Bleeding Disorders + Thrombophilia

Question 1

What is the most common cause of primary haemostatic failure?

Answer 1

Thrombocytopenia (usually acquired)

Question 2

What are the two main mechanisms of thrombocytopenia?

Answer 2

Reduced production –> marrow problem

Increased destruction –> DIC, ITP, hypersplenism

Question 3

What might cause function defects in platelets?

Answer 3

Drugs e.g. aspirin, NSAIDs

Renal failure

Question 4

How is vWF deficiency inherited?

Answer 4

Autosomal dominant

Question 5

Which conditions may cause a multiple factor deficiency?

Answer 5

Liver failure
Vitamin K deficiency / warfarin therapy
DIC

Question 6

How would PT and APTT be affected by a multiple factor deficiency?

Answer 6

Both would be prolonged

Question 7

Where are coagulation factors synthesised?

Answer 7

Hepatocytes (reduced in liver failure)

Question 8

Which factors are carboxylated by vitamin K?

Answer 8

2, 7, 9, 10

Question 9

What are the causes of vitamin K deficiency?

Answer 9

Poor dietary intake
Malabsorption
Obstructive jaundice (bile required for absorption)
Warfarin (vitamin K antagonist)
Haemorrhagic disease of newborn

Question 10

What is DIC?

Answer 10

Excessive + inappropriate activation of the haemostatic system –> primary, secondary + fibrinolysis

Question 11

What are the features of DIC?

Answer 11

Microvascular thrombus formation –> end organ failure

Clotting factor consumption –> bruising, purpura + generalised bleeding

Question 12

What are some causes of DIC?

Answer 12

Sepsis
Obstetric emergencies
Malignancies
Hypovolaemic shock

Question 13

How is DIC managed?

Answer 13

Treat underlying cause
Platelet + plasma transfusions
Fibrinogen replacement

Question 14

What is the pattern of inheritance of haemophilia?

Answer 14

X-linked

Question 15

Which type of haemophilia is most common?

Answer 15

Haemophilia A

Question 16

What causes the bleeding in haemophilia A?

Answer 16

Factor 8 deficiency

Question 17

What causes the bleeding in haemophilia B?

Answer 17

Factor 9 deficiency

Question 18

What are the features of haemophilia?

Answer 18

Haemarthrosis
Haematoma in muscles
Intracranial haemorrhage
Prolonged bleeding after procedure/dental work

Question 19

Which blood result would be suggestive of haemophilia?

Answer 19

Isolated prolonged APTT

PT not affected

Question 20

How is haemophilia A managed?

Answer 20

Avoid contact sport
IV factor 8 concentrate
- weekly for prophylaxis or until bleeding stops if acute
Desmopressin 
- for acute bleeds in mild haemophilia

Question 21

What is INR?

Answer 21

Standardised norm for PT

Question 22

How do the clots differ between arterial and venous thrombosis?

Answer 22

Arterial:
- high pressure, atherosclerosis
- platelet rich thrombus
Venous:
- low pressure so platelets not activated
- coagulation cascade –> fibrin rich clot

Question 23

Which drugs are used to treat arterial thrombosis?

Answer 23

Aspirin + other anti-platelets

Question 24

Which drugs are used to treat venous thrombosis?

Answer 24

Heparin, warfarin + DOACs

Question 25

What is thrombophilia?

Answer 25

Disorder (inherited or acquired) which predisposes to thrombosis

Question 26

Give some examples of hereditary thrombophilias

Answer 26

``` Factor 5/Leiden Prothrombin 20210 mutation Antithrombin deficiency Protein C deficiency Protein S deficiency ```

Question 27

When should you consider screening for inherited thrombophilias?

Answer 27

Venous thrombosis < 45 years old Recurrent venous thrombosis Usual venous thrombosis FHx of venous thrombosis/thrombophilia

Question 28

Give an example of an acquired thrombophilia?

Answer 28

Antiphospholipid antibody syndrome

Question 29

What are the features of antiphospholipid antibody syndrome?

Answer 29

Recurrent arterial and venous thrombosis Recurrent foetal loss Mild thrombocytopenia

Question 30

Which drugs are used to manage antiphospholipid antibody syndrome?

Answer 30

Aspirin + warfarin | --> as activation of both primary + secondary haemostasis