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Von Willebrand disease





Von Willebrand disease is an inherited bleeding disorder. The disease is named after the doctor who discovered it, Erik von Willebrand. People born with the disease have one or both of the following:
  • Low levels of a protein called von Willebrand factor that helps the blood to clot
  • Von Willebrand factor that doesn't work properly
When von Willebrand factor is missing or doesn't work, it can cause prolonged bleeding after an injury or accident.


What is blood clotting?

An injury, like a cut, to a blood vessel causes a complex chain of events called the clotting process, which results in a blood clot. Blood clotting is your body's reaction to bleeding; it keeps you from losing too much blood. Losing too much blood can be life threatening and can damage your internal organs.


What is von Willebrand factor?

Von Willebrand factor is one of the proteins in your blood that helps it to clot. The cells that line the walls of your blood vessels (veins and arteries) make von Willebrand factor. When blood vessels are damaged, platelets (small blood cells that collect and stick together to plug cuts and breaks in blood vessels) clump together at the site of the injury. Von Willebrand factor acts like glue and helps the platelets stick together. Von Willebrand factor also carries and stabilizes clotting factor VIII, another protein that helps your blood to clot.


Outlook

Von Willebrand disease is a lifelong disorder. Most people with von Willebrand disease have a mild form of the disorder, which usually doesn't cause life-threatening bleeding and often doesn't require treatment. If treatment is needed, medicines and medical therapies are used.





Types of von Willebrand disease


Type 1

In type 1 von Willebrand disease, there is a low level of von Willebrand factor. The level of factor VIII may also be lower than normal. This is the mildest and most common form of the disease. About 3 out of 4 people diagnosed with von Willebrand disease have type 1.


Type 2

In type 2 von Willebrand disease, a defect in von Willebrand factor causes it to not work properly. Type 2 is divided into 2A, 2B, 2M, and 2N. Each is treated differently, so knowing the exact type is important.


Type 3

People with type 3 von Willebrand disease usually have no von Willebrand factor and very low factor VIII. Type 3 is severe and very rare.


What causes von Willebrand disease?

Von Willebrand disease is usually inherited – that is, passed in the genes from parent to child. Genes are located in the cells of the body and control how the cells make proteins, such as von Willebrand factor. Each cell in the body has two copies of every gene (except some genes related to gender). You inherit one copy from your mother and one from your father.

In a person with von Willebrand disease, one or both of the genes that control the production of von Willebrand factor are defective. Type 1 and type 2 von Willebrand disease can develop if a person inherits one copy of the defective gene from one parent and a normal copy of the gene from the other. Type 1 and type 2 von Willebrand disease also can develop if the person inherits a defective copy of the gene from both parents. Type 3 von Willebrand disease develops only if a person inherits a defective von Willebrand gene from both parents.

In rare cases, von Willebrand disease isn't inherited, but develops due to other reasons later in life. This is called acquired von Willebrand syndrome.


Who is at risk for von Willebrand disease?

Von Willebrand disease is the most common inherited bleeding disorder. It occurs in children who inherit one or two defective von Willebrand genes from their parents.

Mild defects in von Willebrand factor that occasionally cause bleeding occur in about 1 in every 100 to 1,000 people. Significant bleeding from von Willebrand disease occurs in about 1 in every 10,000 people. Unlike hemophilia, another inherited bleeding disorder that occurs mostly in males, von Willebrand disease occurs equally in males and females.


What are the signs and symptoms of von Willebrand disease?

The signs and symptoms depend on the type and severity of the disease. Some people have the gene for the disease but don't have bleeding symptoms.

People with type 1 and type 2 von Willebrand disease may have the following mild-to-moderate bleeding symptoms:
  • Easy bruising
  • Nosebleeds
  • Bleeding from the gums after a dental procedure
  • Heavy menstrual bleeding in women
  • Blood in their stools (from bleeding in the intestines or stomach)
  • Blood in their urine (from bleeding in the kidneys or bladder)
  • Excessive bleeding after a cut or other accident
  • Excessive bleeding after surgery
Heavy menstrual bleeding is the most common symptom in women who have von Willebrand disease. If untreated, it can lead to iron-deficiency anemia.

Doctors may test for von Willebrand disease in women who have unusually heavy menstrual bleeding. Some people may only be diagnosed after an episode of prolonged bleeding after an accident or surgery.

People with type 3 von Willebrand disease (rare and severe) are usually diagnosed in childhood. They may have:
  • Any of the symptoms listed above.
  • Severe bleeding episodes for no reason. These bleeding episodes can be life threatening if not treated immediately.
  • Bleeding into soft tissues or joints, causing severe pain and swelling. Bleeding into the joints is called hemarthrosis.

How is von Willebrand disease diagnosed?

Von Willebrand disease is sometimes difficult to diagnose. Mild symptoms may be mistaken for other illnesses. Severe von Willebrand disease can cause significant bleeding problems during infancy. Because of this, people with severe von Willebrand disease are usually diagnosed during the first year of life. People who have milder forms of the disease may not have significant bleeding problems, or they may have mild bleeding symptoms. People with milder forms of von Willebrand disease may not be diagnosed until adulthood.

Your doctor will review your personal and family history for signs and symptoms that indicate a bleeding disorder, including von Willebrand disease. Your doctor also may order laboratory tests.

If your doctor thinks that you have von Willebrand disease, specific tests must be done because some people with a mild form of the disease (type 1) may have normal results on the usual tests for bleeding disorders. If you have bleeding symptoms, your doctor will order blood tests that specifically check:
  • Your blood's ability to clot
  • The level of von Willebrand factor in your blood
  • How well the von Willebrand factor works (the "activity" of the factor)
These tests may be repeated several times to confirm the diagnosis.

Your doctor will order a combination of blood tests to diagnose the disease. These tests may include:
  • Von Willebrand factor antigen. This test measures the amount of von Willebrand factor in your blood.
  • Ristocetin cofactor activity. This test shows how well the von Willebrand factor works.
  • A test for factor VIII clotting activity. Some people with von Willebrand disease have low levels of factor VIII activity, while others have normal levels.
  • Von Willebrand factor multimers. This test is used to evaluate abnormal results of the tests listed above, and it shows the makeup or structure of the von Willebrand factor. This test helps your doctor diagnose what type of von Willebrand disease you have.
  • Platelet function test. This test measures how well your platelets and von Willebrand factor are working together.

How is von Willebrand disease treated?

Most cases of von Willebrand disease are mild and often don't require treatment. Treatment may only be needed to prevent or treat bleeding associated with surgery, tooth extraction, or an accident. For those who need treatment, one or more of the following may be used:
  • Medicine to increase the level of von Willebrand factor in the blood
  • Medicine to prevent the breakdown of clots
  • Medicine to control heavy menstrual bleeding in women
  • Injection of clotting factor concentrates (containing von Willebrand factor and factor VIII)
Your doctor will decide what treatment you need based on the severity and the type of disease you have. Specific treatments include:
  • Desmopressin (DDAVP), a synthetic hormone usually given by injection or nasal spray. DDAVP makes the body release stored von Willebrand factor into circulation, and it also increases the level of factor VIII activity. DDAVP is effective in treating most patients with type 1 von Willebrand disease and some patients with type 2A, 2M, or 2N von Willebrand disease. DDAVP can usually only be used two to four times for an individual bleeding episode because the body has a limited amount of stored von Willebrand factor.

  • Replacement therapy, which is the injection of a concentrated amount of von Willebrand factor and factor VIII into the body. This treatment can be used in:
    • People who can't take DDAVP or who need prolonged treatment
    • People with type 1 disease who don't respond to DDAVP
    • People with type 2A, 2B, 2M, or 2N disease
    • People with type 3 disease

  • Oral contraceptives (or birth control pills), which can help women who have heavy menstrual bleeding.

  • Antifibrinolytic drugs, which help prevent the breakdown of clots that form at bleeding sites. These drugs are used mostly to stop or prevent bleeding following minor surgery, tooth extraction, or an injury. They may be used alone or together with DDAVP or replacement therapy.

  • Fibrin glue, which is medicine placed directly on a wound to stop the bleeding.
Bleeding that can't be controlled can become life threatening. Rarely, people with severe forms of von Willebrand disease will need to seek immediate medical treatment to stop bleeding.


Living with von Willebrand disease

Preventing bleeding and staying healthy are important. If you have von Willebrand disease, you should:
  • Avoid over-the-counter medicines that can affect the clotting process, such as:
    • Aspirin and other medicines that contain salicylates
    • Ibuprofen and other nonsteriodal anti-inflammatory drugs

  • Tell your doctor or dentist that you have the disorder. You can receive medicine before dental work that will reduce bleeding. You may also want to tell your employee health nurse, gym trainer, or sports coach so they can alert medical personnel if you have an injury.

  • Always check with your doctor before taking any new medicines.

  • Consider wearing a medical ID bracelet or necklace if you have a serious form of von Willebrand disease (for example, type 3). You should also carry information in your wallet. If you have a serious injury or accident, the doctors caring for you will need to know about your condition.

  • Some safe exercises or activities are swimming, biking, and walking. Football, hockey, wrestling, and weightlifting (heavy weights) are not safe activities if you have had certain kinds of bleeding problems. Always check with your doctor before starting any exercise program.

  • If your child has von Willebrand disease that's severe enough to pose a significant risk of bleeding, your doctor may advise you to inform your child's caretakers or school personnel about the disease. For example, the school nurse, teacher, daycare provider, coach, or any leader of afterschool activities may need to know that your child has von Willebrand disease. This information will help them handle the situation if your child has an injury.

Related category

   • HEALTH AND DISEASE

Source: U.S. National Heart, Lung and Blood Institute