Von Willebrand’s disease (vWD) is the most common inherited bleeding disorder. It affects between one and two per cent of the population.
VWD affects men and women equally and there is no relation to a particular ethnic group.
People with vWD have a deficiency of von Willebrand factor. This is a protein in the blood that acts like a glue to make platelets clump together and stick to damaged blood cells. This is essential for normal blood clotting.
Another function of von Willebrand factor is to carry a clotting protein called factor VIII.
For most people, the symptoms of vWD are so mild that they may never know they have it. For others, the symptoms can be more severe. But with proper diagnosis and treatment, they can go on to lead normal and active lives.
What causes vWD?
Because vWD is a genetic condition, it is inherited from a gene passed on by one or both parents.
There are four different types of vWD. The condition is classified according to the level of normal vWF molecules.
- Type 1 – people with type 1 vWD have a reduced level of von Willebrand’s factor in their blood. The symptoms might be so mild that they never know they have the condition. People with type 1 vWD do not usually bleed spontaneously. But they can sometimes have significant bleeding if they have surgery, trauma or when they have a tooth pulled.
- Type 2 – in this type the von Willebrand factor is functionally abnormal. There are two kinds of vWD within this type called type 2A and type 2B. Other type 2 subtypes exist but these are very rare.
- Type 3 – people with this the type have a very low or absent von Willebrand factor in their blood. It is a severe bleeding disorder and can result in bleeding similar to that seen in severe haemophilia but with an increased tendency to dramatic mouth/nose bleeding. This type is very rare.
- Pseudo, or platelet-type – this is similar to type 2B but instead of the abnormality occurring in the von Willebrand factor, it occurs in the platelets.
Children with types 1 and 2 vWD usually inherit the faulty gene from one of their parents, in type 3, the child usually inherits the gene from both parents.
What are the signs and symptoms of vWD disease?
The signs and symptoms of vWD can include any of the following:
- abnormal menstrual bleeding
- easy and unusual bruising
- bleeding in the gums, nose and lining of the gastrointestinal system
- excessive or prolonged bleeding from cuts or when a tooth is removed
How is vWD normally diagnosed?
Because the symptoms of vWD can be mild, it is sometimes difficult to diagnose.
A blood test can confirm diagnosis. Occasionally these tests have to be repeated because levels can vary over time. The doctor will also ask about a child’s family history to see if another member of the family has a bleeding disorder.
How is vWD normally treated?
Treatment prescribed will depend upon the severity of disease and the bleeding event – for example if it is surgery or trauma related.
There are three treatments commonly used for vWD: tranexamic acid (given orally or intravenously) desmopressin (DDAVP given intravenously or inhaled) or a vWD factor replacement (known as Wilate or Haemate P and given intravenously).
People who have vWD should avoid taking nonsteroidal anti-inflammatory drugs (NSAIDs), such as aspirin or ibuprofen, as these can make the condition worse.
What happens next?
Children with vWD can live normal and active lives and take part in most sports and activities. In severe cases however, contact sports should be avoided and caution needed for certain activities. Protective equipment should also be worn for certain activities.
If a child has an accident or is scheduled for surgery, it is important the doctor is aware the child has the condition.
Because of the risk of excessive bleeding, male children at risk of vWD should not be circumcised without first speaking to a doctor.
For girls with vWD who have heavy menstrual periods, bleeding can sometimes be controlled with tranexamic acid and/or birth control pills.