Thrombic disorders Flashcards
What are the elements of haemostatsis?
Primary haemostasis
Blood coagulation
Fibrinolysis
What happens in primary haemostats?
Vasoconstriction
Platelet adhesion
Platelet aggregation
What happens in coagulation?
Insoluble fibrin formation
Fibrin cross-linking
What is a thrombus?
Clot arising in wrong place
What is a thromboembolism?
Movement of clot along a vessel
What is Virchow’s Triad?
Stasis
Hypercoagulability
Vessel damage
What can cause stasis?
Bed rest
Travel
What can cause hypercoagulabiity?
Pregnancy
Trauma
What can cause vessel damage?
Atherosclerosis
What are the types of thrombus?
Arterial
Venous
Microvascular
What is an arterial thrombosis made up from?
Platelets and fibrin
What does arterial thrombus result in?
Ischaemia and infarction
Usually secondary to atherosclerosis
What are examples of arterial thromboembolism?
Coronary thrombosis: MI/unstable angina
Cerebrovascular thromboembolism: stroke/transient ichaemia
Peripheral embolism: limb ischaemia
What are risk factors to arterial thrombosis?
Age Smoking Sedentary lifestyle Hypertension DM Obesity Hypercholesterolaemia
What are the management options for arterial thrombosis?
Primary prevention: lifestyle modification and treatment of vascular risk factors
Acute presentation: thrombolysis, antiplatelet/anticoagulant drugs
Secondary prevention
What is venous thrombosis made up from?
Fibrin and red cells
What does venous thrombus result in?
Back pressure
Principally due to stasis and hyper coagulability
What are the main examples of VTE?
Limb DVT
PE
What are risk factors for venous thrombosis?
Increasing age Pregnancy Hormonal therapy: COCP/HRT Tissue trauma Immobility Surgery Obesity Systemic disease FHx
What systemic diseases can cause venous thrombosis?
Cancer
Myeloproliferative neoplasm (MPNs)
Autoimmune disease: IBD, connective tissue disease (SLE), antiphospholipid syndrome
How do you diagnose venous thrombosis?
Pretest probablility scores: Wells score/Geneve score
Lab testing if pretest probability low: D-dimer
Imaging
What are the pretest probability scores for venous thrombosis?
Wells score
Geneva score
What imaging techniques can you use to diagnosis venous thrombosis?
Doppler US
Ventilation/perfusion scan
CT pulmonary angiogram
What is the aim of management in thrombosis?
Prevent clot extension
Prevent clot embolisation
Prevent clot recurrence in long term treatment
What drugs can be used in thrombosis?
Anticoagulants: LMWH, coumarins (warfarin), DOACs
When is thrombolysis used?
Selected cases e.g. massive PE
What is heritable thrombophilia?
An inherited predisposition to venous thrombosis
What are common heritable thrombophilias?
Factor V Leiden
Prothrombin G20210A
What are rare heritable thrombophilias?
Antithrombin deficiency
Protein C deficiency
Protein S deficiency
Who is screen for thrombophilia?
High risk heritable thrombophilia (antithrombin deficiency)
What causes microvascular thrombus?
Platelets and/or fibrin
What does microvascular thrombus result in?
Diffuse ischaemia
When does microvascular thrombus usually happen?
In Disseminated Intravascular Coagulation (DIC)?
What is DIC?
Diffuse systemic coagulation activation
Consumption of platelets and clotting factors leading to bleeding
When does DIC occur?
Septicaemia
Malignancy
Eclampsia
What does DIC cause?
Tissue ischaemia: gangrene, organ failure
