Thrombosis

Question 1

define thrombus.

Answer 1

• solid mass formed within circulatory system

- whereas a clot is a mass of blood outside the vessel wall in damaged vasculature.

Question 2

how is a thrombus formed?

Answer 2

• virchow’s triad : abnormality in vessel wall, blood flow or blood components.

Question 3

stasis and turbulent blood flow are 2 problems with blood flow. define them.

Answer 3

• stasis is the slowing of blood due to narrowing, immobility or low blood pressure.
• turbulent flow disrupted flow due to defects in wall and heart valves, T-Fib or area of dead cardiac muscle.

Question 4

what could cause a hypercoaguable state of blood?

Answer 4

• smoking.
• pregnancy.
• post operative.
• cancer.
• Covid-19.
• genetic : anti-thrombin iii deficiency.

Question 5

differentiate between arterial and venous thrombi.

Answer 5

• arterial are pale, granular, low cell content whereas venous thrombi are soft, gelatinous, deep red with high cell content.

Question 6

name some outcomes or complications of thrombosis.

Answer 6

• lysis : breakdown of thrombus usually when small resulting in complete dissolution and blood flow back.
• propagate : spread of thrombosis, distally in arteries, proximally in veins.
• organise : reparative, ingrowth of fibroblasts and capillaries, lumen obstructed.
• recanalise : channels through thrombus to re-establish blood flow incompletely.
• embolise : part of thrombus breaks and travels through blood stream and lodges at distant site.

Question 7

what are some effects of venous thrombosis on tissue.

Answer 7

• congestion.
• oedema.
• ischaemia.
• infarction.

Question 8

what are some effects of arterial thrombosis on tissue.

Answer 8

• ischaemia.
• infarction.
• depends on collateral circulation.

Question 9

define an embolism.

Answer 9

blockage of blood vessel by solid, liquid or gas at a distant site from origin. mostly thrombo-emboli.

Question 10

name some common sites of thrombosis.

name a further complication of each.

Answer 10

• veins : DVT often leads to pulmonary embolism.
• heart : MI, fragments into aorta and lodged in cerebral arteries leading to ischaemic stroke.
• carotid artery : atherosclerotic plaque may lead to emboli and ischaemic strokes.
• abdominal aorta : plaque or aneurysm with thrombus developing to emboli leading to acute limb ischaemia.

Question 11

define DVT and name some predisposing factors.

Answer 11

• deep vein thrombosis : blood clot in a vein. If embolised may lead to pulmonary embolism.
• immobility, post-operative, pregnancy, cardiac failure.

Question 12

what are some complications of pulmonary thrombo-emboli?

Answer 12

• if found in main pulmonary artery sudden death.
• small embolus in peripheral pulmonary artery pulmonary infarct.
• multiple repeated emboli cause pulmonary hypertension.

Question 13

do you know of any other types of emboli?

Answer 13

• air, amniotic fluid, tumour cells, fat and bone marrow post trauma.
• air bubble secondary to pulling out of cannulation.
• fat emboli usually secondary to trauma.

Question 14

how would you prevent thrombosis and thromboembolism?

Answer 14

• identify high risk patients.
• heparin sub-cutaneously.
• aspirin.
• leg compression stockings or flow-tron boots.

Question 15

what features would lead for you to suspect DVT?

Answer 15

• well’ score of 2 or more : immobility, local tenderness, swelling, previous DVT etc.
• D-dimers in blood.
• anticoagulant therapy.

Question 16

how would you treat DVT?

Answer 16

• clot busters and thrombo-lysis if stable.
• CT or USS for DVT.
• oral warfarin.
• heparin.
• devices in left atria to stop thrombus forming.
• embolectomy.