Von Willebrand Disease
Von Willebrand disease (vWD) is an inherited bleeding disorder, similar to hemophilia, but the two disorders are not the same. vWD is the most common inherited clotting disorder, affecting both men and women. It's estimated that vWD affects up to one percent of the population. However, it is generally the least severe of the clotting disorders.
vWD is caused by a deficiency or defect of a blood clotting protein called von Willebrand factor (vWF), a gluelike protein that helps platelets in the blood stick together, forming a platelet plug and sealing off tears in injured blood vessels. If a person does not have enough vWF or it does not work properly, no platelet plug will form, and bleeding will continue for a longer period of time.
There are several types of vWD, but three major categories include:
- Type 1: The patient has a small amount of von Willebrand factor.
- Type 2: The patient has vWF, but is does not work correctly. Type 2 is further divided into four subcategories (A,B,M, N) depending on the type of defect.
- Type 3: There is no von Willebrand factor in the blood.
Blood testing can have varying results, so you may need to be tested several times before a diagnosis can be made. Pregnancy, stress, overactive thyroid disease, oral contraceptives, estrogen therapy, exercise and blood type AB can increase levels of vWF. Underactive thyroid disease and blood type O may lower the amount of vWF.
Most people with vWD will have few, if any, symptoms. The main symptoms are easy bruising, frequent or prolonged nosebleeds, heavy or prolonged menstrual bleeding and prolonged bleeding following injury, surgery, dental work or childbirth.
vWD is treated with desmopressin (also called DDAVP) or with infusions of a clotting factor concentrate that contains vWF.