diseases Flashcards
1- what is thrombosis?
- formation of a solid mass from the constituents of blood within the vascular system during life
- due disruption of Virchow’s Triad (endothelial injury, statis/ turbulent blood flow, hypercoagulability of blood)
1- where do you find a clot?
outside the body’s arteries + veins (? unconfirmed)
1- what are the symptoms for thrombosis?
ischaemia (insufficient blood flow to an organ, especially heart muscle)
1- what is the cause of thrombosis?
- pathogenesis: atheromatous coronary artery, turbulent blood flow, loss of intimate cells; denuded plaque; collagen exposed (platelets adhere and become activated)
- fibrin meshwork, RBCs all trapped = alternating bands (bands of Zahn (dark/light)
- further turbulence + platelet deposition
- propagation
- consequences
1- what are the three poles of Virchow’s triade?
- changes in blood vessel wall (atheroma)
- changes in the blood constituents (hyperviscosity/ hypercoagulability due to pregnancy or trauma)
- changes in the pattern of blood flow (stasis due to bed rest or travel/ turbulent)
1- what are the possible consequences of thrombosis?
depend on site/ extent/ collateral circulation (could be DVT, ischaemic limb disease, MI)
1- what are the possible outcomes of thrombosis?
- resolution
- organisation/ recanalisation
- propagation = embolism
- death
2- what is an embolism?
movement of abnormal detached intravascular solid/ liquid/ gaseous mass in the bloodstream, blocking the lumen of a vessel
2- where do most emboli come from?
they are mostly dislodged thrombi (thromboembolism)
2- what factors cause an embolism?
depends on the type of embolism
2- what is a systemic/ arterial thromboembolus? what are it’s consequences?
travels to wide variety of sites (lower limbs most common/ brain), consequences depend on vulnerability of affected tissues to ischaemia, calibre of occluded vessel, collateral circulation but usually:
- infarction occurs (ex: mural thrombus / aortic aneurysms / atheromatous plaques / valvular vegetations
2- what is a venous thromboembolus? where can it travel? what are it’s consequences?
originate from deep venous thrombosis (lower limbs); most common form of thromboembolic disease; can travel to the pulmonary arterial circulation; depending on size, may occlude main pulmonary artery / bifurcation / smaller arteries; often multiple; can cause silent issues / pulmonary infarction / right heart failure / sudden death
2- when can fat be an embolism? what organs can be affected?
- after major fractures
- syndrome of fat embolism in the brain/ kidneys/ skin affected
2- when can gas be an embolism?
- decompression sickness
- N2 forms as bubbles which lodge in capillaries
2- when can air be an embolism? how do you manage this?
- head and neck wounds, surgery
- cv catheters
2- when can tumours be similar to an embolism?
in metasasis
2- where can a trophoblast act as embolism?
can lodge in the lungs of pregnant women
2- when can septic material be an embolism?
in infective endocarditis
2- when can amniotic fluid be an embolism?
rare obstetric condition where amniotic fluid gets in mother’s bloodstream- common cause of collapse + death in childbirth
2- when can bone marrow be a embolism?
fractures (due to CPR)
2- when can foreign bodies form an embolism?
intravascular cannula tipis/ sutures
3- what is atherosclerosis/ atheroma
- formation of focal elevated lesions (plaques) in the intima of large and medium sized arteries
3- what can be the outcome of atherosclerosis/ atheroma?
- in coronary arteries this can lead to narrowed lumens and result in coronary ischaemia (reduced blood supply to the heart)
3- what can be the outcome of coronary ischaemia?
- angina
- myocardial infarctions (atheroma complicated by thromboembolism)
3- how is arteriosclerosis different from atherosclerosis?
arteriosclerosis is an age related change in muscular arteries (smooth muscle hypertrophy + reduplication of internal elastic laminae leads to intimal fibrosis and the vessel diameter decreases); cause of cardiac/ cerebral/ colonic/ renal ischaemia in the elderly
3- what is the pathogenesis of atherosclerosis/ atheroma?
- endothelial injury + dysfunction
- accumulation of lipoprotein (LDL) in vessel wall
- monocyte adhesion to endothelium
- migration into intima and transformation to foamy macrophages platelet adhesion
- factor release from activated platelet + macrophages -> recruits smooth muscle cells
- smooth muscle cells proliferation and produce an extracellular matrix + recruit T cells
- lipid accumulation (extracellular and in foamy macrophages) = necrotic core
- fibrous cap
3- what happens if the atherosclerosis/ atheroma ruptures?
exposure of highly thrombotic plaque contents (collagen/ lipid/ debris) to blood stream; activation of coagulation cascade and thrombotic occlusion in very short time
3- what are the signs for atherosclerosis/ atheroma?
- hyperlipidaemia
- corneal arcus (white ring around the iris)
- tendon axanthomata (swelling on the knuckles/ achilles)
- xanthelasmata; fat deposits around the eye
3- what are the complications of atherosclerosis/ atheroma?
- stenosis of 50-75% -> reversible tissue ischaemia -> angina
- very severe stenosis -> ischaemic pain at rest -> unstable agina
- peripheral lower limb stenosis -> intermittent claudication
- longstanding tissue ischaemia -> atrophy of tissue (wasting away)
- acute occlusion -> necrosis / infarction of tissues; myocardial infarction/ cerebral infection/ lower limb gangrene
- aneurysm
3- what are the risk factors for atherosclerosis/ atheroma?
- hypercholesterolaemia (most important risk factor as it causes plaque formation an d growth in absence of the others (LDL cholesterol) (comes from a mutation whereby you lack cell membrane receptors for LDL results in elevated plasma levels)
- smoking
- hypertension
- diabetes mellitus
- male
- elderly
- obesity/ sedentary lifestyle/ low birthweight/ low socio-economic status (all these are less common)
3- what causes endothelial injury?
- haemodynamic disturbances (turbulent flow)
- hypercholesterolaemia (increasing local production of reactive oxygen species which directly impairs endothelial cell function; function alters and they express cell adhesion molecules/ increase permeability for LDL and increase thrombogenicity)
3- what are the different layers of the artery wall? (from inside to outside)
endothelium, tunica intima, integral elastic lamina, tunica media, external elastic lamina, tunica adventitia/ external
3- how does the growth of atherosclerosis mainly take place in beginning? (1st & 2nd decade)
- growth mainly by lipid accumulation
- foam cells
- fatty streaks; yellow linear elevation of intimal lining (lipid-laden macrophages); may disappear/ no clinical significance
3- how does the growth of atherosclerosis take place at a later stage? (3rd decade)
- growth mainly by lipid accumulation
- intermediate lesions
- atheroma