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...