Hemolytic uremic syndrome

Background

• Similar to but different from TTP (which is more common in adults)
• Most cases occur in children <10yr (2/3 of cases in <5yr)
• Most cases due to E. coli O157:H7 infection
  • Shiga toxin may induce autoantibody to CD36 (found on endothelial cells and platelets)
  • May also be caused by shigella, yersinia, campylobacter, salmonella
• Types:
  • Typical
    • Occurs 2-14d after development of infectious diarrhea (bloody, no fever)
  • Atypical
    • Occurs in older children and adults
    • Extrarenal involvement is common (difficult to distinguish from TTP)
    • May be caused by atypical pathogens (EBV, S. pneumo) or immunosuppression

Clinical Features

1. Triad:
   1. Acute renal failure
      1. Oliguria
   2. Thrombocytopenia
   3. Microangiopathic hemolytic anemia
2. Enteritis
   1. N/V, diarrhea (usually bloody), +/- fever
3. Hyperglycemia
   1. Pancreatic beta-cell dealth due to microthrombi within pancreas

• Within a week develops pallor, oliguria, lethargy, sz, encephalopathy

DDx

• Acute gastroenteritis
• Appendicitis
• Colitis
• Intussusception
• IBD
• Perforation
• DIC
• TTP
• SLE

Work-Up

• CBC
  • WBC may be elevated
  • Anemia
    • Schistocytes
  • Thrombocytopenia
• Stool tests
  • Shiga toxin, E. coli O157:H7 test
• UA
  • Hematuria, casts
• LFT
  • Increased bilirubin
• Chemistry
  • Creatinine, hyperkalemia (renal failure)

Treatment

• Supportive care
  • Fluid for hypovolemia
  • Transfusion for anemia
• Abx are not indicated
• Antimotility agents are contraindicated
• Platelets are contraindicated
• Emergency dialysis for acute renal failure

Disposition

• Admit

Source

Tintinalli