Thrombosis & Embolism Flashcards
Difference between Thrombosis and Clot
Thrombosis: Formation of a solid mass within the circulatory system
Clot: Mass of blood outside the vessel wall
How is a thrombus formed
Occurs when there is an abnormality in
(Virchows’ trad)
1. Vessel wall (endothelial damage)
2. Blood flow (slow/turbulent flow)
4. Blood components (hyper-coagulability)
List factors damaging wall of the vascular system
Atheroma
Inflammation
Direct injury
Damage to heart
Different types of embolism
Thromboembolism (>90%)
Air
Amniotic fluid
Nitrogen
Tumour cells(disseminated malignancy)
Fat, Bone marrow (post trauma)
Outcomes/Complications of thrombosis
Lysis
Propagate
Organise
Recanalise
Embolise
Structure of arterial and venous thrombus
Arterial: Pale, Granular, Lower cell content, Lines of Zahn (RBC)
Venous: Soft, Gelatinous, Deep red, Higher cell content
What is lysis in thrombosis
Complete dissolution of thrombus
Fibrinolytic system active
Blood flow re-established
What is propagation in thrombosis
Progressive spread of thrombosis
-distally in arteries
-proximally in veins
What happens during organisation in thrombosis
Reparative process
-ingrowth of fibroblasts & capillaries
-lumen remains obstructed
What happens in recanalisation in thrombosis
One or more channels form through area of organising thrombus
-blood flow can be re-established but usually incompletely
What is Embolism
Blockage of a BV by solid, liquid or gas at a site distant from its origin
Effects of venous and arterial thrombosis on the tissue
Venous: congestion, oedema, ischaemia, infarction
Arterial: ischaemia, infarction
Where can Thrombosis arise in
Veins (DVT→Pulmonary embolism)
Heart (Endocardial thrombus, vegetations, atrial fibrillation→Ischaemic stroke, renal/limb infarcts)
Carotid Artery: Atherosclerotic plaque with development of thrombus→Emboli→Cerebral Ischaemia
Abdominal aorta: Atherosclerotic plaque/aneurysm with thrombus→emboli→Acute limb ischaemia
Predisposing factors of DVT
Immobility
Post-operative
Pregnancy, post-partum
Oral contraceptives
Severe burns
Cardiac failure
DIsseminated cancer
Superficial thrombophlebitis
Prevention of thrombosis & thromboembolism
-LMW heparin subcutaneously
-Mobilise early
-+/- Aspirin
-Leg compressions during surgery
(TED stockings, Flowtron boots)
