Von Willebrand disease (VWD) is the most common inherited bleeding disorder.
People with VWD either have a deficiency of a blood protein called von Willebrand factor, or this protein doesn't work properly. It means that their blood cannot clot properly and they are prone to bleeding.
Von Willebrand factor acts like a glue to make platelets (a type of blood cell) clump together and plug up damaged blood vessels. This is essential for clotting.
Another function of von Willebrand factor is to carry a clotting protein called factor VIII.
What are the symptoms?
Many people with VWD will experience:
- abnormally heavy periods (in women)
- easy and unusual bruising
- bleeding in the gums, nose and lining of the gut
- prolonged bleeding from cuts
- excessive bleeding after tooth extraction or surgery
For most people, the symptoms of VWD are so mild that they may never know they have it. About 1-2% of the UK population have reduced levels of von Willebrand factor, but only about 1 in 1000 people have symptoms that might require medical attention.
Even people with more severe symptoms can go on to lead normal and active lives with treatment.
What causes VWD?
VWD is a genetic condition – the child inherits an abnormal gene from one or both parents.
There are four different types of VWD. The condition is classified according to the amount and function of the Willebrand factor in the blood:
- Type 1 – The mildest and most common type. People with type 1 VWD have a reduced level of von Willebrand factor in their blood. Symptoms might be so mild that they never know they have VWD. They don't usually bleed spontaneously, but can bleed significantly if they have surgery, injure themselves or have a tooth pulled.
- Type 2 – In this type, the von Willebrand factor doesn't work properly. Treatment differs depending on which type 2 VWD you have.
- Type 3 - People with this type have very low levels of von Willebrand factor in their blood, or none at all. It is a severe bleeding disorder similar to haemophilia. Bleeding from the mouth, nose and bowel from an early age is typical, and joint and muscle bleeds can occur after injury. Type 3 VWD is very rare.
- Pseudo, or platelet type – this is similar to type 2, but instead of the abnormality occuring in the von Willebrand factor, it occurs in the platelets.
Types 1 and 2 VWD are often passed on through 'dominant inheritance'. This means that even if only one parent has the gene and passes it to their child, the child will have the disorder. This is not always the case in milder type 1 disease, where inheritance is less predictable.
Type 3 VWD is passed on through 'recessive inheritance'. This means the child needs to inherit the abnormal gene from both parents (which is why it's much less common). The parents who are genetic 'carriers' of the VWD usually have no bleeding symptoms themselves and may or may not have reduced levels of von Willebrand protein in the blood.
How is VWD diagnosed?
The symptoms of VWD can be mild and this can mean it is sometimes difficult to diagnose.
A blood test can help confirm the diagnosis. Occasionally, these tests have to be repeated because levels of von Willebrand factor can vary over time. The doctor will also ask about a child's family history to see if any other members of the family have a bleeding disorder.
Someone with suspected VWD should be referred to a haematologist (specialist in diagnosing and treating disorders of the blood).
How is VWD managed?
Mild bleeding might not need any treatment, and you may be able to manage the disease by taking special precautions and making a few lifestyle changes.
Otherwise, three main treatments are available to either prevent or treat bleeding:
- [desmopressin] – a nasal spray or injection
- tranexamic acid – mouthwash, tablets or an injection
- [von Willebrand factor replacement]) – this is purified from human plasma (from donated blood) and is given as an infusion directly into the vein
Your doctor will explain which medication is suitable for you and when you should take it.
Sometimes, your doctor may recommend a 'test dose' of desmopressin to check that it works well. Common side effects include flushing (a feeling of blood rushing to the face and skin), a fast heartbeat, and sometimes a mild headache. It can cause fluid retention for up to 24 hours, so your doctor will ask you to restrict the amount of fluid you drink after treatment.
Some advice on the use of these medications is given below, along with general lifestyle changes you can make.
Most people with VWD have the mildest type, type 1, and may not even realise they have it. They can live normal and active lives and take part in most sports and activities.
In severe cases, contact sports should be avoided and caution is needed for certain activities. Protective equipment should also be worn for certain activities.
People with VWD should avoid taking aspirin and non-steroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen, as these might make the condition worse.
If someone with VWD has an accident or is scheduled for surgery, it is important that the doctor is aware the person has the condition.
Due to the risk of excessive bleeding, boys at risk of VWD should not be circumcised without first speaking to a doctor.
Managing heavy periods
Girls with VWD who have heavy periods might want to carry extra pads or even a change of clothes in case of accidents.
They should get advice from their doctor or gynaecologist about options to control their bleeding, these include:
- the oral contraceptive pill
- a tablet called tranexamic acid
- an intrauterine device (IUD)
- less commonly, a [desmopressin] nasal spray
- in severe cases, VWF concentrate
Managing nosebleeds and other injuries
If bleeding does occur, applying pressure to the area may be all that's needed. Someone who gets a nosebleed should put pressure on the bridge of the nose to help stop the bleeding.
Preventing bleeding before dental procedures or surgery
People with type 1 VWD can usually be treated with [desmopressin] before dental procedures or surgery.
Desmopressin temporarily boosts levels of von Willebrand factor just long enough to prevent bleeding during the procedure. It can be given into the vein, under the skin (subcutaneous) or sometimes as a nasal spray. Tranexamic acid is often given in addition to desmopressin.
This may or may not be helpful for treating people with some forms of type 2 VWD, and is not at all effective in type 3 VWD, as there are no levels of von Willebrand factor to boost.
Preventing bleeding before major surgery or treating severe injury
People with type 3 (and most with type 2) VWD disease will need to take von Willebrand factor concentrate before they have major surgery. This contains both von Willebrand factor and factor VIII (another clotting protein). It is given intravenously (injected into a vein).
Patients with type 1 also might need factor concentrate after a severe injury or before major surgery, although they can generally be treated with desmopressin and tranexamic acid.