11 Thrombosis

Question 1

List potential sites of defect in primary haemostasis and list the symptoms associated

Answer 1

vWF, collagen (scurvy, age and steroid therapy) and platelet (caused by aspirin, thrombocytopenia)

• Immediate
• Easy bruising
• Nose bleed >20 min
• Menorrhagia
• Gum bleeding
• Bleeding after surgery
• Petechae

Question 2

List potential sites of defect in secondary haemostasis to result in bleeding and list the symptoms associated

Answer 2

Genetic: haemophilia
Acquired:
1) Liver disease
2) Drugs (warfarin)
3) Dilution
4) Consumption (DIC)

Symptoms:

• Delayed
• Prolonged
• Usually deeper: joints/muscles
• Bleeding after intramuscular injection
• Bleeding after surgery
• Nose bleed and small cuts rare as primary haemostasis is still functional

Question 3

What are the causes of excess fibrinolysis

Answer 3

Excess fibrinolysis (tPA, plasmin) - therapeutic or tumour
Deficient antifibrinolytic: antiplasmin deficiency

Question 4

What are the effects of thrombosis

Answer 4

Obstruct blood flow
- artery: stroke, MI, limb ischaemia
- vein: pain and swelling
Embolism

Question 5

What are the consequences of thrombo-embolism

Answer 5

Thrombophlebitic syndrome: swelling and ulcers in the leg due to valve damage leading to stasis
Pulmonary hypertension

Question 6

What are the predispositions of thrombosis and how do they cause increased risk of thrombosis

Answer 6

Genetics
Age
Previous events
Illnesses
Medications
Acute stimuli

Virchow’s triad: vessel wall, coagulability and flow

Question 7

What are the components of increased risk of thrombosis

Answer 7

Anti-coagulatory factor deficiency (antithrombin, protein C and S)
Increased activity of coagulatory factors (Factor 5 Leiden, thombocytosis)

Question 8

What can disturb vessel wall biochemistry and increase patient’s risk of developing thrombosis

Answer 8

Inflammation:

• Infection
• Immunological disorder
• Malignancy

Question 9

What conditions can cause stasis

Answer 9

Surgery
Bed rest
Long haul flight
Fracture

Question 10

What are the combined risk for thrombosis

Answer 10

Pregnancy
Malignancy
Surgery
Inflammation response

Question 11

What is the therapy of venous thrombosis

Answer 11

Lyse clot:
- tPA
Decrease recurrence/extension/emboli
- Heparin: increase antithrombin (anticoagulant) activity
- Warfarin: decrease coagulant factor synthesis
- Xa inhibitor (Rivaroxaban): direct inhibitor procoagulant factors