MOD 13 - Atherosclerosis and embolism Flashcards Preview

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Flashcards in MOD 13 - Atherosclerosis and embolism Deck (25):

definition of atherosclerosis

degeneration of arterial walls characterised by fibrosis, lipid deposition and inflammation which limit blood circulation and predisposes to thrombosis


what are the commonly affected arteries

bifurcations (sites of turbulent flow), abdominal aorta, coronary arteries, popliteal arteries, carotid vessels, circle of willis


risk factor for atherosclerosis

age, male, FH, genetics, hyperlipidaemia (LDL:HDL), hypertension, smoking, diabetes, CRP, stress


what is the first step in the road to atherosclerosis

endothelial injury (arises due to chronic injury and repair of the endothelium) - haemodyanmic injury , chemicals, immune complex deposition, irradiation


how is atheroma formed

- endothelial injury

- hyperlipidaemia (lipid deposit in intima by the recognition of scavenger receptors which recognise LDL)

- monocytes migrate into intima (lipid and endothelial injury) to ingest lipid forming 'foam cell' - fatty streak

- foam secrete chemokines

- attract more monocytes, lymphocyes & smooth muscle cells

- smooth muscle cells proliferate and secrete connective tissue

- mixture of fat, extracellular material and luekocytes and smooth muscle form the atherosclerotic plaque


what is the constituent of atherosclerotic plaque

fat, extracellular material, leukocytes, smooth muscle


what is atheromatous plaque

progression of atherosclerotic plaque

fibrous cap (smooth muscle cells, macrophages, foam cells, lymphocytes, collagen etc), necrotic center, media


what is the structure of the atheromatous plaque

shoulder, cap, core


what will happen to the atherosclerosis

grow larger, occlusion of the arteries, weakening of vessel walls (aneurysm formation), erosion (thrombosis)


what is thrombosis

solidification of blood content formed in the vessel during life


what are the difference between thrombosis and a clot

thrombus - within the body during life, dependent on platelets, firm

clot - stagnant blood, enzymatic process, elastic, adopts shape of vessels


what does the platelet adhesion and subsequent thrombous require according to virchow's triad

intimal surface of the vessel, pattern of blood flow, blood constituents


how does arterial thrombus form

normal - atheroma (change in flow) - ulceration (loss of endothelial cells) - platelet adherence to the ulcerative site - thrombus formation


what can cause cardiac thrombosis

arrhythmias and cardiomyopathy


what is the sequelae of thrombosis

occlusion of vessel, resolution, incorporation into vessel wall, recanalisation, embolisation


what is embolus

a mass of material in vascular system able to lodge in a vessel and block it - can be endo or exogenous, maybe solid, liquid or gas


what is the most common embolism

pulmonary emboli


risk factor for venous thromboembolism

immobility, malignancy, previous VTE, heart failure, oestrogens, obesity, pregnancy, renal disease, smokers, thrombotic disorder (FV leiden)


what are some of the effect of venous thromboembolism

small - asymptomatic (if multiple can result in pulmonary hypertension)

medium - cause acute respiratory and cardiac failure

large - death - saddle emboli


what is the common cause of infective embolism

usually from vegetations on infected heart valves - can lead to aneurysm formation


what is tumour embolism

bits breaks of as tumours penetrate vessels


what can cause gas embolism

air - vessel opened into the air

nitrogen - decompression sickness eg divers, tunnel workers


what is amniotic fluid embolism

Increased uterine pressure during labour may force AF into maternal uterine veins


what is fat embolism

microscopic fat embolism found in 80% of patients


what is foreign body embolism

particles injected intravenously