Epidemiology

  • Incidence: 1.50 cases per 100,000 person-years
  • Peak incidence: 1-5 years
  • Sex ratio: 1:1
<1 1-5 6+ 16+ 30+ 40+ 50+ 60+ 70+ 80+

Pathophysiology

Most cases are secondary (termed 'typical HUS'):
  • classically Shiga toxin-producing Escherichia coli (STEC) 0157:H7 ('verotoxigenic', 'enterohaemorrhagic'). This is the most common cause in children, accounting for over 90% of cases
  • pneumococcal infection
  • HIV
  • rare: systemic lupus erythematosus, drugs, cancer

Primary HUS ('atypical') is due to complement dysregulation.

Clinical features

Haemolytic uraemic syndrome is generally seen in young children and produces a triad of:

Investigations

Investigations
  • full blood count: anaemia, thrombocytopaenia, fragmented blood film
  • U&E: acute kidney injury
  • stool culture

Management

Management
  • treatment is supportive e.g. Fluids, blood transfusion and dialysis if required
  • there is no role for antibiotics, despite the preceding diarrhoeal illness in many patients
  • the indications for plasma exchange in HUS are complicated. As a general rule plasma exchange is reserved for severe cases of HUS not associated with diarrhoea
  • eculizumab (a C5 inhibitor monoclonal antibody) has evidence of greater efficiency than plasma exchange alone in the treatment of adult atypical HUS