Von Willebrand’s Disease, or vWD, is the most common inherited blood clotting disorder in both dogs and humans. It is the result of a deficiency in the amount of a specific protein needed to help platelets stick together and form clots. This protein is called von Willebrand Factor (vWF). The condition can lead to excessive bleeding following an injury, even mild cuts, due to the inability of the blood to clot.
The hereditary disorder occurs with more frequency in some breeds, including German Shepherds, Doberman Pinschers, Standard Poodles, Shetland Sheepdogs, and Golden Retrievers. However, Doberman Pinschers seem to be the breed with the highest incidence of vWD.
VWF is a non-sex-linked trait which is expressed in and transmitted by both males and females with equal frequency. The expression pattern can come in one of several types which may affect certain breeds in various frequencies.
Type 1 vWD is the mildest form of the disease while Types 2 and 3 are the more severe forms. Chesapeake Bay Retrievers and Scottish Terriers are more likely to be afflicted with one of these types than other breeds.
Symptoms of von Willebrand’s Disease in Dogs
Many dogs with vWD will not outwardly display symptoms unless injured. However, some may experience the following symptoms:
- Spontaneous hemorrhage from mucosal surfaces including:
- Blood in feces, either black or bright red in color
- Blood in urine
- Bleeding gums
- Excessive vaginal bleeding in females
- Easily bruised skin
- Prolonged bleeding after surgery or trauma
If there is prolonged bleeding, your dog may develop anemia as a result of the blood loss. Death is possible for those dogs that experience uncontrollable bleeding.
Diagnosis of vWD in Dogs
A clinical diagnosis of von Willebrand Disease is possible with a blood test conducted by your veterinarian. The screening test, called the Buccal Mucosal Bleeding Time (BMBT) test, measures the length of time that it takes platelets to clot a small injury.
Prolonged bleeding as a result of this test will raise suspicions of the disease, especially in those breeds known to have a higher risk. To confirm the diagnosis, the exact amount of von Willebrand Factor present in the blood can be determined through a very accurate laboratory blood test.
Prolonged bleeding after a surgical sterilization procedure, spaying, or neutering may be the first time an abnormality is noticed though the disease may go undetected for a number of years.
Treatment for von Willebrand’s Disease in Dogs
Many dogs with a mild to moderate vWD diagnosis will continue to have a good quality of life, requiring minimal or no special treatment. Those with severe cases, however, can be maintained comfortably but their activities will need to be monitored and limited. In the event of an emergency, these dogs would need to receive transfusions of fresh whole blood, fresh plasma, fresh frozen plasma, or cryoprecipitate to supply the blood with von Willebrand Factor.
The dog donating the blood may be treated with a drug called DDAVP, generically known as desmopressin acetate, prior to collection, which will raise the level of vWF in the blood, an obvious benefit to the dog with von Willebrand Disease.
Some dogs with vWD may also respond to treatment with DDAVP in an effort to increase the presence of von Willebrand Factor in their own blood. However, response is variable so regular use of the drug is not currently recommended by most veterinarians. Your vet may discuss this treatment option with you and help you decide if it is an appropriate option for your pet’s condition.
The avoidance of certain medications is also critical for dogs with vWD. Drugs which may increase the likelihood of a bleeding crisis in the dog include:
- Sulfa-based antibiotics
- Phenothiazine tranquilizers
Some research also shows that stress or anxiety in dogs may exacerbate or precipitate spontaneous bleeding episodes. Those owners with vWD diagnosed pets should try to maintain a stress-free lifestyle. You will want to closely monitor your pet for bruising or bleeding if you travel, have houseguests, or other stressful events occur in the dog’s life.