von Willebrand disease

Overview

Von Willebrand Disease (vWD) is a bleeding disorder that slows down the blood clotting process, which can lead to excessive bleeding after injury, surgery or dental work along with nosebleeds, easy bruising and heavy menstrual periods. Children with vWD almost always inherit the disease, as it is the most common of all inherited bleeding disorders (one in every 100 to 1,000 children are born with vWD). Usually, the bleeding symptoms in vWD are milder than hemophilia.

Children born with von Willebrand Disease (vWD) either have low levels of a certain protein in their blood (called von Willebrand factor or vWF ) or make vWF protein is not working the way it should. This factor plays two important roles in blood clotting. The glue-like protein is found in cells that line the blood vessel walls and in platelets, as well as in blood, and helps platelets stick to blood vessels that have been cut or torn from injury. It also binds to one of the other clotting factors (factor VIII) to protect it from degradation. Blood clots protect the body by preventing blood loss and sealing off damaged blood vessels. People with vWD can experience prolonged bleeding because their blood clots slowly.

Signs & symptoms

Von Willebrand Disease (vWD) is usually inherited, meaning the disorder is passed from the child's parents through genes. Unlike hemophilia that almost always affects only boys, vWD affects boys and girls equally. Symptoms include frequent bruising, excessive bleeding after a pulled tooth and bleeding in the muscous membranes, such as nose and gums.

There are three forms of vWD — type 1, 2 and 3 — and the symptoms vary depending on the type and severity of the disease.

Type 1: This is the most common and mildest form of the disease, where levels of von Willebrand factor (vWF) are slightly lower than normal. Children with this type don't usually spontaneously bleed, but may have significant bleeding with surgery or serious injury.

Type 2: This type, which is divided into several subtypes, is where the vWF is not working properly. The vWF can be defective in its ability to bind platelets, the blood vessel lining, or factor VIII to stick together or the factor's ability to stick to the platelets is increased.

Type 3: This is the most severe form, where the body produces very little, if any, vWF and there are very low levels of clotting factor VIII. This form can cause severe bleeding problems and is very rare.

Diagnosis

The diagnosis of von Willebrand Disease (vWD) is based upon the combined information from the patient's symptoms, the family history, and blood tests. Tests that can help diagnose vWD include one that measures the amount of von Willebrand factor (vWF) in the blood; a test that measures the vWF activity levels; a test for factor VIII levels; a test to look at the structure of the vWF; and a platelet functions test. In addition, your child's family history will be discussed, as well as the child's experiences with injuries, nose bleeds, bruising and dental trauma.

Treatment

Treatment for von Willebrand Disease is tailored to the severity of the disease and to the type of injury or procedure that a patient with the disease might experience. Medications, including the synthetic hormone Desmopressin, may be given to temporally raise levels of von Willebrand factor (vWF) and factor VIII in the blood steam to reduce the potential of bleeding. Other therapies include those that prevent the breakdown of blood clots, and replacing vWF with an infusion of vWF and factor VIII intravenously.