Thrombotic Disorders Flashcards
What does plasmin do?
Convert fibrin to fibrinogen/fibrin degradation products
What is a thrombus?
Clot in the wrong place
What is a thromboembolism?
Movement of a clot along a vessel
What is Virchow’s triad?
Thrombosis
- stasis
- hypercoagulability
- vessel damage
What causes stasis?
Bed rest
Travel
What causes hypercoagulability?
Pregnancy
Trauma
What causes vessel damage?
atherosclerosis
Describe arterial thrombosis
White clot; platelets and fibrin
Results in ischaemia and infarction
Principally secondary to atherosclerosis
What are some examples of arterial thromboembolism?
Coronary; MI, unstable angina
Cerebrovascular; stroke, TIA
peripheral; limb ischaemia
What are risk factors for arterial thrombosis?
Age Smoking Sedentary lifestyle Hypertension DM Obesity Hypercholesterolaemia
How is arterial thrombosis managed?
Primary prevention
- lifestyle modification
- treatment of vascular risk factors
Acute presentation
- thrombolysis
- antiplatelet/anticoagulant drugs
Secondary prevention
Describe a venous thrombus
Red thrombus; fibdin and red cells
Results in back pressure
Principally due to stasis and hypercoagulability
What are some types of venous thromboebolism?
Limb DVT Pulmonary embolism Visceral Venous thrombosis Intracranial venous thrombosis Superficial thrombophlebitis
What are risk factors for venous thrombosis?
Increasing age Pregnancy Hormonal therapy; COCP/HRT Tssue trauma Immobility Surgery Obesity Systemic disease FHx
How is venous thrombosis diagnosed?
Prestest probability; Wells score, Geneva Score
lab testing; D-dimer
Imaging
Describe doppler US
Compression ultrasonography
Contrast venography, CT venography, MRA
DVT: thrombosed vein enlarged, non-compressive, echogenic material may be seen
What is the aim of management in venous thrombosis?
Prevent clot extension
Prevent clot embolisation
Prevent clot recurrence long term
What drugs are used in venous thrombosis?
Anticoags;
- LMWH
- Coumarins (warfarin)
- DOACs
Thrombolysis only in selected cases; massive PE
What is heritable thrombophilia and some types?
Inherited predisposition to venous thrombosis
Types;
- Factor V leiden and prothrombin common
- antithrombin deficiency, protein C/S deficiency rare
What thrombophilia is screened for?
Limited to high risk heritable thrombophilia (antithrombin deficiency)
Screening asymptomatic family members not recommended
Describe microvascular thrombus
Platelets and/or fibrin
Results in diffuse ischaemia
Principally in disseminated intravascular coagulation (DIC)
Describe DIC
Disseminated intravascular coagulation
Occurs in; septicaemia, malignancy, eclampsia
Causes tissue ischaemia; gangrene, organ failure
Consumption of platelets and clotting factors lead to bleeding
How is compartment syndrome treated?
If there is occlusive dressing;
- First line - remove dressing and analgesia (morphine usually)
- second line - fasciotomy if removal of dressing does not relieve pressures
If no occlusive dressing
- Fasciotomy
Amputation may be necessary if fasciotomy is ineffective
What are complications of compartment syndrome?
Rhabdomyolysis
Describe compartment syndrome
Increased interstitial pressure in closed osteofascial surface which inhibits blood supply
