Von Willebrand Disease
What Is Von Willebrand Disease?
Von Willebrand disease, or VWD, is a genetic (inherited) bleeding disorder that prevents blood from clotting properly. Bleeding disorders (including hemophilia) are rare. Von Willebrand disease is the most common bleeding disorder, and affects males and females equally.
What Happens in Von Willebrand Disease?
Normally, when a blood vessel is cut or torn, bleeding stops because of the blood's ability to clot (to plug the hole in the blood vessel and stop the flow of blood). This complex process involves platelets and proteins called clotting factors.
Von Willebrand factor is involved in the early stages of blood clotting, and also carries the important clotting protein factor VIII. In people with VWD, the amount of Von Willebrand factor clotting protein in the blood is lower than normal or doesn't work as it should.
What Are the Signs & Symptoms of Von Willebrand Disease?
Many kids with VWD have such mild symptoms that they never know they have it. Those with a more severe form of the disease, though, need proper diagnosis and a treatment plan to help them reduce bleeding symptoms.
Symptoms of Von Willebrand disease can include:
- having a lot of nosebleeds
- easy bruising that happens a lot
- in girls, heavy, long-lasting periods
- long-lasting or a lot of bleeding during and after procedures (a tooth extraction, tonsillectomy, etc.)
- cuts that ooze blood for longer than usual
- bleeding in the mucous membranes, such as the gums, nose, and lining of the gastrointestinal system
What Are the Types of Von Willebrand Disease?
There are various forms of VWD:
- In Type 1, the level of Von Willebrand factor in the blood is reduced and the level of factor VIII also might be reduced. This is the most common and mildest form of the disease. The symptoms might be so minor that the person isn't ever diagnosed. People with type I VWD usually do not bleed spontaneously but can have a lot of bleeding with menstrual periods, trauma, surgery, or when they have a tooth pulled.
- In Type 2, the level of Von Willebrand factor in the blood is normal, but doesn't work as it should. Type 2 has several subtypes, including:
- Type 2A: The building blocks that make up the factor (called multimers) are smaller than usual or break down too easily.
- Type 2B: The factor sticks to the platelets too well, leading to clumping of the platelets, which can cause a low platelet number.
- In Type 3, Von Willebrand factor and factor VIII levels are very low or missing. Symptoms are severe and may include bleeding into joints and muscles.
- Pseudo, or platelet-type, Von Willebrand disease is similar to type 2B, but the defect is in the platelets instead of in the factor.
What Causes Von Willebrand Disease?
Like hemophilia, VWD is a genetic disorder. Usually, it's passed from parent to child, but sometimes can happen after birth. The child of a man or a woman with VWD has a 50% chance of getting the gene.
A child also can inherit the gene and show no symptoms, but still can pass the gene on to any offspring.
How Is Von Willebrand Disease Diagnosed?
Because symptoms can be mild, VWD can be hard to diagnose and often isn't found.
Blood tests used to diagnose VWD include:
- Von Willebrand factor antigen test, which measures the amount of Von Willebrand factor
- Von Willebrand activity test (also called ristocetin cofactor or RCF activity test), which measures how well the Von Willebrand factor works
- factor VIII activity test (also called factor VIII coagulant assay), which measures the level of factor VIII and how it's working
- Von Willebrand multimers test, which helps to classify the type of Von Willebrand disease
- platelet function tests, which see how well the platelets work
Tests might need to be repeated because the levels they detect may rise and fall over time. Also, the doctor will take a family medical history to see if other relatives have a bleeding disorder.
How Is Von Willebrand Disease Treated?
The most common treatment for VWD is desmopressin. This synthetic (manmade) hormone causes a temporary increase in the Von Willebrand factor and factor VIII levels. It can be given as an injection or a nasal spray. But it doesn't work for everyone and may not be helpful in treating type 2. Some patients will need treatment with an intravenous (IV, given into a vein) form of Von Willebrand factor.
Medicine to slow or prevent the breakdown of blood clots also might be used, and fibrin glue can be put directly on a wound to stop bleeding.
What Else Should I Know?
- If bleeding happens, apply pressure to the area.
- During nosebleeds, pinch the soft part of the nose and have your child lean slightly forward to keep the blood from flowing down the throat.
- Tell your child's hematologist if any surgery or procedures are planned.
- Male infants with a family history of VWD should not be circumcised without a doctor's OK.
- Girls with VWD who are having very heavy or long-lasting periods may want to see an adolescent medicine doctor or a gynecologist for advice.
- Tell the dentist that your child has VWD. Your child might need medicine before dental work to reduce bleeding.
- Kids with VWD should not take aspirin and other non-steroidal anti-inflammatory drugs (NSAIDs), such as ibuprofen, for pain or fever. These drugs affect how platelets work and can increase the risk of bleeding. It is safe to take acetaminophen, which doesn't affect platelet function.
- Contact sports might risky for kids and teens with VWD. Instead, they could stay active with activities like swimming, biking, and walking. Discuss any restrictions with your doctor.
- Call your doctor right away if your child has any excessive or unexplained bleeding.