Thrombotic Thrombocytopenic Purpura and Haemolytic-Uraemic Syndrome (Congenital and Acquired)

Research output: Chapter in Book/Report/Conference proceedingChapter


Thrombocytopenia and microangiopathic haemolytic anemia are the hallmark of the thrombotic microangiopathies (TMAs) thrombotic thrombocytopenic purpura (TTP) and haemolytic uraemic syndrome (HUS). TTP, congenital or autoimmune, is mainly caused by the plasma deficiency of ADAMTS13, owing to gene mutations or inactivating autoantibodies. Typical HUS, called STEC-HUS, accounts for more than 90% of cases and is usually caused by infections with Shiga-Toxin-producing Escherichia Coli. The rarest atypical HUS is associated with complement dysregulation in up to half of the cases, owing to the inherited or acquired deficiency of factor H or other complement regulatory proteins. Until recently the distinction between these TMAs was almost exclusively based on clinical grounds, the term TTP being used for cases with predominant neurological involvement and atypical HUS identifying patients with more severe renal injury. However currently used clinical criteria (prevailing neurological or renal involvement) and laboratory data (ADAMTS13 activity) may not easily distinguish TTP from atypical HUS. The differential diagnosis has clinical implications, because plasma exchange, the treatment of choice in TTP, is much less effective in atypical HUS, which shows dramatic short-and long-term benefits from intravenous eculizumab, an antibody that inhibits complement activation.

Original languageEnglish
Title of host publicationPostgraduate Haematology: Seventh Edition
PublisherWiley Blackwell
Number of pages12
ISBN (Electronic)9781118853771
ISBN (Print)9781118854327
Publication statusPublished - Nov 6 2015


  • ADAMTS13
  • Complement system
  • Haemolytic uraemic syndrome
  • Immunosuppressive treatment
  • Plasma therapy
  • Thrombotic thrombocytopenic purpura

ASJC Scopus subject areas

  • Medicine(all)


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