Venous Thrombosis Flashcards
What are examples of arterial thrombotic events?
Coronary
Cerebral
Peripheral
What are venous thrombotic events?
DVT
Pulmonary embolism
Why does arterial thrombosis occur?
High pressure system
Atherosclerosis
Platelet rich thrombus
How do we treat arterial thrombosis?
Aspirin and other anti-platelet drugs
Modify risk factors for atherosclerosis
How does venous thrombosis occur?
Low pressure system
Platelets not activated
Activates coagulation cascade - rich in fibrin clot
What is Virchow’s triad in venous thrombosis?
Blood stasis
Vessel wall damage
Hypercoagulability
How can we treat venous thrombosis?
Heparin
Warfarin
New oral anticoagulants
What are signs of DVT?
Hot, swollen, painful limb
Pitting oedema
What are signs of pulmonary embolism?
Pulmonary infarction
Pleuritic chest pain
CV collapse / death
Hypoxia
Right heart strain
What are risk factors for venous thromboembolism?
Age
Obesity
Pregnancy
Oestrogen therapy
Previous DVT or PE
Trauma / Surgery
Malignancy
Paralysis
Infection
Thrombophilia
Puerperium
What factors make you more hyper coagulable?
Age
Pregnancy
Oestrogen therapy
Trauma / Surgery
Malignancy
Infection
Thrombophilia
Age, pregnancy, oestrogen therapy, trauma / surgery, malignancy and infection are associated with what which can lead to hyper coagulability?
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
What are potential mechanisms of thrombophilia?
Increased coagulation activity (platelet plug formation; fibrin clot formation)
Decreased fibrinolytic activity
Decreased anticoagulation 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
What are the main hereditary thrombophilias?
Factor V leiden
Prothrombin 20210 mutation
Antithrombin deficiency
Protein C deficiency
Protein S deficiency
When do we consider thrombophilia screening?
Venous thrombosis <45 years old
Recurrent venus thrombosis
Unusual venous thrombosis
FH of venous thrombosis
FH of thrombophilia
How do we manage 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 evens
What history findings are important to assess risk of recurrent thrombosis?
Hx of previous thrombosis
Sponantenous thrombosis rather than acquired transient risk factor (e.g. immobility or surgery)
FH
Thrombophilia screen results
What are causes of acquired thrombophilia?
Antiphospholipid antibody syndrome
Stronger risk factor for thrombosis than the hereditary thrombophilias
What are features of antiphospholipid syndrome?
Recurrent thromboses - arterial (including TIAs), venous
Recurrent fetal loss
Mild thrombocytopenia
What is the pathogenesis of antiphospholipid syndrome?
Antibodies lead to a conformational change in beta2 glycoprotein 1 (a protein with unknown function in health) which leads to activation of 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
Also known as lupus anticoagulants
What are conditions associated with antiphospholipid antibodies?
Autoimmune disorders
Lymphoproliferative disorders
Viral infections
Drugs
Primary
