Condition- von Willebrand's disease

Question 1

State the three roles of Von Willebrand Factor

Answer 1

1. Platelet adhesion: acts as a bridge between the subendothelial layer and the platelets and allows binding via Glp1b
2. Platelet aggregation
3. Binds to F8: prevents its breakdown in the bloodstream

Question 2

Describe the three subtypes of Von Willebrand Disease and state each of their inheritance

Answer 2

• TYPE 1: reduced normal vWF (AD) 75%
• TYPE 2: defective vWF (AD) 20%
• TYPE 3: No vWF + highly reduced F8 (AR) 1-5%

Question 3

State some of the presenting symptoms of Von Willebrand’s disease

Answer 3

Symptoms more similar to platelet disorder (superficial bleeding) than Haemophilias

• Easy bruising
• Epistaxis, Gingival bleed
• Menorrhagia, GI bleed

Question 4

How does Type 3 vWF tend to present? and why?

Answer 4

With deeper bleeding like haemarthrosis and haematomas

Due to massive reduction in F8 (so it acts more like haemophilias)

Question 5

What might you see in the bloods of someone with vWF?

• platelet
• clotting screen

Answer 5

• Normal platelets + INR
• Reduced vWF assay in T1+T3, normal T2
• Prolonged APTT normal PT (intrinsic pathway)
• Increased bleeding time

Question 6

vWF binds to and protects which clotting factor from degradiation in the bloodstream?

Answer 6

Factor 8