Thrombosis

Question 1

What is normal blood circulation like?

Answer 1

• Tightly regulated process:
• Maintain blood in a fluid, clot-free state in normal vessels
• Allows rapid formation of HAEMOSTATIC CLOT at local site of vascular injury

Question 2

What are the three components involved in haemostasis?

Answer 2

• Vascular wall
• Platelets
• The coagulation cascade

Question 3

How is Thrombosis different from haemostasis?

Answer 3

• Pathological
• Opposites

Question 4

What is Thrombosis?

Answer 4

• A SOLID MASS of blood constituents formed within the vascular system in life due to inappropriate activation of haemostatic processes
• Poorly attached to the vessel wall and prone to fragmentation

Question 5

What are the three predisposing factors of Pathogenesis of thrombosis?

Answer 5

1) Endothelial injury
2) Stasis (slow) or turbulence (violent) of blood flow
3) Blood hypercoagulability

Question 6

Explain what Endothelial injury causes as a predisposing factor

Answer 6

• Exposure of underneath ECM
• Adhesion of platelet
• Release of tissue factor

Question 7

Explain Stasis or turbulence of blood flow as a predisposing factor

Answer 7

• Turbulence (violent) contributes to arterial and cardiac thrombosis. It can damage the endothelium
• Stasis (slow) contributes to venous thrombosis. creates a Build up due to slow pressure

Question 8

Explain Blood hypercoagulability as a predisposing factor

Answer 8

• Also called thrombophilia
• Increased tendency of blood to thrombose

Question 9

What are the risk factors for thrombosis? Explain how

Answer 9

• Prolonged bed rest or immobilization (Stasis)
• Myocardial infarction (Stasis)
• Atrial fibrillation, reduces blood flow (stasis)
• Prosthetic cardiac valves (Endothelial layer)
• Tissue injury, surgery, fracture, burn. (tissue damage causes exposure of underneath collagen
• Cancer (Tissue damage)
• Increased age (Less active, slow blood flow)

Question 10

Explain Arterial thrombosis

Answer 10

• Usually begin at sites of turbulence or endothelial injury
• Most commonly superimposed on atherosclerosis
• Frequently occlusive(blocked off)

Question 11

Where are the common sites of Arterial thrombosis

Answer 11

• Coronary, cerebral and femoral arteries

Question 12

What is Venous thrombosis

Answer 12

-Mostly occurs in superficial or deep veins of
the leg
- cause a pulmonary infarction
- most commonly due to stasis
- Can be rapidly offset by collateral bypass channels (~50% asymptomatic)
- Can cause local pain and oedema

Question 13

Where does Venous thrombosis mostly occur

Answer 13

• Most occur in superficial or deep veins of the leg

Question 14

Where does most venous thrombi begin?

Answer 14

• At valves (turbulence)

Question 15

Why does thrombosis occur in the legs more than the arms?

Answer 15

• Gravity

Question 16

What is the 4 fates of thrombus?

Answer 16

• Propagation
• Embolization
• Dissolution
• Organisation and recanalization

Question 17

What does Propagation mean? (fate of thrombus)

Answer 17

• growing bigger

Question 18

What does Embolization mean? (fate of thrombus)

Answer 18

• Dislodging and travelling to other sites in the vasculature

Question 19

What does Dissolution mean? (fate of thrombus)

Answer 19

• The result of fibrinolysis

Question 20

What does Organisation and recanalization mean? (fate of thrombus)

Answer 20

• for older thrombus

Question 21

What are the clinical complications of Arterial thrombosis?

Answer 21

• Tissue infarction distally

Question 22

What are the clinical complications of Venous thrombosis?

Answer 22

• Congestion and oedema due to impaired drainage
• Embolism

Question 23

What are the consequences of thrombosis?

Answer 23

• Lysis and resolution: Dissolved and cleared away completely
• Organisation: Organised into a scar by the invasion of macrophages
• Recanalization: reopen
• Embolism: Infraction