Sunday, 31 October 2010

MRCP revision battle 38.5: Thrombotic thrombocytopenic purpura

Thrombotic thrombocytopenic purpura is a condition in which large multimers of Von Willebrand's factor clump platelets together, activating the coagulation system, forming fibrin strands and causing microangiopathic haemolytic anaemia (MAHA).

The 5 key features are:
  • Thrombocytopenia
  • Fever
  • Fluctating CNS signs (visual disturbance, fits, hemiparesis)
  • MAHA
  • Renal failure

Adult females are most commonly affected

The cause is often unknown.  Implicated factors include:
  • drugs - clopidogrel, ciclosporin, COC
  • pregnancy
  • HIV
  • SLE

 Treatment is:
  • plasma exchange
  • IV vincristine  (promotes premature release of platelets from marrow)
  • steroids

Next up... more microangiopathic haemolytic anaemia...