Venous Thrombosis Flashcards
Venous thrombosis types (2)
DVT,
PE
Arterial thrombosis types
coronary,
cerebral,
peripheral
Arterial thrombosis formation and clot type
piece of arthersclerosis breaks off, collagen exposed and then platelet rich thrombus comes and occludes vessel
Treatment for arterial thrombosis
aspirin and other anti-platelets drugs
Arterial high pressure/low pressure venous high/low pressure
venous low
Venous thrombosis formation and clot type
valves deteriorate meaning blood stasis which activates coagulation cascade so platelets not activated but clot is rich in fibrin
Virchows triad and venous thrombosis
stasis,
vessel wall (degenerating valves e.g. old age, previous DVT)
hypercoagulability (higher levels of acute phase proteins e.g. CRP, VIII, TF, vWF due to inflammation etc )
Treatment for venous thrombosis
heparin,
warfarin,
new oral anticoagulants
Highest risk factor for DVT?
history of previous DVT
DVT presentation
hot, swollen, tender limb,
pitting oedema
PE pattern of events including heart
pulmonary infarction, pleuritic chest pain, Cardiovascular collapse/death, hypoxia, right heart strain
Risk of VTE
1/1000 per year
lifetime risk of VTE
2.5%
Risk factors for Venous thromboembolism (11)
age, obesity, pregnancy, puerperium, oestrogen therapy, previous DVT/PE, trauma/surgery, malignancy, paralysis, infection, thrombophilia
Clotting factors rise/fall in pregnancy to reduce bleeding?
rise
Which components of normal haemostatic system is most commonly dysfunctional in thrombophilia?
anticoagulant defences abnormal
Which 7 risk factors for VT are under stasis
age, obesity, pregnancy, trauma/surgery, malignancy, paralysis, previous DVT/PE
Which 2 particular risk factors fall under vessel wall damage?
age,
previous DVT/PE
Which 8 risk factors fall under hypercoagulability?
age, pregnancy, puerperium, oestrogen therapy, trauma/surgery, malignancy, infection, thrombophilia
Hypercoagulability are associate with release of what and raised what? (3)
release of tissue factor,
raised vWF and factor VIII
Thrombophilia definition?
familial or acquired disorders of the haemostatic mechanism which are likely to predispose to thrombosis
What is the most common mechanism of thrombphilia?
Decreased anticoagulant activity
What type of naturally occurring anticoagulant is anti-thrombin?
Serine protease inhibitor
What does anti-thrombin switch off?
thrombin, TF/VII, V/X. VII, IX
Which is main protein and which is cofactor - protein c and protein s?
Protein C is main one and protein s is cofactor
How do protein c and protein s switch of clotting pathway?
When haemostasis achieved thrombin binds to thrombomodulin which changes function from being protein involved in forming fibrin to switch on protein c and s. these inhibit factor V and factor VIII
Commonest inherited blood clotting disorder? How does it cause VT?
Factor V Leiden - factor V slightly mutated, works normally but isn’t switched off as efficiently by protein c/s and so have x5 increased risk of VT
List the 5 hereditary thrombophilias?
factor V leiden, prothrombin 20210 mutation, antithrombin deficiency, Protein C deficiency, protein S deficiency
In what cases would you consider hereditary thrombophilia screening? (5)
venous thrombosis <45 years, recurrent venous thrombosis, unusual venous thrombosis, FH of venous thrombosis, FH of thrombophilia
Management of hereditary thrombophilia? (4)
advice on avoiding risk,
short term prophylaxis for periods of risk,
short term anticoagulation to treat thrombotic events,
long term Anticoagulation if recurrent thrombotic events
When do you give long term anticoagulation to those with hereditary thrombophilia? What are you trying to balance?
if RECURRENT thrombotic events,
risk of recurrent thrombosis vs risk of serious haemorrhage
Clinical history is less important than the results if thrombophilia screening are positive. T/F?
False! Clinical history much more important
List factors from clinical history that indicate higher risk of recurrent thrombosis starting at highest risk (4)
history of previous thrombosis,
spontaneous thrombosis rather than acquired transient risk factor,
FH,
thrombophilia screen results
Give an example of an acquired thrombophilia?
antiphospholipid antibody syndrome
APS is a stronger risk factor for thrombosis than the hereditary thrombophilias. T/F?
True
List 3 main features of APS
recurrent thromboses (arterial and venous),
recurrent fetal loss,
mild thrombocytopenia
Pathogenesis of APS
Antibodies lead to a conformational change in β2 glycoprotein 1 (a protein with unknown function in health) which leads to activation of both primary and secondary haemostasis and vessel wall abnormalities.
antiphospholipid antibodies
listen to let
screening tests for APS
listen to lec
investigations for aps (3)
Levels of aCL, anti-beta2 GPI or lupus anticoagulant (LA) on two occasions at least 12 weeks apart,
FBC: thrombocytopenia, haemolytic anaemia,
Clotting screen
List 5 conditions associated with antiphospholipid antibodies
autoimmune disorders, lymphoproliferative disorders, viral infections, drugs, primary (listen to lector's)
Treatment of APS
aspirin warfarin (listen to lector’s)
