Von Willebrand's Disease
- Von Willebrand's disease is an inherited bleeding disorder that occurs most commonly in dogs and rarely in cats.
- It is caused by a deficiency in the quantity or activity of von Willebrand factor, a protein in the blood that helps platelets stick to injured surfaces to form a clot.
- It is found most commonly in Doberman pinschers, German shepherds, golden retrievers, poodles, and Shetland sheepdogs.
- Signs include prolonged bleeding after surgery or trauma, or bleeding from the nose, gums, and vagina, as well as bloody urine or feces.
- The disease can be diagnosed with a special blood test or with a DNA test.
- Treatment usually requires transfusions with blood or plasma products and/or administration of a synthetic hormone.
- There is no cure for von Willebrand's disease, and dogs with this condition should not be bred.
What Is Von Willebrand's Disease?
Von Willebrand's disease is the most common inherited bleeding disorder in humans and dogs. The disease rarely occurs in cats.
Dogs with this disease cannot clot blood normally, which results in bleeding, especially after surgery or trauma. While this disease has occurred in more than 50 different dog breeds, the breeds most commonly affected include Doberman pinschers, German shepherds, golden retrievers, poodles, and Shetland sheepdogs.
What Causes Von Willebrand's Disease?
The disease is caused by an inherited gene mutation that results in a deficiency in the quantity or activity of von Willebrand factor, a protein in the blood. When an animal is injured, cells called platelets stick to the damaged tissue to form a clot and prevent bleeding. Von Willebrand factor helps the platelets stick to each other, so a deficiency in this factor can result in abnormal bleeding.
What Are the Signs of This Disease?
Owners may not be aware that their dog has this disease until the pet experiences prolonged bleeding after a surgery or trauma. In severe cases, dogs may bleed from the nose, around the gum line, from the vagina, or have bloody urine or feces, even without trauma.
How Is This Disease Diagnosed?
Pet owners who have a breed with a high predisposition to the disease may want to test their dog as a puppy. A blood test can measure the amount of von Willebrand factor in the blood sample. A DNA test is also available for a small number of breeds and can be performed with a simple swab inside the mouth.
It is important to know if your dog has the disease so that your veterinarian can take the necessary precautions to control bleeding if your dog needs surgery or is injured. Dogs that have von Willebrand's disease or are carriers should not be bred, to prevent passing on the disease to their offspring.
In dogs suspected of having von Willebrand's disease, veterinarians can perform a screening test before surgery. Most commonly, veterinarians will check a buccal mucosal bleeding time. In this test, a small cut is made on the dog’s inner lip (sedation may be needed for some pets), and the length of time required for the bleeding to stop is measured. A prolonged bleeding time may indicate a bleeding disorder.
How Is Von Willebrand's Disease Treated?
There is no cure for von Willebrand's disease. However, in the event of a bleeding problem, dogs can be treated with transfusions of blood or plasma products to increase the amount of von Willebrand factor in the system. A synthetic hormone called desmopressin acetate may also be given to help the dog increase its level of von Willebrand factor.
It’s always better for the veterinarian to know about the disease before starting surgery. Transfusions may be given before, and if necessary, after the surgery to help prevent excessive bleeding. After treatment, the dog should be kept on strict cage rest and monitored until all bleeding has resolved.