Venous thrombosis Flashcards
Where can thrombotic events occur?
Arterial - coronary, cerebral, peripheral
Venous - DVT, PE
What leads to arterial thrombosis?
Atherosclerosis
What is used to treat atherosclerosis?
Aspirin, anti-platelet drugs
What are the 3 components of Virchow’s triad?
Stasis
Hypercoagulability
Vessel wall damage / injury
What is the treatment of venous thrombosis?
Heparin / warfarin historically
New oral anticoagulants becoming more common
What is the typical clinical presentation of a DVT?
Patient discomfort is the main symptom
Limb may fell hot, swollen and tender (particularly the calf)
Pitting oedema may be present
What is the typical clinical presentation of a PE?
Pleuritic chest pain, hypoxia, right heart strain
Pulmonary infarction and cardiovascular collapse / death may occur
Give examples of risk factors for thromboembolism?
*Think of Virchow’s triad
Less mobile: age, obesity, period of immobility after surgery, paralysis
Vessels: pregnancy, previous DVT/PE, age
Hypercoagulability: malignancy, infection, thrombophilia, age, oestrogen therapy - combined oral contraceptive, puerperium
What is hypercoagulability associated with?
Release of tissue factor, raised vWF and factor VIII
What is thrombophilia?
Familial or acquired disorders of the haemostatic mechanism which are likely to predispose to thrombosis
Give 3 potential mechanisms of thrombophilia?
Increased coagulation activity
Decreased fibrinolytic activity
Decreased anticoagulant activity
What are hereditary thrombophilias?
A group of genetic defects in which affected individuals have an increased tendency to develop premature, unusual and recurrent thromboses
Give an example of a hereditary thrombophilia?
Protein C deficiency
Protein S deficiency
Antithrombin deficiency
When should hereditary thrombophilia screening be considered?
Family history of thrombophilia / venous thrombosis
Unusual / recurrent venous thrombosis
Venous thrombosis in a patient younger than 45 years old
How is hereditary thrombophilia managed?
Patient education / advice
Short term prophylaxis
Short / long term anticoagulation
What is short term prophylaxis given for in hereditary thrombophilia?
To prevent thrombotic events during periods of known risk
When is long term anticoagulation given in hereditary thrombophilia?
If the patient has recurrent thrombotic events
What should be carefully considered prior to long term anticoagulation?
The balance between the risk of recurrent thrombosis and the risk of serious haemorrhage
What is a well known example of an acquired autoimmune thrombophilia?
Antiphospholipid antibody syndrome
Give 3 features of antiphospholipid antibody syndrome?
Recurrent thromboses
Recurrent foetal loss
Mild thrombocytopenia
What pathogenesis occurs in patients with antiphospholipid antibody syndrome?
Antibodies lead to a conformational change in beta2 glycoprotein 1
This activates both primary and secondary haemostasis and vessel wall abnormalities
What are antiphospholipid antibodies?
Autoantibodies which have specificity for anionic phospholipids and which prolong phospholipid dependent coagulation tests in vitro
How is antiphospholipid antibody syndrome treated?
Aspirin and warfarin
What 2 factors can be tested for in a suspected inherited thrombophilia?
Factor V
Factor II (prothrombin)
