Pathophysiology of Thrombosis and embolism

Question 1

What is meant by laminar blood flow?

Answer 1

-Normal blood flow of blood that moves parallel and

Question 2

Types of abnormal blood flow

Answer 2

Stasis
-stagnation of flow

Turbulence
-forceful, unpredictable flow

Question 3

State conditions that may affect blood flow

Answer 3

• thromb embolism
• atheroma
• hyperviscosity, spasm
• external compression
• vasculitis
• vascular steal

Question 4

State Virchow’s triad

Answer 4

Factors causing thrombosis

• changes in BV wall
• changes in blood constituents
• changes in pattern of blood flow

Question 5

Describe the pathogenesis of thrombosis

Answer 5

• Endothelial injury
• stasis OR turbulent blood flow
• hypercoagulability of blood

(Virchows triad)

Question 6

Describe pathogenesis of thrombosis in an athermatous coronary artery

Answer 6

-turbulent blood flow ( fibrin deposition, platelet clumping)
-loss of intimal cells, rupture occurs an collagen is exposed + platelets will adhere
-fibrin meshwork, RBCs will be trapped + alternating bands ( linez of zahn) formed?
-

Question 7

Examples of changes in vessel wall

Answer 7

atheromatous coroanry artery

-hypercholesterolaemia

Question 8

Changes in blood constituents examples

Answer 8

• hypervisccity

- post traumatic hypercoaguability

Question 9

Changes in blood flow examples

Answer 9

• stasis ‘’ ecconomy class syndrome ‘’ post op

- turbulence; atheramatous plaque, aortic aneurysm

Question 10

What is an embolism?

Answer 10

-movement of abnormal material in bloodstream and may block vessels lumen

Question 11

What is an embolus?

Answer 11

-detached intravascular solid/liquid/gaseous mass

Question 12

Sources of systemic/arterial thromboembolus

Answer 12

• mural thrombus ; adheres the vessel wall ( associated with MI/ left atrial dilation + atrifal fibrilation)
• aortic aneurtysms
• atheromatous plaques
• valvular vegetations ( venous thrombi - paradocical emboli)

Question 13

Systemic thromboembolus

Answer 13

• mainly travels to lower limbs, brain + other organs

- can lead to ischaemia, calibre of occluded vessel, collateral circulation + infarction

Question 14

Types of embolus

Answer 14

• systemic/arterial thromboembolus
• venous thromboembolus
• fat
• gas
• air
• tumour
• trophoblast
• septic material
• amniotic fluid
• bone marrow
• foreign bodies

Question 15

Venous thromboembolus

Answer 15

• originates from deep venous thromboses ( lower limbs)
• travels to pulmonary arterial circulation
• can cause occlusion of main pulmonary artery, bifurcation( saddle embolus), smaller arteries
• most common form of thromboemmbolic disease

Question 16

Consequences of pulmonary thromboembolisk

Answer 16

• silent, pulmonary hamorrhage/infaction, right heart failure, sudden death
• if multiple over time > pulmonary hypertension and RVF

Question 17

Risk factors for DVT and pulmonary thromboembolism

Answer 17

-cardiac failure, severe trauma/burns, post op/post partum, nephrotic sundrome, disseminated malignancy, oral contraceptive, age, bed rest/immbolisation, obesity, PMH

Question 18

Surgical patients at risk of DVT/pulmonary thromboembolism

Answer 18

recieve prophylacis : TEDS, s/c heparin

Question 19

When may a fat embolis occur?

Answer 19

• after major fracture

- sundrome of fat embolism: brain, kidneys and skin is affected

Question 20

When may a gas embolus occur?

Answer 20

• if you have decompression sickness; N2 forms as bubbles which lodges in brain capillaries
• air embolus due to head, neck wounds, surgery + CV lines

Question 21

Examples of trophoblast and septic material in association with embolus

Answer 21

Trophoblast - pregnant women > lungs

Septic material - infective endocarditis

Question 22

Why may amniotic fluid, bone marrow + foregin bodies be an embolus?

Answer 22

amniotic fluid - cause of collapse and can cause death in child birth

Bone marrow - fractures; CPR

Forwign bodies - intravascular cannulae tipes, sutures

Question 23

What is rheumatic fever?

Answer 23

• disease of disordered immunity
• inflammatory changes in heart,joints + has neurological symptoms
• affects children 5-15 years, boys>girls

Question 24

Presentation of rheumatic fever

Answer 24

• polyarthritiss of large joints + skin rashes + dever

- pancarditis ( inflammation of endocardium, myocardium AND pericardium) and in acute; heart murmurs will be common

Question 25

Pathophysiology of rheumatic fever

Answer 25

• Beta group A haemolytic strep infection
• strong antibody reaction to strep which may cross react with unknown antigens in connective tissues
• damage to heart tissue may be caused by combination of antibody mediated and T cell mediated reactions

Question 26

What is an Aschoff body

Answer 26

• a focus of chronic inflammatory cells, necrosis and activated macrophages
• seen in the heart in acute rheumatic fever

Question 27

Vegatations of heart disease may lead to what?

Answer 27

-can be infective/thrombotic nodules which develop in valave leaflets impairing the normal valve mobility. Can also embolise

Question 28

Effect of pancarditis

Answer 28

• acute can > chronic rheumatic heart disease which affects valves
• inflammation of endocardium + left sided valves results in fibrinoid necrosis of the valve/cusps/chordae tendinae which ( along with line of closure ) forms small vegetations

-fibrotic valvvular disease ( mainly valve ) will involve leaflet thickening, commissural fusion + shortening, thicening + fusion of chordae tendinae

Question 29

What is rheumatic HD

Answer 29

-main cause of mitrals tenosis and can cause mitral regurigation

Question 30

add to valvular HD lecture

Answer 30

Can cause mitral regurgitation but now most commonly due to ischaemic heart disease
Now only rarely causes aortic stenosis – most due to calcific aortic valve disease
Potentially still causes aortic regurgitation/incompetence
Tricuspid valve involvement infrequent; pulmonary valve involvement rare