Pathophysiology of Thrombosis and Embolism

Question 1

Describe the process of thrombosis

Answer 1

• Endothelial injury
• Stasis or turbulent blood flow
• Hypercoagulability of the blood

Question 2

Explain the significance of Virchow’s triad (i.e. list the factors causing thrombosis)

Answer 2

= FACTORS CAUSING THROMBOSIS

• Changes in the blood vessel wall
• Changes in the blood constituents
• Changes in the pattern of blood flow (STASIS - stagnant of flow or TURBULENCE - forceful, unpredictable flow)

Question 3

Explain the relationship between atheroma and thrombosis

Answer 3

arterial thrombosis most commonly superimposed (form on top of) on atheroma; Virchow’s triad

Question 4

List the factors causing embolism

Answer 4

Depends on type of embolism

Cardiac failure, severe trauma/burns, post-op/post-partum, nephrotic syndrome, disseminated malignancy, oral contraceptive,  age, bed rest/immobilisation, obesity, PMH of DVT

Prophylaxis for surgical patients at risk: TEDS, s/c heparin

Question 5

What is thrombosis?

Answer 5

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

Question 6

What are the consequences of thrombosis?

Answer 6

• Site
• Extent
• Collateral circulation

Question 7

Define embolism

Answer 7

Movement of abnormal material in the bloodstream and its impaction in a vessel, blocking its lumen (can be solid, liquid or gaseous mass)

MOST EMBOLI ARE DISLODGED THROMBI

Question 8

Name the types of embolism

Answer 8

• Systemic/arterial thromboembolus
• Venous thromboembolus
• Fat
• Gas
• Air
• Tumour
• Trophoblast
• Septic material
• Mniotic fluid
• Bone marrow
• Foreign bodies

Question 9

SYSTEMIC/ARTERIAL thromboembolus

Answer 9

Travel to wide variety of sites: lower limbs most common, brain, other organs

Consequences depend on vulnerability of affected tissues to ischaemia, calibre of occluded vessel, collateral circulation but usually infarction occurs

Question 10

VENOUS thromboembolus

Answer 10

Originate from deep venous thromboses (lower limbs)

Most common form of thromboembolic disease

Travel to the pulmonary arterial circulation

Depending on size, may occlude main pulmonary artery, bifurcation (saddle embolus), smaller arteries

Often multiple

Consequences of pulmonary thromboembolism depend on size of embolus: silent, pulmonary haemorrhage/infarction, right heart failure, sudden death

Question 11

FAT embolus

Answer 11

After major fractures
Syndrome of fat embolism: brain, kidneys, skin affected