E coli 0157:H7 have beenlinked to inadequately cooked ground-beef hamburgers atfast-food restaurants.² Most subsequent outbreaks havebeen associated with ingestion of contaminated food ormilk, but person-to-person transmission can also occur.³Children younger than 5 years and elderly persons are particularlysusceptible to this syndrome.³ The pathophysiologyprimarily involves toxin-induced damage (caused byShiga-like toxins), which produces endothelial alterationsand thrombosis that finally results in intestinal ischemia.There is no evidence that early antimicrobial therapyfor enteric infection prevents hemolytic uremic syndrome.Treatment consists of hemodialysis and supportivecare. Because this syndrome isusually self-limited, antibiotics arenot recommended.This patient received supportivetherapy with intravenous fluids andelectrolyte replacement. During thenext 24 hours, her condition improvedmarkedly and she did not requireplasmapheresis or hemodialysis.