Overview Most basically, Von Willebrand's (abbreviated vWD) isn't so much a disease as a condition. Of all the inherited bleeding disorders in animals (and humans) it is the most common. The defect isn't autosomal (sex linked) so both males and females can suffer from the disease. It must be remembered that just because a dog doesn't show symptoms of von Willebrand's, it doesn't mean it can't be a carrier.
More specifically, von Willebrand's is an inherited bleeding disorder caused by lack of von Willebrand factor protein (abbreviated vWF). The vWF factor is a blood protein which binds platelets to blood vessels when they are injured. This protein circulates in the blood stream and must be present at the site of a blood vessel injury in order to control bleeding from that vessel. Absence or deficiency of the factor can, therefore, lead to uncontrolled bleeding episodes. Certain breeds have a higher incidence of vWD than others. German Shepherds, Doberman Pinschers, Shetland Sheepdogs, Chesapeake Bay Retrievers, German Shorthaired Pointers, Golden Retrievers, Standard Poodles and Scottish Terriers all have a higher than normal incidence, indicating that it can be inherited.
Dogs, without treatment, can bleed to death following surgery, or what might be normally considered less than life threatening injuries. If your dog has shown any bleeding tendencies in the past or there is known vWB in the dog's family it is best to notify your veterinarian before any surgery or procedure.
Symptoms Excessive bleeding is the main symptom. Bleeding generally occurs after a wound or surgery. In these cases, the blood simply does not clot in the normal time, and bleeding is extensive. The most common signs of vWD are spontaneous bleeding from the gums or nose, blood in the urine or gastrointestinal tract (which may cause the stool to either have blood in it, or be black and tarry), or excessive bleeding at the time of surgery. Bleeding into the joints may also occur, which can cause symptoms similar to those of arthritis. Other clinical signs include epistaxis, prolonged estrus or postpartum bleeding, hematuria, melena, excessive bleeding after toe-nail cutting and sometimes hemorrhaging into body cavities and organs.
Diagnosis The diagnosis of Von Willebrand's is made through a test which checks for the level of Von Willebrand's factor in the blood. To test a sample of a dog's DNA is taken, by gently wiping cheek swabs inside the dog's mouth, removing cells containing DNA. The swabs are then sent to a laboratory and tested for vWD. After testing the sample, the lab will send a summary of the results to your vet. The swipe from the cheek is a good sample because the cells that line the inside of a dog's cheek are continually being renewed, with new cells replacing the old ones. The cheek swab gently removes some of these old dead cells that contain perfect DNA samples for testing.
Diagnosis can be performed by measurement of plasma concentrations of vWF. TESTING SHOULD BE DONE AT AN EARLY AGE SINCE THE DISORDER OFTEN DIMINISHES WITH AGE, CAUSING FALSE-NEGATIVE TEST RESULTS IN OLDER ANIMALS. Additional screening tests such as bleeding times or platelet agglutination assays can also be performed.
Treatment Transfusions with blood collected from normal dogs is the only proven way to treat Von Willebrand's disease. Some dogs with Von Willebrand's disease also are hypothyroid - meaning they have lower than normal levels of thyroid hormone. Studies have shown low thyroid may raise the risk of bleeding complications in vVB dogs. Veterinarians have found that thyroid supplementation can lower the tendency in some dogs to bleed while raising the level of vWF concentration. Some studies have been done which suggest a drug called desmopressin acetate (DDAVP) may help dogs with a bleeding episode. The drug can be administered intranasally (into the nose) to increase clotting. There is still some controversy over whether this treatment is effective.
There is no cure for Von Willebrand's disease but there are some precautions an owner can take to reduce the risks to their dog. Avoid drugs that are known to inhibit platelet functions. Aspirin is a prime example of one of these drugs. Others include antihistamines, sulfa- or penicillin based antibiotics, Ibuprofen, the tranquilizer phenothiazine, heparin and theophylline. Prevention through eliminating affected individuals from any breeding program is the goal of veterinary medicine today. Tests are available to determine which dogs may have this trait. All individuals with a history of this disorder in their backgrounds should be tested.
Von Willebrand's disease isn't an automatic death sentence to dogs. Many of the dogs that have the condition will live normal lives with no complications. For those that do show clinical signs, there are usually options for the owner to guarantee the best quality of life the pet can have.
Summary GSDs in general have a vWF classification of 1 which gives them a tendancy to have low concentrations of vWF. The structure of vWF protien is usually normal and clinicial severity is variable.