Pathophysiology of Thrombosis Flashcards
(27 cards)
what is stasis of blood flow?
stagnation of flow
what is turbulent blood flow?
forceful, unpredictable flow
name some other causes of defects in blood flow
> 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)
what is Virchow’s triad?
Factors causing thrombosis:
> changes in blood vessel wall
> changes in blood constituents
> changes in the pattern of flow
what is thrombosis?
formation of a solid mass from constituents of blood within the vascular system during life
describe the pathogenesis of thrombosis
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
in what direction does the thrombus grow?
with the direction of flow
in what situations may stasis blood flow occur?
during flight, post-operatively
in what situations may turbulent flow occur?
atheromatous plaque, aortic aneurysm
what do the consequences of thrombosis depend on?
> site
extent
collateral circulation
define embolism
movement of abnormal material in the blood stream and its impaction in a vessel blocking its lumen
what is an embolus?
detached intravascular solid, liquid or gaseous mass
give examples of where a thromboembolism may originate from
> mural thrombus
aortic aneurysm
atheromatous plaques
valvular vegetation’s
where do venous thromboembolisms originate from?
the deep venous thrombosis
where may a venous thromboembolism occlude?
the main pulmonary artery, bifurcation, and smaller arteries
what do the consequences of a pulmonary thromboembolism depend on?
size of embolism
what may the consequences of a venous pulmonary thromboembolism include?
> silent
pulmonary haemorrhage/infarction
right heart failure
sudden death
name some risk factors foe pulmonary thromboembolism
> cardiac failure > severe trauma > operations > nephrotic syndrome > disseminated malignancy > oral contraception > age > bed rest > obesity
what is given as a prophylaxis for surgical patients at risk
TEDS
s/c heparin
when may a fat embolism occur?
after a major fracture
what can be affected in syndrome of fat embolism?
> brain
kidneys
skin
describe the embolism in decompression sickness
this is a gas embolism and N2 forms as bubbles which lodge in the capillaries
when may air embolisms occur?
> after head and neck injuries
after surgery
form CV lines
what type of embolism may occur in pregnant ladies?
> trophoblasts may embolise in the lungs
> amniotic fluid in childbirth
