Mar 1 2008
The National Heart, Lung, and Blood Institute (NHLBI) of the National Institutes of Health, has issued the first clinical guidelines in the United States for the diagnosis and management of von Willebrand Disease (VWD), the most common inherited bleeding disorder.
The guidelines include recommendations on screening, diagnosis, disease management, and directions for future research. An extensive article on the guidelines is published online Feb. 29 in the journal Haemophilia.
In VWD, low or absent levels of a blood protein called von Willebrand factor affect the blood's ability to clot. Von Willebrand factor also carries with it clotting factor VIII, another important protein that helps blood clot. VWD is typically milder but more common than another bleeding disorder, hemophilia. However, for some people with VWD, the condition can pose serious health risks, especially during surgery, following an injury, or during childbirth. VWD affects 1 out of every 100 to 1,000 people - both males and females. Hemophilia mainly affects males.
“These are the first guidelines on von Willebrand Disease published in the United States and we are pleased to offer clinicians science-based recommendations in the evaluation and treatment of patients,” said NHLBI Director Elizabeth G. Nabel, M.D. “The disease can be difficult to diagnose, especially in women of child-bearing age and in children, and the danger of excessive bleeding is often under-recognized.”
In consultation with the American Society of Hematology, the NHLBI convened an expert panel on VWD whose members were selected for their scientific and clinical knowledge and experience, including specialists in hematology as well as family medicine, obstetrics and gynecology, pediatrics, internal medicine, and laboratory sciences. A draft of the guidelines was posted on the NHLBI Website for a 30-day public comment period in September 2006.
Screening recommendations in the guidelines call for physicians to take a complete medical history and physical examination, and order a sequence of blood tests to evaluate persons whose history suggests VWD or any bleeding disorder.
The symptoms of VWD include frequent large bruises from minor bumps or injuries, frequent or hard-to-stop nosebleeds, extended bleeding from the gums after a dental procedure, heavy bleeding after a cut or after surgery, and heavy or extended menstrual bleeding in women. “The guidelines provide physicians with recommendations for diagnosing and treating the three major types of VWD,” said William L. Nichols, Jr., M.D., associate professor of medicine at the Mayo Clinic in Rochester, Minn., and chairman of the NHLBI expert panel that developed the guidelines. “While von Willebrand Disease cannot be cured, it can be treated. Proper diagnosis is important, and with the right treatment plan, even people with type 3 VWD, the most serious form, can live active lives.”
The guidelines address the three types of von Willebrand disease.
- In type 1 VWD, patients have a low level of the von Willebrand factor, and may have lower than normal levels of factor VIII. This is the mildest and most common form of VWD. About three out of every four people with VWD have type 1 VWD.
- In type 2 VWD, the von Willebrand factor does not work the way it's supposed to. Type 2 VWD is divided into subtypes 2A, 2B, 2M, and 2N. Each type is caused by different gene mutations and treated differently.
- In type 3 VWD, patients usually have no von Willebrand factor and low levels of factor VIII. Type 3 is the most serious form of VWD, but is very rare.
People with type 1 or type 2 VWD may not have major bleeding problems, according to Nichols, and, as a result, they may not be diagnosed until they have heavy bleeding after surgery or some other trauma. On the other hand, type 3 VWD can cause major bleeding problems during infancy and childhood. As a result, children with type 3 VWD are usually diagnosed during their first year of life.
Since heavy menstrual bleeding is the most common symptom of VWD in women, the guidelines suggest that a full gynecological exam be performed before diagnosis of VWD is made. In addition, the guidelines address the challenges that pregnancy and childbirth present for women with VWD.
“Even before conception, VWD patients should consult with a hematologist and an obstetrician who specializes in high-risk pregnancies,” said Andra James, M.D., assistant professor of obstetrics and gynecology in the Division of Maternal-Fetal Medicine at Duke University and a member of the NHLBI expert panel. “Once pregnant, women with VWD should consider using a center that specializes in high-risk pregnancies.”
Treatment for VWD depends on its type and severity and this makes knowing the exact type of VWD a patient has very important. Most cases of VWD are mild, and may require treatment only for surgery, tooth extraction, or injury. Medicines may be prescribed to replace von Willebrand factor, or increase the release of it into the bloodstream (desmopressin), to prevent the breakdown of clots (antifibrinolytics) or to control heavy menstrual bleeding in women (oral contraceptives).
According to the guidelines, it is important for people with VWD to avoid over-the-counter medicines that can affect blood clotting, including aspirin, ibuprofen, and other nonsteroidal anti-inflammatory drugs (NSAIDs). Those with VWD should talk to their dentist to determine if medicine is needed before dental work to reduce bleeding. Anyone over two years of age with VWD should be immunized against hepatitis A and B to decrease risks of complications from blood transfusions. It is important to exercise regularly and maintain a healthy weight. Safe exercises include swimming, biking, and walking. Football, hockey, wrestling and lifting heavy weights are not recommended for people with VWD.
The NHLBI von Willebrand Disease Expert Panel was established in spring 2004 in response to a recommendation from the FY 2004 Congressional appropriations conference committee. The committee urged NHLBI to work with medical associations and experts in the field to develop a set of treatment guidelines for VWD.