Thrombosis

Question 1

What is normal blood flow called?

Answer 1

laminar

Question 2

What are the two abnormal blood flow types called?

Answer 2

stagnant

turbulent

Question 3

What factors affect blood flow?

Answer 3

viscosity and velocity of blood
diameter of vessel (compliance)
pressure gradient
resistance

Question 4

Name some ways that blood flow can become compromised.

Answer 4

thromboembolism

atheroma 
hyperviscosity (dehydration)
spasm 
external compression (tumour) 
vasculitis 
vascular steal (blood flow is stolen form one area to supply another)

Question 5

What is Virchows Triad ?

Answer 5

factors causing thrombosis

Question 6

Nam the three Virchowds triad.

Answer 6

change in:

• blood vessel wall
• blood constituents
• blood flow pattern

Question 7

What is a thrombosis ?

Answer 7

Formation of a solid mass from the constituents of blood within the vascular system during life

Question 8

What is a clot?

Answer 8

Clot – blood solidifies outside the vessels

Question 9

Pathogenesis of a thrombosis

Answer 9

• Injury to the endothelium
• Atheromatous coronary artery
• Turbulent blood flow (fibrin deposition, platelet clumping)
• Loss of intimal cells (endothelium), denuded plaque
• Collagen exposed, platelets adhere
• Fibrin meshwork, RBCs trapped
• Appearance of alternating bands: lines of Zahn
• Further turbulence and platelet deposition
• Propagation – becomes bigger
• Clinical Consequences

Question 10

What is the most important factor of the formation of an atheroma?

Answer 10

Hypercholesterolaemia

Question 11

The damage and consequences of an atheroma and thrombosis depends on..??

Answer 11

Site (where abouts in the body)
Extent (% covering lumen)
Collateral circulation (can the thrombosis be by passed?)

Question 12

What are the four outcomes of a thrombosis?

Answer 12

Resolution
Organization/ recanalization
- tissue damage as this takes a couple of weeks
- endothelium grow over and inflammatory cells invade to produce scar tissue and recanalises so there are smaller lumen within the thrombosis.
Death
Propagation
- embolism

Question 13

What are the ten types of embolise?

Answer 13

Systematic/arterial thromboembolism - Paradoxical emboli, Mural thrombus

Venous Thromboembolism - originate from DVT

Gas - depression sickness, scuba divers, miners

Amniotic

Air

Tumour

Septic material - infective endocarditis

Bone marrow - CPR, fractures

Foreign material

Trophoblast - common in pregnant women