Flashcards in Bleeding and Thrombosis Deck (54)
List causes of failure of platelet plug formation (failure of primary haemostasis)
Low platelet count (thrombocytopenia)
Impaired platelet function
Von Willbrand Factor disease
What is the main vascular cause of failed primary haemostasis?
Vasculitis e.g. Henoch-Schonlein purpura
Thrombocytopenia can be due to what 2 factors?
Reduced platelet production (marrow disorder)
Increased platelet destruction
List the main causes of platelet destruction
Von Willebrand Factor deficiency is mainly hereditary and follows what inheritance pattern?
List causes of failure of fibrin clot formation (failure of secondary haemostasis)
Multiple clotting factor deficiency
Single clotting factor deficiency
List causes of multiple clotting factor deficiency
Vitamin K deficiency
What is the main cause of single clotting factor deficiency?
Which clotting factors are carboxylated (activated) by vitamin K?
List causes of vitamin K deficiency
Poor dietary intake
Haemorrhagic disease of newborn
What is disseminated intravascular coagulation (DIC)?
Excessive activation of the haemostatic system, causing depletion of all clotting factors
What are the main signs of DIC?
What are the main screening tests/investigations for haemostasis?
List the main causes of DIC
How is DIC treated?
Treat underlying cause
Replace clotting factors
What pattern of inheritance does haemophilia follow?
What are the two types of haemophilia? Which is more common?
Haemophilia A (VIII deficiency)
Haemophilia B (IX deficiency)
A is more common than B
Where does bleeding usually occur in haemophilia?
Is haemophilia a disorder of primary or secondary haemostasis?
Prothrombin time is usually normal in a haemophiliac. True/False?
Isolated prolonged APT time
What is the main cause of arterial thrombosis?
How is atherosclerosis treated?
Venous thrombosis is caused by Virchow's triad. List the components of this triad
Vessel wall damage
Stasis of blood flow
What is the risk of a deep vein thrombosis in the leg?
Clot can form and end up in pulmonary circulation, causing pulmonary embolism
List risk factors for venous thromboembolism
Oestrogen therapy (OCP)
What are the main mechanisms of thrombophilia?
Increased coagulation activity
Decreased fibrinolytic activity
Decreased anticoagulant activity
What are the main naturally occuring anticoagulants?
Serine protease inhibitors (antithrombin)
Protein C and S
What is Factor V Leiden?
Variant of factor V that cannot be inhibited as effectively - increases risk of venous thrombosis due to less anticoagulation
List the main hereditary thrombophilias
Factor V Leiden
Protein C and S deficiency