Bleeding Disorders

Question 1

What roles does Von Willebrand’s factor play in clotting?

Answer 1

vWF – Von Willebrand’s factor
It has 3 roles in clotting
1. Bringing platelets into contact with exposed endothelium
2. Increasing platelet-platelet binding
3. Binding factor VIII protecting it from destruction

Question 2

What is Von Willebrand’s disease?

Answer 2

Von Willebrands Disease is a clotting disorder caused by a deficiency of the Von Willebrand Factor (vWF). This results in an increased tendency to bleed. It is the most common hereditary blood clotting disorder in humans (1 in 100 people are thought to have it although only 1 in 10,000 are clinically significant with symptoms)

There are multiple types of VWD ranging from low function vWF, Low production of vWF and no production of vWF. The majority are autosomal dominant.

Question 3

How does Von Willebrand’s disease present?

Answer 3

Generally, they present with platelet type disorder with bruising, epistaxis, menorrhagia, and increasing bleeding post dental procedures.

Question 4

How should suspected von willebrand’s disease be investigated?

Answer 4

Slightly raised APTT and bleeding time (specific measurement of formation of platelet plug)
Low factor VIII

Question 5

How is Von Willebrand’s disease managed?

Answer 5

Desmopressin and tranexamic acid in minor bleeds
Avoid NSAIDs
vWF containing factor VIII concentrate for surgery or major bleeds

Question 6

What is haemophilia A?

Answer 6

Factor VIII deficiency inherited in an X-linked recessive pattern but also a high rate of new mutations (30% have no family history)

Question 7

How does haemophilia present?

Answer 7

Early in life
Post-surgery bleeding issues
Bleeding into joints – crippling arthropathy
Bleeding into muscle – haematomas leading to nerve palsies and compartment syndrome

Question 8

How should suspected haemophilia A be investigated?

Answer 8

Raised APTT but normal bleeding time (this is only a disease of secondary haemostasis)
Low Factor VIII assay

Question 9

How is haemophilia A managed?

Answer 9

Avoid NSAIDs and IM injections
Minor bleeding – compression, elevation and desmopressin (raises factor 8 levels)
Major bleeding e.g. haemarthrosis – give recombinant factor VIII reaching 50%
Life threatening bleeding i.e. obstructing airway – factor VIII reaching 100%

Genetic counselling

Question 10

What is Christmas disease?

Answer 10

Much the same as Haemophilia A but affecting factor IX. Also inherited X-linked disease.