Venous Thrombosis Flashcards
What are the types of thrombotic events?
Arterial = coronary, cerebral, peripheral Venous = DVT, PE
What kind of pressure systems are the vascular systems?
Arterial = high pressure Venous = low pressure
What are the features of arterial thromboses?
Atherosclerosis = cholesterol pushed into vessel walls
Platelet rich thrombus
What is the treatment of arterial thrombosis?
Aspirin and other anti-platelets = modify risk factors for atherosclerosis
What are the features of venous thrombosis?
No atherosclerosis as low pressure
Activates coagulation cascade = clot rich in fibrin
Platelets not activated
What are the risk factors for venous thrombosis?
Stasis, vessel wall (valve degeneration), hypercoagulability
What are the symptoms of a DVT?
Hot, swollen and tender limb
Pitting oedema
What can a DVT lead to?
May embolise and cause a PE = pulmonary infarction, pleuritic chest pain, CV collapse, right heart failure, hypoxia
What age group are VTEs more common in?
Older patients = risk increases with age
What are the risk factors for VTE?
Age, obesity, pregnancy, puerperium, oestrogen therapy, previous DVT/PE, trauma/surgery, malignancy, paralysis, infection, thrombophilia
What is hypercoagulability associated with?
Tissue factor release, raised vWF and factor VIII
What are thrombophilias?
Disorders of haemostatic mechanism which are likely to predispose to thrombosis
What are the mechanisms of thrombophilia?
Increased coagulation activity = primary or secondary haemostasis
Decreased fibrinolytic activity = rare
Decreased anticoagulant activity = most common
What is the co-factor of protein C?
Protein S
What causes factor V leiden?
Single base pair change = factor V works normally in haemostasis but doesn’t bind as well to protein C for anticoagulation
What are the causes of hereditary thrombophilia?
Factor V leiden, prothrombin 20210 mutation, antithrombin deficiency, protein C deficiency, protein S deficiency
When would you suspect hereditary thrombophilias?
Unprovoked venous thrombosis <45 years old
Recurrent venous thrombosis
Unusual venous thrombosis
Family history of thrombophilia or venous thrombosis
What is the management of hereditary thrombophilia?
Advice on avoiding risk
Short term prophylaxis to prevent thrombotic events during periods of known risk
Short term anticoagulation to treat thrombotic events
Long term anticoagulation if recurrent thrombotic events
What increases risk of recurrent thrombosis?
History of previous thrombosis = biggest risk factor
Spontaneous thrombosis rather than acquired transient risk factor
Family history or thrombophilia
What is a cause of acquired thrombophilia?
Antiphospholipid antibody syndrome
Is antiphospholipid antibody syndrome or hereditary thrombophilia a stronger risk factor for thrombosis?
Antiphospholipid antibody syndrome
What are the features of antiphospholipid antibody syndrome?
Recurrent arterial and venous thromboses
Recurrent foetal loss
Mild thrombocytopenia
What causes antiphospholipid antibody syndrome?
Antibodies cause change in B2 glycoprotein 1 = leads to activation of both primary and secondary haemostasis plus vessel wall abnormalities
What are the features of the autoantibodies present in antiphospholipid antibody syndrome?
Specific for anionic phospholipids
Prolong antiphospholipid dependent coagulation test in vitro
Also known as lupus anticoagulants
