Atherosclerosis : Pathophysiology of Thrombosis + Embolism Flashcards
<p>What is normal flow of blood?</p>
<p>Laminar</p>
<p>What is meant by stasis?</p>
<p>Stagnation of flow</p>
<p>What is meant by turbulence?</p>
<p>Forceful unpredictable flow</p>
<p>What are the causes of common defects in blood flow?</p>
<p>Thromboembolism</p>
<p>Atheroma</p>
<p>Hyperviscosity</p>
<p>Spasm</p>
<p>External compression</p>
<p>Vasculitis vascular steal</p>
<p>What is meant by Virchow's triad?</p>
<p>•Changes in the blood vessel wall</p>
<p>•Changes in the blood constituents</p>
<p>•Changes in the pattern of blood flow</p>
<p>What does Virchow's triad influence?</p>
<p>They are the factors causing thrombosis</p>
<p>Give an example of a change in the vessel wall</p>
<p>Atheromatous coronary artery</p>
<p>What is the basic pathogenesis of thrombosis?</p>
<p>Endothelial injury</p>
<p>Stasis or turbulent blood flow</p>
<p>Hypercoagulability of the blood</p>
<p>What are lines of Zahn on a thrombus?</p>
<p>Represent bands of fibrin (lighter) with entrapped white blood cells and red blood cells (darker).</p>
<p>What causes the adherence of platelets?</p>
<p>Loss of intimal cells and the exposure of collagen</p>
<p>What traps red blood cells in a blood clot?</p>
<p>Fibrin meshwork</p>
<p>What is responsible for the propagation of thrombosis?</p>
<p>Further turbulence and platelet deposition</p>
<p>What is the relationship between atheroma and thrombosis?</p>
<p>Arterial thrombosis most commonly superimposed on atheroma; Virchow’s triad</p>
<p>What are the possible changes in the blood constituents (Virchow’s triad) that can result in thrombosis?</p>
<p>Hyperviscosity, post - operative traumatic hypercoagulability</p>
<p></p>
<p>Hypercholesterolaemia?</p>
<p>What are the possible alterations in blood flow (Virchow’s triad) that can result in thrombosis?</p>
<p>Stasis - post op "economy class syndrome"</p>
<p>Turbulence: atheromatous plaque, aortic aneurysm</p>
<p></p>
<p>What do the consequences of thrombosis depend on?</p>
<p>Site, extent and colalteral circulation</p>
<p>What are the resolutions of thrombosis?</p>
<p>Resolution</p>
<p>Organisation/recanalisation</p>
<p>Death</p>
<p>Propagation - embolism</p>
<p>What is embolism defined as?</p>
<p>Movement of abnormal material in the bloodstream and its impact in a vessel, blocking its lumen</p>
<p>What is an embolus?</p>
<p>Detatched intravascular solid, liquid or gaseous mass</p>
<p>What is a thromboembolism?</p>
<p>Embolus resulting from dislodged thrombus</p>
<p>What is a systemic/arterial thromboembolus?</p>
<p>Mural thrombus</p>
<p>Aortic aneurysms</p>
<p>atheromatous plaques</p>
<p>Valvar vegetations</p>
<p>Venous thrombi - paradoxical emboli</p>
<p>What are mural thrombi associated with?</p>
<p>Myocardial infarction or left atrial dilation and atrial fibrilation</p>
<p>Where can a systemic thrombus travel to?</p>
<p>Wide variety of sites: lower limbs most common, brain and other organs.</p>
<p>What is the usual result of a systemic thromboembolus?</p>
<p>Usually infarction.</p>
<p>Consequences depend on vulnerability of affected tissues to ischaemia, calibre of occluded vessel, collateral circulation</p>
<p>What is a venous thromboembolus?</p>
<p>Originate from deep venous thromboses (lower limbs)</p>
<p>Most common form of thromboembolic disease</p>
<p>Where do venous thromboembolus usually travel amd occlude?</p>
<p>Travel to the pulmonary arterial circulation, may occlude the main pulmonary artery, bifurcation or smaller arteries</p>
<p>What are the possible consequences of thromboembolism?</p>
<p>Depend on size of embolus: silent, pulmonary haemorrhage/infarction, right heart failure, sudden death</p>
<p>Multiple PE over time: pulmonary hypertension and right ventricular failure</p>
<p>What are risk factors for deep vein thrombosis and pulmonary embolism?</p>
<p>Cardiac failure</p>
<p>Severe trauma</p>
<p>Burns</p>
<p>Post op</p>
<p>Post partum (following childbirth)</p>
<p>Nephrotic syndrome</p>
<p>disseminated malignancy</p>
<p>Oral contraceptive</p>
<p>Increased age</p>
<p>Obesity</p>
<p>Bed rest/immobilisation</p>
<p>Obesity,</p>
<p>Past medical history of deep vein thrombosis</p>
<p>What is prophylaxis for deep vein thrombosis?</p>
<p>TEDS - long, tight fitting stockings that place mild static pressure on the legs to prevent blood from clotting</p>
<p>Heparin - a compound occurring in the liver and other tissues which inhibits blood coagulation.</p>
<p>When might you suffer from a fat embolism?</p>
<p>After a fracture</p>
<p>Syndrome of fat embolism: brain, kidneys, skin affected</p>
<p>What is gas embolus?</p>
<p>Decrompression sickness</p>
<p>•N2 forms as bubbles which lodge in capillaries</p>
<p>Apart from diving when can you get an air embolism?</p>
<p>Surgery -Small amounts of air often get into the blood circulation accidentally during surgery and other medical procedures (for example a bubble entering an intravenous fluid line), but most of these air emboli enter the veins and are stopped at the lungs, and thus a venous air embolism that shows anysymptomsis very rare</p>
<p>Apart from systemic thrombus, DVT, Fat and gas what are the other types of embolus?</p>
<p>Tumour</p>
<p>Trophoblast -a layer of tissue on the outside of a mammalian blastula, supplying the embryo with nourishment and later forming the major part of the placenta.</p>
<p>Septic material (e.g infective endocarditis)</p>
<p>Amniotic fluid (cause of collapse)</p>
<p>Bone marrow (fractures)</p>
<p>Foreign bodies (Intravascular cannulae tips, sutures)</p>
