General information about von Willebrand's disease
Introduction
von Willebrand’s Disease (VWD), also known as von Willebrand’s or von Willebrand deficiency, is the most common bleeding disorder. It affects an estimated 1% of the population and is usually inherited, affecting men and women in equal numbers. Women living with VWD can have additional symptoms such as heavy menstrual blood loss and bleeding after childbirth.
Blood travels around the body through a network of blood vessels. Bleeding occurs when a blood vessel is damaged or injured. In an unaffected person, blood flows out of the vessel and blood platelets stick together to form a plug. A blood clot forms and acts like glue to repair the blood vessel and stop the bleeding. The clotting process, or coagulation, turns blood from a liquid to a solid state.
von Willebrand factor (VWF) is a blood protein that helps blood to clot. It helps the platelets to stick to the wall of the blood vessel to form a clot, and also acts a carrier of clotting factor VIII. In VWD there may be a shortage of VWF, or there may be something wrong with its structure so that it does not work properly. Sometimes there may also be a shortage of clotting factor VIII. This means that it takes longer for the blood to clot and for bleeding episodes to stop. A person with VWD will therefore have a tendency to bleed for longer than usual.
There are several types of VWD, which are defined by whether there is a shortage of VWF, or whether the VWF that is there does not work properly. It is important to know the type so that it can be treated and managed effectively. Although there is no cure for VWD, effective treatments are available.
People with VWD must not take aspirin in any form because it makes bleeding worse. Always read the label of any medicine package carefully and do not use the drug if it contains aspirin. If in doubt, ask a pharmacist.
Some medicines, such as warfarin, affect the clotting factors and are therefore not suitable for people with VWD. Other drugs, such as ibuprofen and non-steroidal anti-inflammatory medicines may need to be avoided. Paracetemol is safe for people with VWD, as it does not affect the way that platelets work. It is important to consult your centre before using any other medication or herbal remedies.
Types of Von Willebrand’s Disease
Type 1
This is the most common form of VWD, and means that the person has low levels of VWF, but the VWF that they have functions normally. Three out of every four people with VWD have Type 1. Bleeding is often classed as mild, which is difficult to define. Affected people may never have a serious bleeding problem, or they may find that they only bleed after an accident, childbirth or surgery. Type 1 is the most common type, accounting for an estimated 80% of cases of VWD.Type 2
This means that VWF is produced, but it does not work properly. Type 2 is divided into four subtypes: 2A, 2B, 2M and 2N.- Type 2A is the most common type. People affected have a large amount of VWF which does not work properly. Bleeding is classed as moderate.
- Type 2B is classed as moderate to severe and can be characterised by thrombocytopenia (low platelet count).
- Type 2M can cause mild to moderate bleeding episodes. It can be difficult to diagnose and is very like Type 1 VWD.
- Type 2N (also known as “Normandy”) is likened to haemophilia A as there are reduced levels of factor VIII. Bleeding is classed as mild to moderate, which could mean that the person may experience a bleeding pattern such as frequent nosebleeds and prolonged bleeding after an accident, childbirth or surgery.
