Thrombosis

Question 1

Describe arterial vs venous thrombosis

Answer 1

Arterial thrombosis
Mostly result from atheroma rupture (causing MI, stroke)
Platelet-rich “white” thrombosis
Block downstream arteries

Venous thrombosis
Result from stasis or a hypercoagulant state (DVT)
Platelet-poor, “red” thrombus
May move to lungs

Question 2

Draw a diagram to briefly explain coagulation and fibrinolysis

Answer 2

Question 3

What does a DVT look like?

Answer 3

Question 4

Describe the involvement of valves in DVT

Answer 4

Blood forms circular eddy currents and collect around valves. This increases the risk of stasis and of the blood beginning to clot

So valves are a common site of thrombosis

Question 5

What is Virchow’s Triad?

Answer 5

Development of a venous thrombus depends on:

Question 6

What is meant by stasis and what its caused by? (a risk factor for thrombosis)

Answer 6

Stasis is caused by:

• Prolonged immobility e.g. surgery, travel
• Stroke, cardiac failure
• Dehydration
• Hyperviscosity
• Polycythaemia
• Stasis can also cause endothelial damage

Question 7

What is meant by hypercoagulability (risk factor for thrombosis)?

Answer 7

Hypercoagulability is caused by decreased fibrinolytic factors or anticoagulant proteins/activity:
Protein C and S deficiencies, so factor V cant be inhibited
Factor V Leiden mutation (resistance to the anticoagulant complex)

It is also caused by increased coagulation factors and platelets: eg malignancy increases clotting factors like tissue factor, FXa, thrombin

Question 8

What is meant by endothelial damage as a risk factor for thrombosis?

Answer 8

Damage to the endothelial surface will induce platelet activation and the coagulation pathway which can lead to thrombosis

Question 9

How can venous thrombosis impact the lungs?

Answer 9

In small venous thrombous can break from the clot, travel into pulmonary circulation, but it can be asymptomatic

In large venous thrombous, it can cause rapid death bc of obstruction to the circulatory system

Question 10

What is the difference between proximal and distal DVT

Answer 10

Question 11

What is post thrombotic syndrome?

Answer 11

• •Chronic complication, results from venous hypertension
• •Reduces calf muscle perfusion
• •Increases tissue permeability
• •Risk increases with obesity and age
• •Pain, swelling, oedema, redness
• •Thickening of skin
• •Ulcers in 5-10%

Question 12

Describe the treatment of VTE

Answer 12

If the patient is cardiovascularly stable with acute VTE:

• •Must initiate anticoagulation
• •Immediate anticoagulant effect: heparin then warfarin/DOAC or immediate DOAC

If the patient has circulatory collapse due to PE:

• Must initiate thrombolysis
• Alteplase (tissue plasminogen activator)
• Streptokinase
• Followed by heparin and warfarin or other to prevent recurrence

Question 13

What investigations would you do pre treatment in the investigation of thrombosis?

Answer 13

• Clotting screen
• Prothrombin time (INR), Partial thromboplastin and thrombin time
• Full blood count
• Urea and electrolytes- usually part of routine screen, to know creatinine clearance
• Liver function tests if clinical suspicion of liver disease