Bleeding Disorders

Question 1

What is involved in factor V/Xa activation?

Answer 1

TF/VIIa and VIII/IVa

Question 2

What converts prothrombin to thrombin?

Answer 2

V/Xa

Question 3

What vascular abnormalities can cause failure of platelet plug formation?

Answer 3

Hereditary

Acquired- vasculitis e.g. HS Purpura

Question 4

What are the overall causes of an acquired thrombocytopenia?

Answer 4

Reduced production (marrow problem)
Increased destruction

Question 5

What are some causes of peripheral platelet destruction?

Answer 5

Coagulopathy- Disseminated intravascular coagulation
Autoimmune- Immune thrombocytopenic purpura (ITP)
Hypersplenism

Question 6

What are some acquired causes of platelet functional defects?

Answer 6

Drugs e.g. aspirin, NSAIDs

Renal failure

Question 7

What is a hereditary cause of thrombocytopenia?

Answer 7

vWF deficiency- AD, common, variable severity but generally mild

Question 8

What is the commonest cause of 1’ haemostatic failure?

Answer 8

Thrombocytopenia

Question 9

What can cause multiple factor deficiencies causing failure of fibrin clot formation?

Answer 9

Liver failure
Vitamin K Deficiency/Warfarin therapy
Complex coagulopathy- Disseminated intravascular coagulation

Question 10

What are all coagulation factors synthesised in?

Answer 10

Hepatocytes, therefore reduced in liver failure

Question 11

What factors are carboxylated by vit K, essential for their function?

Answer 11

II, VII, IX and X

Question 12

Describe vit K sources and absorption

Answer 12

Sources- Diet, intestinal synthesis
Absorbed in upper intestine
Requires bile salts for absorption

Question 13

What are some causes of vit K deficiency?

Answer 13

Poor dietary intake
Malabsorption
Obstructive jaundice
Vitamin K antagonists (warfarin)
Haemorrhagic disease of the newborn

Question 14

What occurs in DIC?

Answer 14

Excessive and inappropriate activation of the haemostatic system- Primary, secondary and fibrinolysis
Microvascular thrombus formation- end organ failure
Clotting factor consumption- Bruising, purpura and generalised bleeding

Question 15

What are some causes of DIC?

Answer 15

Sepsis
Obstetric emergencies
Malignancy
Hypovolaemic shock

Question 16

What is the treatment of DIC?

Answer 16

Treat the underlying cause
Replacement  therapy:
Platelet transfusions
Plasma transfusions
Fibrinogen replacement

Question 17

What is Haemophilia?

Answer 17

X-linked, hereditary disorder in which abnormally prolonged bleeding recurs episodically at one or a few sites on each occasion

Question 18

What is Haemophilia A and B?

Answer 18

A: factor VIII deficiency
B: factor IX deficiency
A is 5x as common as B

Question 19

Describe haemophilia in terms of haemostasis and bleeding

Answer 19

No abnormality of primary Haemostasis
Bleeding from medium to large blood vessels
Mild moderate and severely affected families depending on factor VIII/IX level

Question 20

What are the clinical features of severe haemophilia?

Answer 20

Recurrent Haemarthroses
Recurrent soft tissue bleeds- bruising in toddlers
Prolonged bleeding after dental extractions, surgery and invasive procedures