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54 Cards in this Set
- Front
- Back
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What is an atheroma? |
Plaques found particularly in elastic and medium to large muscular arteries |
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What is athersclerosis? |
Porridge like hardness, consequence of atheroma |
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What is arteriosclerosis |
Hardening of arteries One cause is atheroma |
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Name two less common causes of arteriosclerosis |
Age-related sclerosis Calcification |
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Risk factors for Atheroma |
Age Male sex Genetics Hyperlipidaemia Hypertension Smoking Diabetes mellitus |
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Pathogenesis for atheroma |
Chronic endothelial injury/dysfunction --> accumulation of intimal lipid and foamy macrophages --> smooth muscle proliferation --> fibrosis forming a fibro-lipid plaque -->plaque injury - thrombosis and haemorrhage |
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Where do atheromas occur? |
Elastic and medium-to-large muscular arteries: Abdominal aorta Coronary arteries Popliteal arteries Descending thoracic aorta Internal carotid arteries Vessels of circle of Willis (base of brain) |
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Complications of atheroma |
Calcification Ulceration Plaque rupture Haemorrhage Thrombosis Aneurysmal dilatation |
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What do most complications of atheroma lead to? |
Vessel obstruction and downstream ischaemia |
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What can particularly occur with abdominal aortic aneurysms? |
external vessel rupture |
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What is a thrombus |
A solidification of blood constituents that forms w/n vascular system during life |
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What is thrombosis? |
Denotes pathological process of the formation of a thrombus within an uninterupted vascular system |
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What is a blood clot/haemotoma |
Blood clot is a solidifcation of blood constituents outside the vascular system or after death |
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Risk factors for thrombosis? |
Endothelial Injury Hypercoagubility Abnormal Blood Flow |
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Where do ulcerated atheromatous plaques commonly occur? |
Aorta Carotid arteries Iliac and femoral arteries Coronary arteries due to endothelial injury |
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What kind of endothelial injury can occur after MI? |
Left ventricular endocardium |
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How can you get abnormal cardiac valves which lead to endothelial injury |
Rheumatic fever Infective endocarditis Prosthetic valves |
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What does abnormal blood flow do? |
Disrupts laminar flow Prevents dilution of clotting factors Retards inflow of inhibitors of clotting factors Promotes endothelial cell activation |
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What is turbulence |
Abnormal blood flow that contributes to development of arterial and cardiac thrombi |
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What is stasis? |
Abnormal blood flow Important in the formation of venous thrombi |
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What is hypercoagulability and how can it occur? |
It's the alteration of blood coagulation mechanism (particularly platelets and clotting cascade) that in some way predisposes to thrombosis May be genetic predisposition eg protein S or protein C deficiency May be acquired eg after surgical procedures |
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Describe a mural thrombi |
Applied to one wall of underlying structure |
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Where do mural thrombi occur? |
Occur in capaciuous cavities of cardiac chambers and the aorta |
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Are arterial thrombi usually occlusive? |
Yes, sometimes mural though |
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Where are arterial thrombi frequent |
Coronary Carotid Cerebral Femoral arteries |
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What's another term for venous thrombosis? |
Phlebothrombosis |
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Where do venous thrombosis usually occur |
Typically in pelvic and leg veins in association with stasis |
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Describe the histological appearance of thrombi |
Alternating pale and dark "lines of Zahn" pale band of fibrin and platelets dark (red) band of red blood cells |
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Complications of Thrombosis |
Occlusion of artery or vein Embolism - arterial and venous Arterial occlusion |
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What is arterial occlusion |
Loss of pulse distal to thrombus Area becomes cold, pale, painfull Eventually tissue dies and gangrene results |
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What are two types of venous thrombosis? |
Superficial - saphenous system - congestion,, swelling, pain, tenderness (rarely embolise) Deep - foot and ankle oedema - may be asymptomatic and recognised only when they have embolised to the lung |
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What are the four outcomes for venous thrombosis? |
Resolution Embolisation to lungs Organised and recanalised --> organised and incorportaed into wall |
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What is an embolus? |
A detached intravascular solid, liquid or gaseous mass that is carried by the blood to a site distant from its point of origin 99% of all emboli arise from thrombi (thromboembolism) Unless otherwise qualified, the term embolus implies thromboembolism |
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Less common / rare forms of emboli include fragments of: |
Bone or bone marrow Atheromatous debris Droplets of fat Tumour cellls Foreign bodies (such as bullets) Bubbles of air or nitrogen |
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Name five types of embolism |
Pulmonary embolism Systemic embolism Amniotic fluid embolism Air embolism Fat embolism |
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Pulmonary embolism |
Embolism usually thromboembolism to the pulmonary arteries Occlusion of a large or medium sized pulmonary artery in embolic in origin until proved otherwise |
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Where do most pulmonary emboli form? |
Large deep veins of lower leg |
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What is next most common origin of pulmonary emboli after large deep veins of lower leg? |
Pelvic veins, in association with pelvic masses |
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What is a saddle embolus? |
Large emboli that impacts in the main pulmonary artery or lodge at the bifurcation |
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What are saddle emboli associated with |
Collapse and sudden death Their effect is to cause circulatory obstruction |
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What is a paradoxical embolism? |
When an emboli gains access to the systemic circulation in the presence of an interatrial or interventricular defect |
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Pulmonary embolism and infarction |
Pulmonary infarction is typically haemorrhagic base of infarct faces pleural surface patients present with haemoptysis or pleuritic chest pain |
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What are systemic embolism |
Emboli that travel through the systemic arterial circulation NB 80-85% arise from thrombi within the heart |
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Name some less common sources for systemic emboli |
Ulcerated atherosclerotic plaques Aortic aneurysms Infective endocarditis Artificial heart valves and aortic grafts |
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What kind of emboli almost always cause infarction |
Arterial emboli |
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Name some major sites for systemic emboli to lodge? |
Lower extremities (commonest) The brain Viscera (mesenteric, renal, splenic areries) Upper limbs (much less common) |
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What is necrosis |
Refers to a spectrum of morphological changes that follow cell death in living tissue, largely resulting from progressive action of enzymes on lethally injured cells |
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What two causes account for the vast majority of infarctions? |
Thrombosis and thromboembolism |
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Name some other causes of infarction |
Vasospasm Expansion of atheroma Compression of a vessel Twisting of vessels through torsion Traumatic rupture |
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What four factors influence development of an infarct? |
Nature of vascular supply - single or double? Rate of development of occlusion - rapid occlusion more likely to cause infarction Vulnerability of affected tissue to hypoxia - more metabolically active tissues more vulnerable eg heart Oxygen content of blood - hypoxia increases risk |
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Three types of infarct? |
Red (haemorrhagic) - venous occlusion eg torsion, loose tissues and tissues with a dual circulatiion eg lung White (anaemic) - arterial occlusions and solid organs eg heart, spleen Septic = infected infarcts |
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What type of infarct is an ovarian infarct and what does it look like |
Haemorrhagic infarction Venous occlusion as a result of torsion Dark blue and haemorrhagic |
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Describe two types of "anaemic" infarct |
Splenic infarcts - wedge shaped and white Renal infarct - wedge shaped, white, rim of hyperaemia |
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Histopathology of Infarction |
Ischaemic coagulative necrosis (minutes - days) Inflammatory response (hours - 7 days) Reparative response (1-2 weeks) Scarring (2 weeks - 2 months) |
