Venous thrombosis Flashcards
Venous drainage is a:
low/high pressure system
low pressure
In the veins, platelets/coagulation cascade is activated
platelets are NOT activated
coagulation cascade IS activated
platelet/fibrin rich clots form in veins
fibrin rich
what are the features of Virchow’s triad
stasis
vessel damage
hypercoaguability
risk factors for stasis
older age obesity paralysis pregnancy trauma/surgery malignancy
risk factors for vessel damage
previous thrombosis
older age
risk factors for hypercoaguability
Anything that increases clotting factors: malignancy age pregnancy and puerperium oestrogen therapy trauma/surgery infection thrombophilia
what is the overall pathophysiology of thrombophilias
decreased levels of natural anticoagulant defences
haemostasis and clot formation is not switched off
define thrombophilia
hereditary/acquired disorders of haemostasis which are likely to predispose to thrombosis
what are mechanisms behind thrombophilias
increased platelet or fibrin formation
decreased fibrinolysis or coagulation defences
what are the bodies natural anticoagulants and their functions
antithrombin - switches off thrombin
Protein C+S - switch off factors V + VIII
what are hereditary thrombophilias
genetic defects which increase the tendency to form abnormal, premature and recurrent thromboses
list causes of hereditary thrombophilias
Factor V Leiden Prothrombin 20210 mutation Anti thrombin deficiency Protein C deficiency Protein S deficiency
how does Factor V Leiden cause thrombophilia
impairs ability of protein C+S to switch off factor V
how does Prothrombin 20210 mutation cause thrombophilia
increases expression of prothrombin via F2 gene mutation
how does antithrombin deficiency cause thrombophilia
failure to switch off thrombin
how does Protein C+S deficiency cause thrombophilia
inability to switch off factor V and VIII
who would you consider doing a hereditary hrombophilia screen in
venous thrombosis <45 y/o recurrent thrombosis unusual thrombosis FH thrombosis FH thrombophilia
what is the management of hereditary thrombophilias
avoid risk factors
short term prophylaxis
short term anticoagulation
long term anticoagulation
Risk factors for recurrent thrombosis
which one is most important
previous thrombosis - most important
spontaneous thrombosis with no risk factors
FH
screening results
what is a cause of acquired thrombophilia
anti phospholipid syndrome APLS
what is APLS
autoimmune condition attacking B2 glycoprotein 1 which increases risk of arterial AND venous thrombosis by activating primary and secondary haemostasis as well as causing damage to vessel walls
clinical features of APLS
recurrent thrombosis (arterial and venous)
recurrent foetal loss
mild thrombocytopaenia
investigations for APLS
antibodies: anti-B2glycoprotein, lupus anticoagulant, anti-cardiolipin
APTT prolonged
which conditions are associated with APLS
SLE
lymphoproliferative disorders
viral - EBV
drugs
management of APLS
antiplatelets AND anticoagulants
because of thrombosis risk in arteries and veins
