Haematology: Von Willebrand Disease

Question 1

Von willebrand factor has what 2 major roles?

Answer 1

Facilitates platelet adhesion to damaged endothelium

Acts as the carrier protein for FVIII - protecting it from inactivation and clearance

Question 2

What does von Willebrand disease result from?

Answer 2

Either quantitative or qualitative deficiency of vWF

Question 3

What does the deficiency/ defect result in?

Answer 3

Defective platelet plug formation (vWF mediates platelet adhesion to endothelium) and factor VIII deficiency

Question 4

Why are there different types of vWD?

Answer 4

There are different mutations that can occur in the vWF gene

Question 5

Describe the usual inheritance

Answer 5

Autosomal dominant

Question 6

Describe the most common subtype

Answer 6

Type 1 60-80%

Usually fairly mild and often not diagnosed until puberty or adulthood

Question 7

Describe the clinical features

Answer 7

Platelet associated bleeding
Skin and mucous membranes bleeding - epistaxis, gum bleeding, bruising 
Prolonged bleeding after trauma 
Heavy periods
Post surgery/dental extraction bleeding

Question 8

Are spontaneous soft tissue bleeding such as large haematomas and haemarthroses common?

Answer 8

No

Question 9

What does treatment depend on?

Answer 9

Type and severity of disorder

Question 10

What can type 1 usually be treated with?

Answer 10

Desmopressin (DDAVP) - causes secretion of both factor VIII and vWF into plasma
Use with caution in children less than 1 - can cause hyponatraemia due to water retention and may cause seizures after repeated doses and if fluid intake not regulated

Question 11

How are more severe types treated?

Answer 11

Plasma derived factor VIII concentrate

DDAVP ineffective and recombinant VIII has no vWF

Question 12

What should be avoided in all patients with vWD?

Answer 12

IM injections
Aspirin
NSAIDS