Coagulation, Thrombosis, Embolism

Question 1

Where do arterial emboli tend to lodge?

Answer 1

Lower limbs (75%), brain (10%), intestine, kidneys, spleen, upper limbs

Question 2

What factors predispose to thrombus formation in a vessel?

Answer 2

Virchow’s triad:

Endothelial injury

Stasis or turbulence of bloodflow

Hypercoagulable state

Question 3

How are hypercoagulable states categorised?

Answer 3

Primary (genetic): Factor V Leiden deficiency, Factor II mutation, Antithrombin III deficiency

Secondary (acquired): Antiphospholipid antibodies, Pregnancy, Pre-eclampsia, DIC, Prolonged immobilisation, AF, Cancer, HITS

(Name both categories, 2 examples from Primary, 3 examples from Secondary)

Question 4

What are the possible outcomes for a vessel thrombus?

Answer 4

Growth - occlusion

Embolisation

Resolution - fibrinolysis

Organisation and recanalisation

(2 of these 4)

Question 5

What are the pathological consequences of DIC?

Answer 5

Microthrombi - multi-organ ischaemia

Consumptive coagulopathy - thrombocytopaenia

leading to a Bleeding diathesis

Question 6

What are the causes of DIC?

Answer 6

Sepsis

Obstetric - pre-eclampsia, FDIU

Trauma - including snake bite

Malignancy

(3/4 categories to pass)

Question 7

What is the process of DIC?

Answer 7

Disseminated Intravascular Coagulation.

Consumptive coagulopathy (thrombocytopaenia, increased fibrin degradation products)

• Procoagulant state
• Release of Tissue Factor from beneath damaged endothelium
• Plasminogen activator inhibitor (prevents fibrinolysis)