Pathophysiology of Thrombosis

Question 1

what is stasis of blood flow?

Answer 1

stagnation of flow

Question 2

what is turbulent blood flow?

Answer 2

forceful, unpredictable flow

Question 3

name some other causes of defects in blood flow

Answer 3

> atheroma
hyperviscosity
vessel wall spasm
external compression (tumour)
vasculitis (inflammation of vessel wall)
vascular steal ( vascular network steal blood from another network in the same organ)

Question 4

what is Virchow’s triad?

Answer 4

Factors causing thrombosis:
> changes in blood vessel wall
> changes in blood constituents
> changes in the pattern of flow

Question 5

what is thrombosis?

Answer 5

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

Question 6

describe the pathogenesis of thrombosis

Answer 6

turbulent flow > loss of intimal cells creating a denuded plaque > collagen is exposed so platelets adhere > there is a fibrin meshwork trapping red blood cells > alternating lines of zahn are created > this creates further turbulence and platelet deposition > resulting in propagation

Question 7

in what direction does the thrombus grow?

Answer 7

with the direction of flow

Question 8

in what situations may stasis blood flow occur?

Answer 8

during flight, post-operatively

Question 9

in what situations may turbulent flow occur?

Answer 9

atheromatous plaque, aortic aneurysm

Question 10

what do the consequences of thrombosis depend on?

Answer 10

> site
extent
collateral circulation

Question 11

define embolism

Answer 11

movement of abnormal material in the blood stream and its impaction in a vessel blocking its lumen

Question 12

what is an embolus?

Answer 12

detached intravascular solid, liquid or gaseous mass

Question 13

give examples of where a thromboembolism may originate from

Answer 13

> mural thrombus
aortic aneurysm
atheromatous plaques
valvular vegetation’s

Question 14

where do venous thromboembolisms originate from?

Answer 14

the deep venous thrombosis

Question 15

where may a venous thromboembolism occlude?

Answer 15

the main pulmonary artery, bifurcation, and smaller arteries

Question 16

what do the consequences of a pulmonary thromboembolism depend on?

Answer 16

size of embolism

Question 17

what may the consequences of a venous pulmonary thromboembolism include?

Answer 17

> silent
pulmonary haemorrhage/infarction
right heart failure
sudden death

Question 18

name some risk factors foe pulmonary thromboembolism

Answer 18

> cardiac failure
> severe trauma
> operations
> nephrotic syndrome
> disseminated malignancy
> oral contraception
> age
> bed rest
> obesity

Question 19

what is given as a prophylaxis for surgical patients at risk

Answer 19

TEDS

s/c heparin

Question 20

when may a fat embolism occur?

Answer 20

after a major fracture

Question 21

what can be affected in syndrome of fat embolism?

Answer 21

> brain
kidneys
skin

Question 22

describe the embolism in decompression sickness

Answer 22

this is a gas embolism and N2 forms as bubbles which lodge in the capillaries

Question 23

when may air embolisms occur?

Answer 23

> after head and neck injuries
after surgery
form CV lines

Question 24

what type of embolism may occur in pregnant ladies?

Answer 24

> trophoblasts may embolise in the lungs

> amniotic fluid in childbirth

Question 25

give an example of septic material embolising

Answer 25

infective endocarditis

Question 26

when might bone marrow embolise?

Answer 26

after a fracture

Question 27

From what may you get a foreign body embolism?

Answer 27

> intravascular cannula tips

> sutures