	A form of MAHA
Etiology	See below
Epidemiology	Shiga toxin producing HUS - most common age <5
Clinical presentation	bloody diarrhoea, fever, abdo pain, haemoglobinuria, AKI (oliguria)
Pathogenesis	Damage to glomerular epithelium = thrombotic microangiopathy
Diagnostic investigations	FBC - Thrombocytopenia U+E ADAMTS-13
Management	Notifiable disease. Shiga toxin-producing HUS: supportive, including RRT etc. Atypical HUS: ➥ eculizumab (binds to C5 and blocks terminal complement activation) ➥ PLEX ➥ treat as asplenic, e.g. meningococcal prophylaxis HUS associated with S. pneumoniae: ➥ no PLEX - naturally occurring abs against Thomsen-Friedenreich antigen can worsen agglutination (Cochran et al 2004) Abx can induce expression + release of Shiga toxin!

etiology

Infectious agents
- Shigatoxin producers:
  - Enterohaemorrhagic Escherichia coli (EHEC)
  - Shigella dysenteriae
  - Citrobacter freundii
- Streptococcus pneumoniae
- Pseudomonas aeruginosa
- Enteroviruses (Coxsackie A and B, Echovirus)
- HIV
- CMV
Complement dysregulation ("atypical" HUS)
- Congenital mutations in regulatory complement proteins, eg. factor H, factor I, MCP, C3, factor B, clusterin, thrombomodulin, diacylglycerol kinase-e (DGKE)
- Acquired, eg. antibody to Factor H
Autoimmune
- SLE
- Antiphospholipid syndrome
- Scleroderma
Peripartum
- HELLP and HUS are related
Solid organ and bone marrow transplantation
secondary HUS after exposure to drugs (e.g. ciclosporin...)

sources/links