9. Thrombosis And Embolism Flashcards
(22 cards)
What is a thrombosis?
Formation of solid mass of blood within the circulatory system
Solid mass is the called a thrombus
What is a clot?
Mass of blood outside vessel wall
What is Virchow’s triad?
Explanation of how thrombus forms
Occurs when there is an abnormality in vessel wall, blood flow or blood components
What can the vessel wall/endothelial wall damage involve?
Atheroma
Direct injury
Inflammation
What are the possible problems with blood flow?
Stasis (slowing of blood)
Turbulent blood flow (can be caused by valves)
What possible problems with blood components are there and who is more at risk?
Hypercoagulable states (sticky blood) Smokers Pregnancy and postpartum Post operative patients Cancer patients Trauma and burns
What are the differences between arterial and venous thrombi?
Arterial: pale, granular, lines of Zahn, lower cell content
Venous : soft, gelatinous, deep red, higher cell content
What are the outcomes and complications of clotting?
Lysis Propagate Organise Recanalise Embolise
What is lysis?
Most likely when thrombi are small
Complete dissolution of thrombus
Fibrinolytic system active
Blood flow re-established
What is propagation?
Progressive spread of thrombosis
Distally in arteries
Proximally in veins
What is organisation?
Reparative process
In growth of fibroblasts and capillaries
Lumen remains obstructed
What is recanalisation?
Blood flow re-established but usually incompletely
One or more channels formed through organising thrombus
What is embolism?
Part of thrombus breaks off
Travels through bloodstream
Lodges at distant site
What are the effects of venous thrombosis on the tissue?
Congestion
Oedema
Ischaemia
Infarction
What are the effects of arterial thrombosis on the tissue?
Ischaemia
Infarction
Depends on site and collateral circulation
Where can arterial thrombosis occur?
Cerebral Carotid Coronary Mesenteric Renal Femoral/iliac/popliteal
What is an embolism?
Blockage of blood vessel by solid, liquid or gas at a site distant from its origin
Most are thrombo-emboli
What are the predisposing factors for a DVT?
Immobility/bed rest Post-operative Pregnancy and postpartum Oral contraceptives Severe burns Cardiac failure Disseminated cancer
What are the complications of a pulmonary thromboembolism?
Massive PE - >60% recursion in blood flow is rapidly fatal (especially saddle emboli)
Major PE - medium sized vessels blocked., patients short of breath, cough and blood stained sputum
Minor PE - small peripheral pulmonary arteries blocked, asymptomatic or minor shortness of breath
Recurrent minor PEs lead to pulmonary hypertension
What are the other types of embolism?
Air Amniotic fluid Nitrogen Medical equipment Tumour cells Fat, bone marrow
How can you prevent DVT/PE?
Identify high risk patients
LMW heparin sub-cutaneously
Mobilise early
Leg compressions during surgery
What are the treatments for thrombus/thromboemboli?
Clot busters IV heparin type drugs Newer generation NOAC (novel oral anticoagulants) Filters in IVC Embolectomy (e.g. in legs) Oral warfarin
