Von Willebrand’s Disease in Dogs

The most common inherited bleeding disorder in people and dogs is von Willebrand’s disease.  DNA testing is currently available for certain breeds through a company called VetGen.

There are three types of von Willebrand’s disease in dogs.  In Type I, all the proteins are present but only in very small amounts.  This is the type common in the Doberman Pinscher, ShetlandVon Willebrand’s Disease in Dogs Sheepdog, German Shepherd, and Standard Poodle.  In Type II, the larger proteins making up von Willebrand’s factor are completely absent, leaving only the smaller proteins.  This creates

Dogs Von Willebrand’s Disease

Gorgeous example of German Short Haired Pointer, courtesy of http://marysbeagooddogblog.blogspot.com/2010/04/sweetest-german-shorthair.html

more severe bleeding episodes and represents the type of von Willebrand’s disease usually seen in German Short-Haired and Wire-Haired Pointers.  In Type III, there is simply no von Willebrand’s factor at all.  This is the most severe form and is seen in Scottish Terriers, Chesapeake Bay Retrievers, and Shetland Sheepdogs.

Normally, von Willebrand’s factor is produced by platelets and endothelial cells which line blood vessels.  When there is damage to a blood vessel wall, von Willebrand’s factor causes platelets to adhere to the wall and form a primary hemostatic plug.  In dogs that have von Willebrand’s disease they typically do not bleed spontaneously.  They often bleed excessively when they have surgery, such as a neuter or ovariohysterectomy (“spay”).  The bleeding can be substantial and can require blood transfusions to prevent the dog from bleeding to death.

Diagnosis of von Willebrand’s disease

The diagnosis of von Willebrand’s disease requires measuring the von Willebrand factor in the dog’s blood and comparing it to a normal dog.   A normal von Willebrand’s factor level is generally between 70-180%, borderline is 50-69%, and abnormal is less then 49%.  Other blood coagulation testing should be normal, such as the prothrombin time, partial thromboplastin time, and platelet count.  The time to get results for the von Willebrand’s factor test is typically a few days.  If a veterinarian is suspicious a dog has von Willebrand’s disease another screening test they can perform is a buccal mucosal bleeding time.  This is a simple test to check the dog’s primary hemostasis function.  If the test is normal the likelihood of von Willebrand’s disease is very low.  If the test is positive, there are multiple potential causes, such as von Willebrand’s disease, low platelet count, or platelet dysfunction.

Treatment for von Willebrand’s disease

If the diagnosis of von Willebrand’s disease is confirmed the dog should be treated prior to having any surgery, or procedure that might cause bleeding.  The most effective treatments are cryoprecipitate, or plasma, which contains von Willebrand’s factor.  These are blood products that should be given shortly before the surgical procedure to avoid excessive bleeding.  This will improve the bleeding time for approximately 4 hours.  Another treatment for von Willebrand’s disease is DDAVP (desmopressin acetate) which can increase the release of von Willebrand’s factor in the dog’s body for about 2 hours.  This treatment has a variable response and might not be a sufficient pre-operative treatment.  Dog’s with von Willebrand’s disease can live a full life and typically only have problems when surgery causes excessive bleeding.

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Dr Peter Nurre

Peter Nurre, DVM, Diplomate ACVIM (internal medicine) is a board- certified veterinary internal medicine specialist. His professional interests include internal medicine and cardiology.

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