Von Willebrand's Factor. How To Understand What It Is, and What To Do About It.

Greta.
Looking a bit perplexed.

Greta is a six month old blue Doberman puppy. She was purchased by an older couple who wanted a doberman. Seems simple enough? BUT, there are so many things pet parents need to know before you go jumping into a life long relationship. 

Here's what her parents didn't know;

1. Dobermans are most common breed at risk for the most common inherited bleeding disorder in dogs, Von Willebrand's disease. They had never heard of this disease.

2. Greta has no paperwork. Therefore, we have no idea what her parents Von Willebrands status was? Were they ever tested? What were their results? Have any of Greta's siblings been tested, or had a bleeding disorder? History is such an important and over looked part of every case.

3. Without knowing the answers to number 2 her vet opted to address her spay as cautious as possible. So, Dr. Morgan called the referral hospital to inquire about having Greta spayed there? They quoted over $1,000 to do it. (At our clinic it is about $250). Big difference! Yes, her parents thought so too, and decided to forego the referral.

With a limited budget, a scant history, and her parents desire to have her spayed Dr. Morgan did her due diligence to fill in some of the blanks and help her parents make a safe, educated decision about how to proceed with Greta's elective surgery.

What an adorable face.

Here's what Dr. Morgan did:

1. Performed a through physical examination.

2. Based on Greta's dilute color, (she is what we call 'blue' an the perceived and tested links between autosomal recessive traits and incidence of disease) she performed a Von Willebrand's assay the week before her spay was scheduled.

3. Called for a consult about how to prepare for her surgery.

4. Gave Greta's parents lots of options and then helped them decide which were best for them.

Von Willebrand's disease is inherited. Dogs affected get it from their parents. Both males and females can have the disease or pass it along to offspring. The disorder occurs because of a deficiency or disorder of von Willebrand factor (vWF). Von Willebrand's factor is a plasma protein essential for the platelets in the blood to allow a clot to form and stop bleeding. If you have a breed commonly affected, like the Doberman pinscher, Scottish terrier, Shetland sheepdog, golden retriever, Pembroke Welsh Corgi, or standard poodle it is wise to suspect vWF if they ever have abnormal bleeding events. This can include nail trims, trauma, or problems with surgeries.

Greta's Von Willebrand's assay results were 22 (low).

• The normal values for canines are 70-180% (weird I know you can get a better score than 100%, but yes, you can). 
• 50-69% is considered "borderline normal" (reassuring isn't it? How do you interpret that when the lab notes it as " indeterminate range"
• <50 % abnormal carrier for vWF:AG

To make the testing more confusing, many experts will add that many dogs in the <20% range never show any signs of bleeding abnormalities. They also will tell you that the level of the vWF does not always correspond to the likelihood that they will bleed. OK, a little reassuring if you have a dog with say <20 %, but isn't the opposite true? Yes, you can have a dog previously tested and found to be "normal" who bleeds uncontrollably and life-threateningly. Terrific!

Good Girl!

DDAVP  (desmopressin) can be used pre-operatively (before surgery, just in case you do have a bleeding problem, you need to have this in the patient BEFORE surgery) as a prophylaxis. BUT it is not effective for severe Type 2 or 3 Von Willebrand dogs. (YIKES!! so confusing!) BUT, desmopressin is not commonly used in veterinary general practice clinics and it is very expensive. SO, when you mention it to a client, that MIGHT, or MIGHT NOT need it, OR MIGHT OR MIGHT NOT even benefit from it, it is a tough call. SO, there you are back at square one. Not really knowing what to advise OR what to do.

For Greta's spay her family opted to have her spayed with Dr. Morgan. Dr Morgan placed an i.v. catheter, paid very close attention to minimizing tissue trauma and maintained a high degree of surgical precision to minimize bleeding. IF the patients don't bleed significantly they don't need as many clotting factors. There are many cases of vWF pets doing very well under the most traumatic accidents and surgeries. For vWF pets they should have a physical exam, buccal mucosal bleeding time (BMBT), and careful precision in surgery. If the BMBT is abnormal they should be pre-treated with DDAVP and have fresh frozen plasma standing by should bleeding become a concern.

 

Thankfully, Greta had no surgical concerns or complications. But her family knows that any future surgeries need to be met with care and concern and any traumatic events monitored very closely.

I spoke to Dr. Morgan about Greta's case and we corroborated each others previous experiences with having doberman's with this disease, and the prevalence of seeing vWF positive dogs who are dilute blue's. If you have one of the breeds mentioned, or a dog with a dilute blue/silver coat thinking about this disease might be prudent to help avoid a medical emergency down the bumpy road of life. 

Dr. Morgan has a blue Cane Corso. He was tested, based on her color superstition and found 'normal' but has bled abnormally with each knee surgery he has had. 

That's disease for you, does what it wants and leaves you guessing in spite of 'being an expert."

Dr. Morgan and her boy, Cletus.
Recovering after his cruciate repair surgery.

If you have a question about this, or any other pet related item, you can find me chatting away, helping other people with their pets at Pawbly.com, or on Twitter @FreePetAdvice.