Thrombosis and Embolism (haematology) Flashcards
What are the three natural anticoagulants we have?
Antithrombin
Protein C system
Tissue factor pathway inhibitor (TFPI)
What are the causes of thrombosis?
-Stasis
-Vessel wall injury
-Hypercoagulability
What type of clot forms in:
1. Veins
2. Arteries
- Red clot (rich in fibrin and trapped RBCs.)
- White clot (rich in platelets)
What substance is used to treat deep vein clotting?
Warfarin
How do we treat the two types of clots?
- Venous clot- treatment is medication that interrupts with the coagulation cascade, such as warfarin.
- Arterial clot- treatment is drugs that block platelet activation.
What are the risk factors for arterial thrombosis? (7)
-Elevated factor VIII
-Elevated fibrinogen levels
-Lupus anticoagulant
-Polycythaemia rubra vera
-Essential thrombocythaemia
-Diabetes, hypertension
-Smoking
What are the causes of venous thrombosis? (3)
•Thrombophilia (easy formation of blood clots)
•Vessel wall injury (causes plaque formation and plaque rupture)
•Reduced flow (immobility, obesity/pregnancy, limb paralysis, long distance travel).
What are the causes of:
1. Acquired thrombophilia
2. Inherited thrombophilia
- Pregnancy, contraceptive pill, malignancy, lupus anticoagulant.
- Factor V leiden, protein C deficiency, protein S deficiency, prothrombin mutation, antithrombin deficiency.
What are the clinical presentations of thrombosis? (2)
Arterial thrombosis- ischaemia (e.g MI)
Venous theombosis- stasis and blockage (e.g deep vein thrombosis)
Treatment for:
1. Arterial thrombosis (5)
2. Venous thrombosis (3)
- Fibrinolysis, streptokinase, urokinase, TPA as well as antiplatelet therapy.
- Warfarin, heparin, and new anticoagulants.
Which coagulation factors does warfarin inhibit?
Vitamin K dependent, II, VII, IX and X.
Which coagulation factors does heparin inhibit?
- factor II and X.
What is the mechanism of action for warfarin? (3)
Warfarin inhibits the enzyme responsible for the activation of vitamin K.
-Inhibits the activation of vitamin K dependent factors (II, VII, , IX and X) and protein C, S.
-Decreases coagulation.
What are the indications of warfarin:
1. Good evidence
2. Limited evidence
- Embolic stroke, DVT, atrial fibrillations.
- Congestive heart failure, dilated cardiomyopathy, non-embolic stroke, peripheral vascular diseases.
What major risk is associated with using warfarin especially in the elderly?
Risk of bleeding