Haemolytic uraemic syndrome

• Haemolytic uraemic syndrome:

  • Thrombosis in small blood vessels throughout the body
  • Usually triggered by Shiga toxins from either E. coli O157 or Shigella
  • Most often affects children following an acute episode of gastroenteritis
  • Antibiotics and antidiarrheal medication used to treat gastroenteritis caused by E.coli or shigella increase the risk of HUS
• HUS leads to the classic triad of:

  • Microangiopathic haemolytic anaemia
  • Acute kidney injury
  • Thrombocytopenia - formation of blood clots consumes platelets
• Microangiopathic haemolytic anaemia:

  • Haemolysis due to pathology in the small vessels - microangiopathy
  • Thrombi partially obstruct the small blood vessels and churn the red blood cells as they pass through, causing them to rupture
• Onset of symptoms:

  • HUS tends to develop around a week after the onset of diarrhoea
  • E. coli O157 and Shigella cause gastroenteritis
  • Diarrhoea is the first symptom, which usually turns bloody within 3 days
• Features of HUS:

  • Fever
  • Abdominal pain
  • Lethargy
  • Pallor
  • Oliguria
  • Haematuria
  • Hypertension (renal failure)
  • Bruising (thrombocytopenia)
  • Jaundice (haemolysis)
  • Confusion
• Stool tests (culture and PCR) establish the causative organism
• Management:

  • Medical emergency needing hospital admission
  • Supportive treatment with
  • Fluid and electrolyte replacement
  • Management of severe hypertension
  • Blood transfusions for severe anaemia
  • Haemodialysis for severe renal failure
• Prognosis:

  • Self-limiting
  • Most patients fully recover with good supportive care