Thrombosis and Risk Factors Flashcards
Risk factors for thrombosis
Virchow’s triad- flow, composition or vessel wall
Outline the brief pathology of arterial thrombosis
Atherosclerosis, rupture of atheromatous plaque, endothelial injury, platelet aggregation
Describe the composition of thrombi in venous thrombosis
Pred. fibrin and RBCs, less platelets
Complication of venous thrombosis
Venous thromboembolism (VTE)
Treatment for VTE
Low molecular weight heparin e.g. fondaparinux Newer anticoagulants e.g: Xa inhibitors rivaroxaban IIa inhibitors dabigatran Compression stockings
Natural procoagulants
Clotting factors
Natural anticoagulants
Antithrombin III
Proteins C+S
Fibrinolytics
How does heparin work?
Increases antithrombin activity
Does LMWH predominantly target Xa or IIa?
Xa
Does fondaparinoux predominantly target Xa or IIa?
entirely Xa
Diagnostic test for VTE
Wells score
D-dimer test
Ultrasound
VQ scan
What test is used to measure the breakdown products of fibrin clots- specific to plasmin acting on fibrin
D-dimer
What does the VQ scan pick up in PE?
Ventilation:perfusion mismatch
What are the advantages of novel anticoagulants?
Dose is uniform for post patients and rapid onset
Target INR
2.5
Familial or acquired disorder of the haemostatic mechanism likely to predispose to thrombosis
Thrombophilias
Heritable thrombophilias
Antithrombin def Protein C def Protein S def FV leiden-activated protein C resistance Prothrombin 20210A Dysfibrinogenaemia
Prothrombin 20210A
Too much prothrombin
An example of an acquired thrombophilia
Antiphospholipid syndrome- autoimmune, hypercoagulable state
Clinical features of thrombophilia
VTE
Superfical thrombophlebitis
Thrombosis of cerebral, axillary, portal and mesenteric veins
Coumarin induced skin necrosis (PC deficiency)
Obstetic complications- fetal wastage- thrombosis of placental circulation
What is the function of protein C
Breaksdown Va and VIIIa
What is the function of protein S
Cofactor for protein C
Describe factor V leiden
Va resistant to protein C
Examples of hypercoagulable state
FV leiden
Pill
Pregnancy
Immobility
