Atheroma, Thrombosis and Embolism Flashcards
Define atherosclerosis
Degradation of arterial walls characterised by fibrosis, lipid deposition and inflammation which limits blood circulation and predisposes to thrombosis
Which vessels are commonly affected by atherosclerosis?
bifurcations, abdomincal aorta, coronary arteries, popliteal arteries, carotid vessels, circles of willis
What are some non-modifiable risk factors for atherosclerosis? (4)
age, gender, family history, genetics
What are some modifiable risk factors for atherosclerosis? (4)
hyperlipidaemia, hypertension, smoking, diabetes
What is the first step in atherosclerosis?
endotherlial injury
What can cause endothelial injury?
haemodynamic injury, chemicals, immune complex deposition, irradtiation
Where do lipids accumulate in atherosclerosis formation?
intima (inner most part of vessel)
What causes the lipids in the intima to become foam cells?
monocytes which migrate into the intima
What is the sequelae of atherosclerosis?
occlusion, weakening of vessel walls (aneurysm formation), erosion
Define thrombosis
solidification of blood contents formed in the vessel during life
Give 4 characteristics of clots that differentiate them from thrombus
form in stagnant blood, enzymatic process, elastic, adopts shape of vessel
What are platelets?
fragments of megakaryocytes in the bone marrow
What do platelets secrete?
alpha granule and dense granules
What are the factors of Virchow’s triad?
intimal surface of vessel, pattern of blood flow, blood constituents
What is the intimal change in venous thrombosis?
valves
What is the name for thrombi in the heart?
mural thrombi
What is the sequelae of thrombosis?
occlusion of vessel resolution incorporation into vessel wall recanalisation embolisation
Define embolus
a mass of material in teh vascular system able to lodge in a vessel and block it
What is the most common for of embolism?
pulmonary embolism
Where do systemic emboli arise?
the heart (MI or AF), arterial circulation (atheroma)
What normally causes infective emboli?
vegetation on infected heart valves
How big must a gas embolism be to cause clinical effects?
> 100ml
Who is at risk of decompression sickness?
divers and tunnel workers
Can nitrogen bubbles enter bones, joints and lungs?
yes
