This is for advice to Puppy Buyers and will be completed over time.
Topics will include;
Is this the right breed for you?
What are the Health concerns you need to know about in Samoyeds?
How to Choose and Handle a Vet
Idiots Guide to Hip Scoring
Grooming for your Pet
To Neuter or Not to Neuter
Drugs and Samoyeds
Questions to ask a Samoyed Breeder
How to Test for Thyroid Problems
Autoimmune Hypothyroiditis (AH) is the most common thyroid disease in dogs covering 90% of Hypothyroid cases. Hypothyroid is used to describe the condition that occurs when the Thyroid Gland is not mobilizing iodine and producing hormones, T3 and T4. These in turn are used to stimulate hormone production for the rest of the body. Lack of it can affect many functions in the body.
A.H occurs when antibodies in the blood or tissue start to attack the Thyroid gland, thus affecting the amount of T3 and T4 produced. Why they attack is still the source of mystery, but there is a genetic element involved is some breeds. Research is still ongoing in Samoyeds but researchers suggest that up to 50 breeds of dog may suffer from this condition.
Signs and Symptoms
Actual signs of the disease don't start to appear until more when 75% of the Thyroid gland has been destroyed by antibodies. Because the Thyroid is an important master gland, if it doesn't work, it can affect multiple organs, from the skin to fertility. Classic signs are alopecia (hair loss), greasy regrowth of hair especially on the body and the 'rat tail'; lethargy, easy weight gain, not liking exercise. Also fast heart rate and sometimes severe neurological signs occur, with Ataxia (uncoordination), circling, aggression. Infertility in male and females also occurs.
Please note hypothyroid dogs tend to develop hyperkalemia (elevated potassium) during exercise; this is due to the fact that certain trace elements cannot be stored in the muscle in hypothyroid dogs so they end to suffer from muscle weakness; a bit like the effect of the 'pain barrier' on marathon runners.
How is Autoimmune Hypothyroiditis diagnosed?
Diagnosing A.H has changed over the last few years. Initially, the T4 and TSH used to be used for diagnosis. Then Free T4 was added to the list. These can determine if the dog is functionally hypothyroid but do not indicate if the dog has the autoimmune version.
It is suggested that any dogs that have only had these tests and declared clear should be tested under the newer protocols and the following tested.:
This last test is particularly revealing as these are the antibodies that destroy the Thyroid.
If the Thyroglobulin Autoantibody (TgAA) levels are elevated but the T4 levels still relatively normal it means that the AH is confirmed but there is still enough functioning Thyroid to produce the T4 and FT4.
It is even possible that an affected dog has no obvious clinical symptoms.
But these tests have to be repeated as the dog gets older. The TSH level goes down when there is no Thyroid left to be stimulated. Likewise, the TgAA goes down when there is no Thyroid left for the antibodies to attack.
It really is a slippery slope interpreting these results and I would urge a referral to a Vet with experienced in Endocrinology if you encounter this disorder. I would also urge you not to self medicate. This is complicated stuff and with the best will in the world, you could prematurely ruin what is left of your pet's thyroid system with misdiagnosis or incorrect dosing.
There are other things that can cause abnormal thyroid test results. For instance, there is a condition called Sick Euthyroid. This is illustrated by a decreased T4 but all other values being normal. The T4 alone can be decreased for various reasons; toxins are one, but more likely is the adverse effect of medication.
. Glucocorticoids: high dosages, chronic therapy: T4 falls, FT4D more resistant, TSH is unchanged or decreased
Sulfonamides: chronic therapy may cause reversible hypothyroidism
Phenobarbital: chronic therapy - mild fall in T4 and FT4D; TSH remains normal in most dogs, but rises in a small percentage.
Carprofen: TT4 mild fall, FT4D normal
Clomipramine: mild fall in TT4 and FT4D; TSH remains normal
It is important that current medication is taken into consideration when any dog is being diagnosed for any disorder, but Thyroid levels seem to be very prone to deviation.
Causes
Most affected breeds are now thought to have a genetic component. It appears to be polygenic (has a number of different genes involved). It has been suggested that nutrition and toxins may trigger a genetically susceptible animal.
Treatment Guidelines
There is very good medication available which can control the disorder for many years. Soloxene (I think this is Soloxine unless the UK version is something different) is the drug of choice for most clinicians; it is given once a day and doseage is dependent on the weight of the dog. Another TgAA (TgAA??) test should be done after a fortnight to check the correct doseage is being given.
Where the affected animal has shown clinical obesity on diagnosis, weight should start to drop off as a result of medication. He or she should be reweighed regularly to make sure you are not overdosing.
Breeding advice
I recently took advice from Dr Jeff Sampson at the Kennel Club on this and he strongly advises against affected bitches being bred from.
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I have an extensive list of references for this article should anyone require them. A more extensive article can be seen on www.Samoyedhealthfoundation.org where it has been audited by a professional.
And why am I suddenly interested in this disease, you may ask. The answer is that I have a bitch that I couldn't get in whelp and when she did 'take' she re-absorbed. This was her only clinical sign.
The work that Brian Catchpole is doing about Diabetes ties in with Thyroiditis; an 'allele is also associated with hypothyroidism, suggesting that this could represent a common susceptibility allele for canine immune-mediated endocrinopathies.' Quote.
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Hazel Fitzgibbon
November 6, 2008