Von Willebrand Disease
Von Willebrand disease is the most common inherited bleeding condition. The cause is a deficiency in or impairment of a protein called von Willebrand factor, which is an important component in the blood clotting process. In general, it takes longer for people with von Willebrand disease to form clots and stop bleeding when they're cut.
Treatment of von Willebrand disease focuses on stopping or preventing bleeding episodes, typically by using medications that increase the levels and activity of von Willebrand clotting factor and related substances in your blood. Von Willebrand disease affects males and females in approximately equal proportions and is present in up to 1 percent of the U.S. population.
Von Willebrand disease was first identified in the 1920s by Erik Adolf von Willebrand, a Finnish doctor. He noted its presence in people in the Aland Islands, located in the Baltic Sea between Finland and Sweden.
The cause of von Willebrand disease is a defect in the gene that controls von Willebrand factor. When this factor is scarce — or not functioning properly because of structural abnormalities — small blood cells called platelets cannot stick together normally and attach themselves to the vessel walls when an injury has occurred. The result is interference with the clotting process, and uncontrolled bleeding persists.
A family history of von Willebrand disease is the leading risk factor. A parent can pass the abnormal gene for the disease to his or her child. Most cases are "autosomal dominant inherited" disorders, and if you have the gene for von Willebrand disease, you have a 50 percent chance of transmitting this gene to your offspring. To inherit the most severe form of the condition (type 3), both of your parents have to pass along the gene to you.
Race does not appear to play a role in the disease, except
|that affected women who have extended and heavy menstrual bleeding are more likely to be Caucasian rather than African-American.
When to seek medical advice:
Contact your doctor if you're experiencing extended or severe bleeding.
If you're scheduled to have surgery (including dental procedures), make sure your doctor or dentist knows that you have von Willebrand disease, which can increase the likelihood of post-surgical bleeding.
Consider wearing a medical ID bracelet, noting that you have von Willebrand disease, in case you're in an accident and are taken to an emergency room.
In many people with von Willebrand disease (vWD), signs are mild or they may be absent altogether. When signs occur, their intensity can vary from one person to another. In its milder forms, von Willebrand disease is often missed by doctors in the diagnostic process.
Abnormal bleeding is the most common symptom of von Willebrand disease, although it may be present at only moderate levels. The abnormal bleeding may occur as:
People with von Willebrand disease may also experience easy bruising and skin rashes.
- Recurrent and prolonged nosebleeds
- Bleeding from the gums
- Increased menstrual flow
- Excessive bleeding from a cut or following a tooth extraction or other dental procedure
- Blood in the stool or urine
Women affected by von Willebrand disease may not be overly concerned by a moderate or even heavy level of increased menstrual bleeding. And doctors may overlook heavy menstrual bleeding as a possible indicator of von Willebrand disease.
Some people may realize that they have a bleeding disorder only after a surgical procedure or serious trauma in which excessive bleeding occurs.
Classifications of the disease
There are three major classifications of von Willebrand disease:
- Type 1. Signs may be mild in type 1, the most common form, and tend to occur in people with only modest declines in the blood levels of both von Willebrand factor and factor VIII, a substance that's carried in your blood by von Willebrand factor and that helps stimulate clotting.
- Type 2. In this type, which has several subtypes, signs tend to be more intense. In these people, the von Willebrand factor that is present doesn't function properly.
- Type 3. People with type 3 disease, which is rare, lack von Willebrand factor altogether and have low levels of factor VIII. Bleeding may occur into the joints and muscles, and signs and symptoms may be severe in intensity.
Because many people with von Willebrand disease have very mild signs, the condition can be difficult to diagnose. Some people live for years with the disease before it's identified.
Your doctor will likely begin by taking a complete medical history and asking whether your parents or siblings have had bleeding problems. He or she will also ask specifically about any abnormal bleeding that you've had, including a history of symptoms such as easy bruising or childhood nosebleeds. Your doctor will also want to know how often these bleeding episodes occur, the circumstances in which they start, and how long they last.
If you have any indication of a bleeding disorder, your doctor may refer you to a specialist in blood disorders (hematologist), who may perform specific blood tests to diagnose or rule out von Willebrand disease. These tests may be repeated to confirm that the diagnosis of von Willebrand disease is correct, and to determine the disease type. The results of these tests can fluctuate in the same person over time, due to factors such as stress, excessive exercise, blood transfusions, recent surgery and pregnancy.
To help make the diagnosis, doctors choose from among blood tests that measure:
The results of some of these tests may not be available for two to three weeks after blood is drawn because they need to be conducted in a specialized laboratory. When these findings are analyzed together, your doctor can make a definite diagnosis. If von Willebrand disease is present, your doctor may recommend that family members undergo the same tests to determine if this condition runs in your family.
- Von Willebrand factor (vWF) antigen. This test determines the level of von Willebrand factor in your blood by measuring the vWF protein (antigen).
- Ristocetin cofactor activity. This analysis of your blood demonstrates the functional activity of von Willebrand factor in the clotting process. Ristocetin, which is an antibiotic, is used in this laboratory testing and when added to a sample of your blood, causes a reaction in your blood that may indicate von Willebrand disease.
- Factor VIII clotting activity. This test shows whether you have abnormally low levels and activity of factor VIII carried by von Willebrand factor.
- von Willebrand factor multimers. This test evaluates the specific structure of von Willebrand factor in your blood, its protein complexes (multimers) and how its molecules break down. This information helps identify the type of von Willebrand disease that's present.
- Platelet aggregation. This test measures how efficiently platelets are functioning in your blood.
- Bleeding time. This test indicates the time needed for bleeding from a small cut to stop.
Complications of von Willebrand disease may include:
- Anemia. Women who experience heavy menstrual bleeding can develop iron deficiency anemia.
- Swelling and pain. If abnormal bleeding flows into the joints or soft tissue, swelling and severe pain can result.
- Death from bleeding. When abnormal bleeding cannot be controlled, it can become life-threatening and needs emergency medical attention.
Even though von Willebrand disease is a lifelong condition with no cure, your doctor can treat it effectively. Treatment may vary, depending on the type and severity of the disorder, as well as your response to previous therapy and other medications you may be taking. The most commonly used treatments for von Willebrand disease include the following:
If your condition is mild, your doctor might recommend treatment only when you're undergoing surgery or dental extractions, or when you've experienced trauma (in an automobile accident, for example).
- Desmopressin (DDAVP). This medication is administered by injection into a vein or under your skin, or more commonly through a nasal spray called Stimate. It's a synthetic hormone similar to the natural hormone vasopressin that controls bleeding by stimulating your body to release more von Willebrand factor already stored in the lining of your blood vessels — thereby enhancing factor VIII levels. DDAVP is usually effective in people with type 1 and some subtypes of type 2 disease. Many doctors consider it the first treatment to use in the management of von Willebrand disease. Some women use the nasal spray at the beginning of their menstrual periods to control excessive bleeding. You can also use it before a minor surgical procedure.
- Replacement therapies. These consist of infusions of prepared doses of concentrated blood clotting factors containing von Willebrand factor and factor VIII. They can be useful in all disease types, and your doctor may recommend them if DDAVP isn't effective or particularly if you need treatment for more severe forms of the disease.
- Oral contraceptives. These can be useful for controlling heavy bleeding during your menstrual periods. The estrogen hormones present in birth control pills can boost levels of von Willebrand factor and factor VIII activity.
- Antifibrinolytic or clot-stabilizing medications. These medications, such as aminocaproic acid (Amicar) and tranexamic acid (Cyklokapron), can slow down the breakdown of clotting factors. This can help keep a clot in place once it has formed, putting a stop to bleeding. These drugs are available as tablets or intravenously. Doctors often prescribe them before or after a surgical procedure or tooth extraction.
- Fibrin sealants. These substances, applied like a glue using syringes, are placed directly on a cut to curtail bleeding.
To help prevent bleeding episodes, don't take blood-thinning medications, such as aspirin, ibuprofen (Advil, Motrin, others) or other nonsteroidal anti-inflammatory drugs (NSAIDs), without the approval of your doctor. Your doctor may recommend pain relievers such as acetaminophen (Tylenol, others) instead for routine aches and pains and for fever. Your doctor may also advise you to avoid prescription blood thinners such as warfarin (Coumadin) and heparin.
Because von Willebrand disease is an inherited disorder, consider having genetic counseling if you're planning to have children. If you carry the defective gene for this condition, you can pass it on to your offspring, even if you don't have symptoms.
|Please be aware that this information is provided to supplement the care provided by your physician. It is neither intended nor implied to be a substitute for professional medical advice. CALL YOUR HEALTHCARE PROVIDER IMMEDIATELY IF YOU THINK YOU MAY HAVE A MEDICAL EMERGENCY. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with any questions you may have regarding a medical condition.