What Do I Need To Know About Thyroid Before Going To The Vet?

[Guest feathersprings]

For the last few weeks Draco has been losing lots of coat on his legs, belly, sides and is now extending to his neck where it is getting thin. His coat has been flaky since he came to me a few months ago. At first I thought it was probably stress. He is a shy boy but adapted fairly easily to my husband and I ( with us he is a big goofy clown!). I cant say he is lethargic ( any more so than our other Grey) I made him an appointment with the vet for Thursday and have been reading some about thyroid problems. The level numbers are confusing to me but will probably print out some info for my vet before I go. Any suggestions to insure I get a proper diagnosis?? Also, anyone have info about shyness and thyroid??? I have read this a few times and never knew there might be a correlation . Draco is quite shy and even with my son who visited for several weeks would not warm up to someone new. He REALLY wants to be more social and will "sneak" up from behind but if someone sees him he runs

 

 

[Burpdog]

How long off the track?

 

You need to do a thyroid panel, but not before he's been off the track for 6 months

[Greytlady94]

Draco's shyness sounds pretty normal for a newly adopted greyhound. Remember that his whole life as he knew it has changed. As for his losing his coat it is typical for them to blow their coat when they come off the track or farm. Taking him to the vet is a good thing to do, that way the vet can give him a thorough exam.

[Guest smarthound]

Greyhound blood values are different from other dogs. Is your vet greyhound savvy?

 

You can search "Greyhound Blood Values" on this board for a pinned posting of Dr. Stack's analysis. You can take a copy to your vet when you go.

[Guest greytexplorer]

Here's an old thread that has some interesting info about thyroid:

 

http://forum.greytalk.com/index.php?showto...&hl=thyroid

 

If you want to print it out and take to your vet:

click on OPTIONS button (located just above "Post #1")

click on Print This Topic in the dropdown menu

 

 

You also might want to enter "Dr Couto" in the search box and see what you get. Good luck!

[ahicks51]

"Normal" values for a grey can be close to the detection limits of the labs performing the test- there's simply not enough precision. IDEXX and the other commercial lab (I forget the name) perform almost all of the lab tests for veterinary purposes.

 

However, Michigan State (which used to do the test by dialysis) and Hemopet in California *may* have certain advantages over traditional testing if it is required. The MSU lab also has a veterinary endocrinologist who, for a small fee (about $5) will offer a professional interpretation based on sighthound figures as to the recommended course of action, if any is required. Dr. Dodds at Hemopet will do the same thing, and I think it's already included in the lab fee. She knows greyhounds very well.

 

if MSU is back to doing the test by dialysis, then I'd suggest going with MSU.

 

The problem with both labs is that if your vet doesn't use them already, it'll be up to you to submit the sample. Vet does the draw and spins the sample down, then you take the sample and mail (Priority Mail, box-in-a-box to prevent crushing, no ice required- unless things have changed) along with a check for the lab fees. They fax the results to your vet.

 

But! I agree with the others- the coat, the flaky skin, etc. are characteristic of a dog fresh off the track. Wait 6 months, feed fish oil capsules if you like, and re-assess then whether testing is required.

[feemandvm]

Share these abstracts with your vet. Also... send the sample to Michigan State's lab and request an interpretation. Personally I would avoid Hemopet.

 

 

Thyroid Function Testing in Greyhounds

Sm Anim Clin Endocrinol 12[1]:4 Jan-Apr'02 Review Article 0 Refs

C.B. Chastain, DVM, MS, Dipl. ACVIM (Editor) & Dave Panciera, DVM, MS, Dipl. ACVIM (Assoc. Editor) Sm An Clin Endo

Gaughan KR, Bruyette DS.; Am J Vet Res 2001; 62:1130-1133

BACKGROUND: Thyroid function tests are frequently evaluated in greyhounds because of alopecia, infertility, and poor race performance. In most cases, hypothyroidism is not present, despite the finding of decreased serum total thyroxine (T4) concentrations. Sight hounds, including greyhounds and Scottish deerhounds are known to have serum T4 concentrations lower than other breeds of dogs. This can result in an erroneous diagnosis of hypothyroidism.

SUMMARY: Basal serum T4, free T4 (fT4), and the serum T4 and fT4 response to thyroid-stimulating hormone (TSH) administration were evaluated in a group of healthy pet dogs and in two groups of healthy greyhounds. All pet dogs and 56 greyhounds had serum T4 and fT4 response to thyrotropin-releasing hormone (TRH) administration evaluated. Serum concentration of endogenous canine TSH (cTSH) was measured in 18 pet dogs and 87 greyhounds. The pet dog group consisted of 19 dogs of various breeds (no greyhounds), with a mean age of 5.2 years. One group of greyhounds consisted of 37 female dogs with a mean age of 1.4 years that were actively racing and currently receiving testosterone for suppression of estrus. The second group of greyhounds consisted of 61 dogs with a mean age of 4.9 years that were not receiving testosterone. Greyhounds receiving testosterone were significantly younger than those not receiving testosterone and pet dogs. Of the greyhounds not receiving testosterone, none of the females (n = 35) were racing, while 10 of the 26 males were actively racing. No dog had received thyroid supplementation, glucocorticoids, or anabolic steroids with the exception of testosterone within 3 months of study. The mean basal serum T4 concentration was significantly lower in the greyhound groups than in the pet dog group. The mean basal serum fT4 concentration was significantly lower in the greyhound groups than in the pet dog group. The mean serum T4 response to TSH was significantly greater in pet dogs than in greyhounds either receiving testosterone or not. Greyhounds receiving testosterone had significantly higher serum T4 concentrations post-TSH than greyhounds not receiving testosterone. While there was no difference between the mean serum fT4 concentration after TSH administration in pet dogs and greyhounds receiving testosterone, the fT4 concentration in greyhounds not treated with testosterone was significantly less than the other groups. The mean serum T4 concentration in response to TRH administration was significantly lower in both groups of greyhounds than in pet dogs. The mean serum fT4 concentration after TRH administration was significantly lower in greyhounds not receiving testosterone than in greyhounds treated with testosterone or pet dogs. Mean serum cTSH concentrations were not significantly different between any of the three groups. The reference ranges for all greyhounds were established as basal concentrations of T4, fT4, and cTSH were 2.1 to 37 nmol/L, 1.3 to 32.2 pmol/L, and 0.03 to 1.3 ng/ml, respectively. The authors concluded that greyhounds have a lower reference range for serum T4 and fT4 concentrations than that of other breeds.

CLINICAL IMPACT: This study shows that serum T4 and fT4 concentrations in greyhounds are considerably lower than in non-greyhound dogs and clearly demonstrates the difficulty in diagnosing hypothyroidism in this breed. The lower limit of the reference range for T4 and fT4 concentrations in greyhounds is near the lower sensitivity of the assays. Therefore, it may be impossible to establish a diagnosis of hypothyroidism based solely on these hormones. Because the serum TSH concentration was similar to that of other breeds, an elevated cTSH combined with T4 and fT4 concentrations at the low end of the reference range combined with appropriate clinical signs is necessary to diagnose hypothyroidism in greyhounds. Dynamic testing using TSH or TRH stimulation testing may also be useful, but less practical. Testing when appropriate clinical signs are present is of particular importance in greyhounds. Caudal thigh alopecia, common in greyhounds, is not caused by hypothyroidism, and infertility is likely to be only infrequently caused by hypothyroidism in female dogs. Exogenous testosterone used to suppress the estrous cycle does not appear to alter basal serum concentrations of T4, fT4, or c-TSH, but responses to TSH or TRH stimulation may be increased by testosterone administration.

 

Thyroid function testing in Greyhounds.

Am J Vet Res 62[7]:1130-3 2001 Jul

Gaughan KR, Bruyette DS

OBJECTIVE: To evaluate thyroid function in healthy Greyhounds, compared with healthy non-Greyhound pet dogs, and to establish appropriate reference range values for Greyhounds.

ANIMALS: 98 clinically normal Greyhounds and 19 clinically normal non-Greyhounds.

PROCEDURES: Greyhounds were in 2 groups as follows: those receiving testosterone for estrus suppression (T-group Greyhounds) and those not receiving estrus suppressive medication (NT-group Greyhounds). Serum thyroxine (T4) and free thyroxine (fT4) concentrations were determined before and after administration of thyroid-stimulating hormone (TSH) and thyroid-releasing hormone (TRH). Basal serum canine thyroid stimulating hormone (cTSH) concentrations were determined on available stored sera.

RESULTS: Basal serum T4 and fT4 concentrations were significantly lower in Greyhounds than in non-Greyhounds. Serum T4 concentrations after TSH and TRH administration were significantly lower in Greyhounds than in non-Greyhounds. Serum fT4 concentrations after TSH and TRH administration were significantly lower in NT-group than T-group Greyhounds and non-Greyhounds. Mean cTSH concentrations were not different between Greyhounds and non-Greyhounds.

CONCLUSIONS AND CLINICAL RELEVANCE: Previously established canine reference range values for basal serum T4 and fT4 may not be appropriate for use in Greyhounds. Greyhound-specific reference range values for basal serum T4 and fT4 concentrations should be applied when evaluating thyroid function in Greyhounds. Basal cTSH concentrations in Greyhounds are similar to non-Greyhound pet dogs.