Thrombotic Disorders

Question 1

What are the 2 pathways involved in fibrinolysis and what are the activators/enzymes involved?

Answer 1

Extrinsic pathway - Tissue Plasminogen activator (TPA)

Intrinsic pathway - Factor XII

Question 2

What do TPA and Factor XII react with in order to create plasmin?

Answer 2

Plasminogen

Question 3

What does plasmin react with in order to create fibrinogen and fibrinogen breakdown products (e.g D-dimer)?

Answer 3

Fibrin

Question 4

Draw a simplified version of the fibrinolysis pathway

Answer 4

Question 5

What is a thrombus?

Answer 5

A clot arising in the wrong place

Question 6

What is meant by the term thromboembolism?

Answer 6

Movement of a clot along a vessel

Question 7

Draw Virchows Triad

Answer 7

Question 8

What can cause problems with each component of Virchows Triad?

Answer 8

Stasis - Bed rest or Travel

Vessel Damage - Atherosclerosis

Hypercoagulability - Pregnancy or Trauma

Question 9

What are the 3 locations in which thrombosis can occur?

Answer 9

1 - Arterial

2 - Venous

3 - Microvasculature

Question 10

What is the most likely primary cause of an arterial thrombus?

Answer 10

Atherosclerosis

Question 11

What are consequences of an arterial thrombus?

Answer 11

Ischaemia

Infarction

Question 12

What are the most common types of arterial thromboembolism?

Answer 12

1) Coronary Thromboembolism
2) Cerebrovascular Thromboembolism
3) Peripheral Embolism

Question 13

What conditions can occur due to a coronary thromboembolism?

Answer 13

MI

Unstable angina

Question 14

What conditions can occur due to a cerebrovascular thromboembolism?

Answer 14

1) Stroke
2) TIA

Question 15

What conditions can occur due to a peripheral thromboembolism?

Answer 15

1) Limb Ischaemia

Question 16

What are the risk factors for arterial thromboembolism?

Answer 16

1) Smoking
2) Age
3) Sedentary lifestyle
4) Hypertension
5) Obesity
6) Diabetes Mellitus
7) High cholesterol

Question 17

How are arterial thromboemboli’ primarily prevented?

Answer 17

1 - Lifestyle modification

2 - Treatment of vascular risk factors

Question 18

How are arterial thromboemobli managed in an acute presentation?

Answer 18

1) Thrombolysis
2) Antiplatelet (aspirin/ticagrelor)/anticoagulant (warfarin/LMWH) drugs

Question 19

What are the constituents of an arterial thrombus?

Answer 19

Platelets

Fibrin

Question 20

What are the constituents of venous thrombus?

Answer 20

Red cells

Fibrin

Question 21

What is the main physiological effect of venous thrombi’?

Answer 21

Back pressure

Question 22

Thinking of Virchows Triad, what are the main causes of venous thrombus’?

Answer 22

Stasis

Hypercoagulability

Question 23

What are the most common types of venous thromboembolism?

Answer 23

Deep vein thrombosus

Pulmonary embolism

Question 24

What factors can affect stasis and hypercoagulability that both contribute to venous thromboembolisms?

Answer 24

1 - Immobility

2 - Surgery

3 - Obesity

4 - Pregnancy

5 - COCP/HRT

6 - Increasing age

Question 25

What systemic diseases are associated with an increased risk of venous thrombosis?

Answer 25

1 - Cancer 2 - Myeloproliferative Neoplasm 3 - Inflammatory bowel disease 4 - SLE

Question 26

What are the 2 pretest scoring methods used to indicate the likelihood of a venous thrombosis?

Answer 26

1 - Wells score 2 - Geneva score

Question 27

Which pretest scoring method is best for diagnosing DVT's?

Answer 27

Wells score

Question 28

Which pretest scoring method is best for diagnosing PE's?

Answer 28

Geneva score

Question 29

What lab testing will be performed if the pretest probability score was low?

Answer 29

D-dimer

Question 30

What sensitivity and specificity does the D-dimer test have?

Answer 30

Highly sensitive Not specific

Question 31

If the D-dimer result is low, what is the next step?

Answer 31

Imaging

Question 32

If the pretest probability score is high, what would be the next step?

Answer 32

Imaging No need for D-dimer test

Question 33

What imaging modalities are used to diagnose venous thromboembolisms?

Answer 33

Compression Doppler USS V/Q perfusion scan CT Pulmonary Angiogram

Question 34

What would be the features of a DVT on compresison doppler USS?

Answer 34

1 - Thrombosed vein enlarged 2 - Thrombosed vein non-compressible

Question 35

What are the features of a PE on a V/Q perfusion scan?

Answer 35

Mismatch between perfusion and ventilation

Question 36

What scan must be performed before doing a V/Q perfusion scan?

Answer 36

The patient must have a normal X-ray scan

Question 37

What is the gold standard imaging method for PE's?

Answer 37

CT Pulmonary Angiogram

Question 38

What are the aims of management of DVT's/PE's?

Answer 38

1 - Prevent clot extension 2 - Prevent clot embolisation 3 - Prevent clot recurrence in long term

Question 39

What are the anticoagulant drugs used to treat DVT/PE's?

Answer 39

Anticoagulants - Warfarin, LMWH or DOAC's Thrombolysis for massive PE's

Question 40

What are the most common heritable thrombophilias?

Answer 40

1 - Factor V Leiden 2 - Prothrombin G202

Question 41

What does Factor V Leiden cause?

Answer 41

An increase in clotting, i.e. a hypercoagulable state

Question 42

What protein is affected by Factor V Leiden mutation?

Answer 42

Protein C

Question 43

To which group of patients is thrombophilia screening useful?

Answer 43

Antithrombin deficiency

Question 44

What sort of ischaemia is present with microvascular thrombus?

Answer 44

Diffuse ischaemia

Question 45

In what condition are microvascular thrombus' most common?

Answer 45

Disseminated Intravascular Coagulation (DIC)

Question 46

In what conditions is DIC most commonly seen?

Answer 46

1 - Septicaemia 2 - Malignancy 3 - Eclampsia