This is a blood clotting disorder, the most common bleeding disorder in dogs (and in man). Severe spontaneous bleeds such as occur with haemophilia are quite rare with von Willebrands. Affected animals may have longer than normal seasons, with more bleeding than normal; they may haemorrhage following even minor surgical procedures (or whelping), or even bleed to death; they may bleed from mucus membranes such as in the mouth or have nose bleeds; they may develop frequent haematoma or bruising, or have swellings appear under the skin; they may pass blood in faeces or urine; they may have recurrent diarrhoea with or without bleeding; they may have dry, flaking skin, particularly in the ears; excessive bleeding from the umbilicus cut at birth, from dew claw removal, docking, or having toe nails cut too short; they may die under anaesthesia, as the disease predisposes to such deaths.
However, not all affected dogs will actually bleed, or they may do so only sometimes during their life and not always. And von Willebrands status can alter during an animal's life and a previous non-bleeder can become a bleeder, or the percentage of the von Willebrands Factor in the blood can be raised by such events as seasons and pregnancies so that an older animal may show a higher reading than might have been the case as a youngster.
An underlying but hidden bleeding tendency (an apparent non-bleeder) can be exacerbated by stress such as illness, particularly viral disease since any viral infection can prolong clotting times by impairing platelet and/or endothelial cell production. Live virus vaccines have the same effect.
It is inherited in all breeds (apart from the Scottish Terrier and Chesapeake Bay Retriever) as an autosomal dominant with incomplete penetrance, which in simple terms means that it is passed on direct from one generation to the next, it is not sex-linked, and occurs in varying degrees in affected animals. Any dog found to have the condition has to have at least one affected parent and will itself pass it on to some of its progeny. The likelihood is that the progeny will be affected to a greater extent than the parent.
Unlike haemophilia, VWD affects both sexes. Dogs having the condition will not necessarily be clinically affected (but will still pass it on to their progeny) and those which are will be affected to varying degrees. Homozygotes (animals which receive the gene from both parents) will usually die either in utero or soon after birth, as this is a lethal genetic effect.
Von Willebrands in both parents can therefore lead to smaller than average litters, stillbirths (particularly macerated puppies), or "fading puppies".
In the Scottish Terrier and Chesapeake Bay Retriever the condition is inherited either as an autosomal dominant with incomplete penetrance or as a recessive, the latter meaning that it can only occur when both parents were either affected or carriers; the genes for the disorder have to come from both parents.
However, VWD can be secondary to hypothyroid (underactive thyroid), rather than a primary disorder. In these cases, treating the underlying hypothyroid will remove the VWD.
Because of the nature of the gene causing VWD, normal tests for blood clotting cannot be used, as an affected animal can have normal blood clotting times. Von Willebrands status can be determined only by having a blood sample tested for von Willebrands Factor Antigen (VWFAg). The result is given as a percentage.
There is an overlap between affected and normal ranges, which has been taken into account in the suggested breeding procedures. "Normal" is between 60 and 172 per cent but 60-69 per cent is suspect and animals in this range should be bred only to mates testing over 70 per cent, and all the puppies tested.
If any of the puppies test at under 50 per cent, then the parent with the low normal rating is a carrier and breeding from known carriers should be strictly limited. This line can be continued by using a puppy which has tested over 70 per cent.
Seven per cent is the level at which VWFAg is undetectable and animals testing thus are severely affected. Any animal testing under 50 per cent is either a carrier or clinically affected. Clinically affected animals should never be bred from.
Puppies can be tested as soon as they are weaned and large enough for blood to be obtained from their veins. Bitches should not be tested within two weeks of a season, when in whelp, or for two months following whelping. Dogs should not be tested within ten days of vaccination, as vaccines can affect test results. If a dog is receiving medication when tested, the type of medication and the dosage rate should be specified when sending in the blood sample.
Management during the period of taking the blood sample is very important and can affect the results to a marked degree. The animal should not be fed for several hours before the sample is taken, and the sample needs to be got to the testing laboratory as quickly as possible and the tests performed immediately.
If your dog is found to have VWD, what can you do about it? A lot depends on whether or not he/she is clinically affected (a bleeder), although it is undoubtedly safer to work on the assumption that any animal testing under 50 per cent could be a bleeder and manage it accordingly. Certainly the percentage of VWFAg is not a clear indication of whether and how much an animal will bleed. For example one with 15 per cent did not bleed, whereas one with 47 per cent did. It would be sensible to have any dog testing positive for VWD tested for hypothyroid (which see).
Certain drugs should be avoided in treatment of dogs with VWD as they interfere with haemostasis (blood clotting) and thus exacerbate any tendency to prolonged clotting times. Such drugs include aspirin, phenylbutazone, promozine-derivative tranquillizers, oestrogens, introfurans, sulfonamides, anti-inflammatory drugs such as cortisone, penicillin compounds, local anaesthetics, phenothiazines, and plasma expenders such as dextran and HES.
The problem with live virus vaccines is greatest during the period of five to ten days after vaccination, so if an affected dog has to have necessary surgery, vaccination with live virus vaccines should preferably not be carried out, or should be done well away from the surgery date.
If a dog testing under 50 per cent VWFAg has to have surgery, but it is not known if he/she has a bleeding tendency, the suggestion is that as soon as the dog has been anaesthetised one toe nail be cut too short with ordinary guillotine clippers and the clotting time noted. If the bleeding stops within five or six minutes, then the dog is unlikely to have a serious bleeding problem following surgery, although the test does not preclude the existence of a slight haemostatic defect. Clinically affected dogs will bleed for longer and may even not stop bleeding until cauterised.
It should be borne in mind that VWD predisposes to death under anaesthesia quite apart from any haemorrhaging that may occur, so unnecessary surgery is best avoided.
Clinically affected dogs will require plasma or possibly a blood transfusion. Dogs with bleeding problems may well require repeated blood transfusions during their lives so are at risk from transfusion incompatabilities. Use of unmatched whole blood is contraindicated unless in a life-threatening emergency.
The correct treatment would be to give fresh, typed universal donor blood at a dosage of 3.5 ml per pound of bodyweight. Otherwise, fresh-frozen homologous plasma at 2.5 ml per pound body weight twice daily. If a dog is known to be clinically affected it should be given 3.5 ml per pound bodyweight of fresh, compatible whole blood two to four hours before surgery.
VonWillebrands Disease is known in wolfhounds in America and Great Britain to my knowledge. However, the tests available (at least in England) have given conflicting results in a few cases, which has meant that very few breeders in England actually test their breeding stock even though the conflict was said to be due to the way in which the blood samples were taken or that the hounds had been fed shortly before the blood sample was taken.
|This is Kore. She had VWD with a score of 15, although she was not a
bleeder. She also had epileptiform fits.
Knowing what I know now, I would have had her thyroid tested at Hemopet but at the time I was not aware of all that.
Most of the snake venoms cause haemorrhaging, so the homoeopathic Crotalus Horridus (rattlesnake venom) in a high potency such as 10M would be a useful emergency remedy for severe bleeds. For dogs which get the more minor bleeding symptoms such as oozing from mucal surfaces, then Arnica or Hamamelis would be useful remedies, depending on the symptom picture.
OAK would be the most suitable of the Bach Flower Remedies to give to an affected dog.
|Article on Symptoms and Treatment of Canine Von Willebrands Disease on the Petwave website|
|Article on Von Willebrands Disease on the healthypets.mercola.com website|
|The Veterinary Medical Clinic page on Von Willebrands Disease|
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Hypothyroid is the most common of the thyroid dysfunctions and it is reckoned by some experts in the field that it occurs in some 47 per cent of all dogs. Hypothyroid is where the thyroid does not produce enough thyroid hormone, but symptoms of hypothyroid can occur in dogs in which the thyroid is working normally but the adrenals are not, as a lack of the adrenal hormone cortisol can limit the uptake of the thyroid hormone. This means that there is plenty of thyroid hormone around but the cells cannot utilise it. Read "Pet Allergies: Remedies For An Epidemic" by Alfred J. Plechner, DVM for full details on adrenal insufficiency and how it can affect the thyroid. One of the major causes of hypothyroid in dogs is auto-immune thyroiditis, a disorder in which the immune system attacks the thyroid. Adrenal insufficiency is also implicated in immune-mediated disorders.
The symptom picture associated with hypothyroid in most peoples' minds is overweight, lethargy, hair loss bilaterally (on both sides of the body), usually starting on the loin area, and hair becoming dry and brittle. However, this picture is not even the most common. Hypothyroid can lead to weight loss and hyperactivity. It is also probably the major cause of aggression and mood swings.
Other symptoms can include problems with seasons (of any kind - too long, too heavy, too long between, too short a period between, starting either too early or not starting until very late in life; complete absence of seasons; silent heats); false pregnancies; infertility; stillborn pups; pups that are weak or dying at birth; atrophy of the testicles; skin disorders of many kinds, including chronic offensive odour; cruciate ligament damage; frequent pulled muscles/strained tendons; cardiac arrhythmias; cardiomyopathy; constipation; diarrhoea; vomiting; megaoesophagous; paralysis of the larynx and face; drooping eyelids; head tilt; knuckling over or dragging feet; weakness and stiffness; muscle wasting; corneal ulceration; "dry-eye" and other eye disorders; chronic infections; behavioural/temperament problems.
In the U.K. the tests available for thyroid function are poor and really only show up gross malfunction such as myxoedema (a condition in which the thyroid function is almost or completely non-existent and the gland becomes atrophied).
Hyperthyroid is a condition in which the thyroid is producing too much hormone. This can lead to weight loss, palpitations, overheating, racing heart and is usually due to a tumour of the thyroid. This condition is quite rare in dogs but common in cats.
The Bach Flower Remedy OLIVE plus the constitutional remedy (possibly AGRIMONY or OAK); the homeopathic remedies IODUM or THYROIDINUM, plus the constitutional remedy. See also under Nutritional Therapy. Deficiencies of iodine and selenium cause hypothyroid.
|Detailed article on hypothyroidism in dogs on the healthypets.mercola.com website|
|Article entitled Behavioral Changes Associated with Thyroid Dysfunction in Dogs by W. Jean Dodds, DVM and Linda P. Aronson, DVM|
|Canine Hypothyroidism by David Bruyette United States on the WSAVA website|
|Very detailed article - with pictures of many symptoms - on hypothyroidism on the Long Beach Animal Hospital website|