Thrombosis

Question 1

Haemostasis

Answer 1

Haemostasis is the balance between the flow and clotting of blood

This balance regulates normal circulation

The main components of haemostasis are the vascular wall, platelets and the coagulation cascade

Question 2

Thrombosis

Answer 2

Thrombosis describes excessive blood clotting

A thrombus is a solid mass of blood and clotting factors inside the blood vessels, it can limit circulation

Question 3

Mechanisms of thrombosis

Answer 3

1. Endothelial injury - Bursting of a blood vessel leads to exposure of collagen and release of tissue factor
   This triggers the coagulation cascade and adhesion of platelets to the site
2. Blood stasis-
   Stasis can lead to accumulation of platelets and unnecessary clotting
3. Blood turbulence -
   Turbulent blood flow can damage the endothelium
4. Blood hypercoagulability -
   Some diseases can cause clotting factors to become more active

Question 4

Arterial thrombosis

Answer 4

Commonly associated with atherosclerotic plaques

Plaques can protrude into the blood vessel and cause turbulence

Common sites = coronary, cerebral and femoral arteries

Question 5

Venous thrombosis

Answer 5

Commonly associated with blood flow stasis

Can lead to a pulmonary infarction if the thrombus moves into the lung circulation

Common sites = superficial or deep veins of the leg

Question 6

Risk factors for thrombosis

Answer 6

• Prolonged best rest
• Myocardial infarction
• Atrial fibrillation
• Prosthetic heart valves
• Tissue injury
• Cancer
• Age

Question 7

Deep vein thrombosis

Answer 7

DVT often occurs in the leg

Risk factors include sitting for long periods

This can be offset using compression stockings, exercise, aspirin and remaining hydrated

Question 8

Complications of thrombosis

Answer 8

Arterial thrombosis = can lead to tissue infarction

Venous thrombosis = can lead to congestion and oedema, as well as embolism