Thrombotic disorders Flashcards
What is primary haemostasis?
Initial plug from platelets
What is thromboembolism?
Movement of thrombus through a blood vessel
What is virchow’s triad?
3 factors that lead to thrombosis:
Stasis
Hypercoagulability
Vessel damage
What can cause stasis?
Bed rest
Travel
What can cause hypercoagulability?
Pregnancy
Trauma
What can cause vessel damage?
Atherosclerosis
What are the biggest component of arterial thrombus?
Platelets over fibrin
What happens as a result of arterial thrombus?
Ischaemia and infarction typically secondary to atheroma
What is caused by coronary thrombosis?
MI
Unstable angina
What is caused by cerebrovascular thromboembolism?
Stroke
TIA
What is caused by peripheral embolism?
Limb ischaemia
What are risk factors for arterial thrombosis?
Age Smoking Sedentary lifestyle Hypertension Diabetes mellitus Obesity Hypercholesterolaemia
How is arterial thrombosus managed?
Primary prevention - lifestyle modification, treatment of vascular risk factors
Acute presentation - thrombolysis, antiplatelet/anticoagulant drugs
Secondary prevention
What is a venous thrombus composed of?
Fibrin and red cells
What are other names for atherial thrombus and venous thrombus?
White clot - arterial
Red clot - venous
What is the main cause of venous thrombus?
Stasis and hypercoagulability
What are common venous thrombosis problems?
Limb DVT Pulmonary embolism Visceral venous thrombosis Intracranial venous thrombosis Superficial thrombophlebitis/thrombosis
Why does cervical rib cause risk of upper limb DVT?
Rib presses on the subclavian vein
What are risk factors for venous thrombosis?
Increasing age Pregnancy Hormonal therapy Tissue trauma Immobility Surgery Obesity Systemic disease Family history
What systemic diseases are associated with venous disease?
Cancer Myeloproliferative neoplasm IBD Connective tissue disease ie lupus Antiphospholipid syndrome
How is venous thrombosis diagnosed?
Pretest probability scoring - Wells score, Geneva score
D-dimer is pretest probability low
Imaging
What is the aim of venous thrombosis management?
Prevent clot extension
Prevent clot embolisation
Prevent clot recurrence in long term treatment
What are the most common modalities for imaging of venous thrombosis?
Doppler ultrasonography for DVT - if vein isn’t compressible indicative of clot
V/Q scan
CXR
CT pulmonary angiogram - gold standard for PE
What drugs are used to treat venous thrombosis?
Anticoagulant - Low molecular weight heparin, coumarins (warfarin), Direct oral anticoagulants
Thrombolysis only in selected cases - massive PE
How long do you anticoagulate patients for in venous thrombosis?
Minimum of 3 months, after 3 months decide if it’s long term
Who is treated long term for venous thrombosis?
People with associated ongoing risk factors
What is heritable thrombophilia?
Inherited predisposition to venous thrombosis
What is the most common mutation causing heritable thrombophilia?
Factor V Leiden
What are components of microvascular thrombus?
Platelets and/or fibrin
What happens as a result of microvascular thrombosis?
Diffuse ischaemia
What is the commonest cause of microvascular thrombosis?
Disseminated intravascular coagulation
Where does disseminated intravascular coagulation occur?
Septicaemia
Malignancy
Eclampsia
