Von Willebrand's disease

By Brandon Brooks, DVM
Copyright 1999, Brandon Brooks. Used with permission.

Von Willebrand's Disease (vWD) is both an inherited and acquired condition. Breeds most commonly inheriting the trait for this disease are Doberman Pinschers, standard poodles, Pembroke Welsh Corgis, Scotties, Shelties and golden retrievers, among others. This disease, which is a deficiency in a certain clotting factor (a blood protein), can also be caused by other conditions such as hypothyroidism, estrus, pregnancy, infections and certain drugs including NSAIDs like aspirin.

vWD is the most common inherited bleeding disorder in dogs, and it is a recessive trait that can affect males and females equally. These dogs lack the ability to manufacture von Willebrand's factor, or Factor VIII (8), a blood protein essential in the clotting cascade. With its absence, blood cannot clot properly and many affected animals will spontaneously bleed. Without the ability to clot reliably, these animals are at serious risk of bleeding to death.

Sometimes problems are noted first when the animal bleeds spontaneously, such as a nosebleed. vWD can also be picked up during things like a nail trim, and if one of the nails is "quicked" it doesn't stop bleeding, even with much application of styptic powder. It can also be noticed at the time of spaying or neutering, or during examination when blood is drawn for a heartworm test. Bleeding can also be noted in vomitus or in the stool, and the presence of a dark tarry stool indicates bleeding in the upper GI tract.

Other clotting problems can cause these signs, so just because a commonly affected breed is bleeding like this doesn't mean it's vWD, so a workup is always in order and this usually entails general bloodwork as well as specific clotting function tests and testing of thyroid function.

In emergent situations, patients with vWD will need one or possibly more blood transfusions, depending on the severity of the condition and when diagnosed. Dogs with vWD should have limited activity levels, eat soft food only, not get intramuscular injections, not have neck leads and should never be on certain antibiotics or NSAIDs like aspirin.

If an underlying condition exists that is causing the vWD (the acquired form), then it should be treated to improve their status. For the inherited form and when a cause cannot be found, a medication does exist to help enable the patient to make more von Willebrand's factor, but each animal's response is different. All vWD patients should be monitored closely over time for any signs of bleeding.