Bleeding Disorders

Question 1

What are vascular abnormalities that can affect bleeding?

Answer 1

Hereditary
Acquired - vasculitis (Henoch Schonlein purpura)

Question 2

What are acquired causes of thrombocytopenia?

Answer 2

Reduced production (marrow problem)
Increased destruction

Question 3

What are causes of peripheral platelet destruction?

Answer 3

Coagulopathy - disseminated intravascular coagulation (DIC)

Autoimmune - immune thrombocytopenic purpura (ITP)

Hypersplenism

Question 4

What are acquired platelet functional defects?

Answer 4

Drugs (e.g. aspirin, NSAIDs)
Renal failure

Question 5

Von willebrand factor deficiency is acquired how?

Answer 5

Autosomal dominant
Common
Variable severity -. usually mild

Question 6

What is the commonest cause of primary haemostatic failure?

Answer 6

Thrombocytopenia

Usually acquired

Causes: marrow failure, peripheral destruction

Question 7

What are causes of multiple factor deficiencies which then causes failure of fibrin clot formation?

Answer 7

Liver failure
Vitamin K deficiency / warfarin therapy
Complex coagulopathy (DIC)

Prolonged APTT + PT

Question 8

All coagulation factors are synthesised where?

Answer 8

In hepatocytes, so these are reduced in liver failure

Question 9

What clotting factors are carboxylated by vitamin K, which is essential for function?

Answer 9

1972
(factors II, VII, IX, X)

Question 10

What are sources of vitamin K?

Answer 10

Diet
Intestinal synthesis (by bacteria)

Question 11

How do we absorb vitamin K?

Answer 11

Absorbed upper intestine
Requires bile salts for absorption

Question 12

What are causes of vitamin K deficiency?

Answer 12

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

Question 13

What is disseminated intravascular coagulation?

Answer 13

Excessive and inappropriate activation of haemostatic system (primary, secondary, fibrinolysis)
Microvascular thrombus formation (end organ failure)
Clotting factor consumption (bruising, purpura, generalised bleeding)

Question 14

What are causes of DIC?

Answer 14

Sepsis
Obstructive emergencies
Malignancy
Hypovolaemic shock

Question 15

How do we treat DIC?

Answer 15

Treat underlying cause
Replacement therapy - platelet transfusions, plasma transfusions, fibrinogen replacement

Question 16

What is haemophilia?

Answer 16

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

Question 17

What are the main types of haemophilia?

Answer 17

Haemophilia A (factor VIII deficiency) -5x more common

Haemophilia B (Factor IX deficiency)

Question 18

What is the pathophysiology of haemophilia?

Answer 18

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

Question 19

What are clinical features of severe haemophilia?

Answer 19

Recurrent haemarthroses
Recurrent soft tissue bleeds (bruising in toddlers)
Prolonged bleeding after dental extractions, surgery and invasive procedures

Question 20

Haemophilia A and B have what prolonged test?

Answer 20

Isolated prolonged APTT