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. (Factor VIII is the protein that is missing or defective when someone has hemophilia.)
In people with VWD, the Von Willebrand factor clotting protein is missing 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 lead normal, active lives.
The symptoms of Von Willebrand disease can include:
- having a lot of nosebleeds
- easy bruising that happens a lot
- 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
- long-lasting or a lot of bleeding after circumcision
- 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 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 very rarely can happen after birth. The child of a man or a woman with VWD has a 50% chance of getting the gene.
- In types 1 and 2, a child can inherit the gene for the disease from one parent only.
- In type 3, the child usually needs to inherit the gene from both parents. In those cases, the child will likely have severe symptoms, even if the parents have no symptoms.
A child also can inherit the gene and show no symptoms, but as a carrier 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 its ability to function
- 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 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 may not be helpful in treating Type 2A or Type 2B.
People with Type 3 (and some with Type 2A and 2B) will need treatment with Humate-P, an intravenous medicine derived from human plasma that contains factor VIII and Von Willebrand factor. Those with Type 1 also might receive Humate-P in some situations, such as major trauma or major surgery, although they usually can be treated with desmopressin.
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?
- Contact sports are risky for kids and teens with VWD. Instead, they could stay active with activities like swimming, biking, and walking.
- 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.
- Male infants with a family history of VWD should not be circumcised without a doctor's OK.
- Girls with VWD who have started their periods might want to take extra pads or a change of clothes in case of accidents.
- 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.
Call your doctor right away if your child has any excessive or unexplained bleeding.