Expansion
Widespread activation of coagulation consumes factors and platelets, causing both thrombosis and bleeding
Expansion
Mechanism
- A trigger releases tissue factor into the circulation
- Widespread thrombin generation causes microvascular thrombosis and organ failure
- Consumption of clotting factors and platelets
- Secondary fibrinolysis with fibrin degradation products, which themselves impair clotting
- The result is simultaneous thrombosis and bleeding
Triggers: sepsis (especially Gram negative), major trauma, burns, obstetric catastrophe (abruption, amniotic fluid embolism, retained products), malignancy (especially acute promyelocytic leukaemia), severe transfusion reaction, snake bite.
Laboratory picture
- Prolonged PT and APTT
- Low platelets
- Low fibrinogen (a useful discriminator, since it is an acute phase protein and would otherwise rise)
- High D-dimer and fibrin degradation products
- Schistocytes on the film from microangiopathic haemolysis
Treatment is of the underlying cause, with blood product support guided by bleeding rather than by numbers alone. Heparin is reserved for predominantly thrombotic presentations.