Very Low Thyroid Levels

[LadyGrey]

I had a full profile of blood work done on Sophie. My vet just called me at my office to say that her thyroid levels are so low they are immeasurable. He will give her Levothyroxine where I will administer 2 tablets per day. Everything else in her blood work looks perfect. I will talk to him after work today.

 

Has anyone else had any experience with hypothyroid levels so low?

 

I appreciate it.

[MP_the4pack]

Dr Couto just gave a talk about that at GIG. I approached him about it because my vet did ask for the TSH test as follow up and it was high. He said for me to mail him the results and he would determine if my girl is hypothyroid.

So the minimum for you to do is get a TSH (Thyroid Stimulating Hormone). Greyhounds are notorious for very low T4 and still have a normal functioning thyroid.

If you also have that result, send them to Dr. Couto.

[LadyGrey]

Thanks so much.

[NeylasMom]

Do not medicate without a full panel from MSU, end of story. If it were my dog and there were no symptoms, physical or behavioral, I might not even bother with that, but just wait and see what the level was on the next blood panel so long as nothing else changed. But the more responsible thing to do is probably to follow through with the panel, or at least a TSH as mentioned.

[Neighsayer]

No advice, but no problem viewing your post. Good luck!

[macoduck]

From Dr Stack's website www.greythealth.com :

 

T4

greyhounds .5 - 3.6

other dogs 1.52 - 3.60

 

If clinical signs of hypothyroid are present, consider testing T4 with cTSH.

 

What is the dosage your vet is suggesting ?

Edited May 8, 2014 by macoduck

[greysmom]

I would be skeptical of medicating for low thyroid in a greyhound in the absence of any other clinical signs. The thyroid test usually done by vets can be affected by many different things, including the time of day, when they last ate, some medications can suppress or enhance a reading.

 

One of mine had a reading of 0.2 - which is very low. But he had no other clinical symptoms, and was actually getting too much thyroid when he was supplemented.

[greyhead]

I agree that you should have a full panel done. Disagree that MSU has to do it.

[seeh2o]

I agree that you should have a full panel done. Disagree that MSU has to do it.

 

I agree with all of what greyhead wrote.

[JJNg]

Here's a good article you may want to print out for your vet. There's a good chance Sophie isn't really hypothyroid.

 

http://www.vet.ohio-state.edu/assets/pdf/hospital/bloodBank/wellness/newsletters/2010/ghwpNewsletterWinter2010.pdf

[greyhead]

With all due respect, Michigan State is not the only lab that includes TSH in its profile. Perhaps that sentence in the Ohio State piece is outdated.

[LadyGrey]

Hello and thank you everyone for the replies. I actually left the vet without getting a copy of her readings. Arrrggg.

 

He prescribed 0.6 mg of Levothyroxine to be administered twice per day.

 

She had a physical exam and a general senior profile. He said he did a TSH on Sophie although it is not specifically listed on the bill. I will get a copy of her readings today.

Edited May 9, 2014 by LadyGrey

[GeorgeofNE]

Dr. Couto has said he has NEVER seen a truly low thyroid Greyhound.

[greyhead]

And yet they've existed.

[seeh2o]

Dr. Couto has said he has NEVER seen a truly low thyroid Greyhound.

I've heard him say that, too, in person. Carl wasn't in the room with me at the time, so I guess he's right. If he had been, he'd have to change the statement.

[tbhounds]

I've heard him say that, too, in person. Carl wasn't in the room with me at the time, so I guess he's right. If he had been, he'd have to change the statement.

Actually he said he has seen 4 truly hypoT ghs and 2 of them had their thyroid gland(s) excised (one of those hounds was my girl Shannon-- she had classic signs of hypoT post surgery--her cholesterol was sky high as was her cTSH -it was just under 5-ref Idexx labs ). I think the point of posting that statement is it's extremely rare to find a hypoT hound and further bloodwork is recommended before starting supplementation.

[Guest grey_dreams]

It's beyond understanding that some believe that there is at least one organic life form on Earth that has evolved THE PERFECT ORGAN that can NEVER EVER EVER fail. I mean really, can you imagine? Every aspect of every organism on Earth can become diseased and fail, every pathway, every tissue, every organ.

 

There is a simple problem with the antibody that is routinely used for running the TSH tests. The antibody was raised against TSH protein from another organism (IIRC, it was human TSH). Protein sequences and tertiary structures differ from one organism to another, and sometimes those differences are enormous. Antibodies are raised with specificity for protein tertiary structure. If the protein tertiary structures are very different from one organism to the next, then antibody analysis won't give accurate results. The TSH antibody that they use to run the tests on dogs is not specific for greyhound TSH. That's why vets (and now most of the population) are quite content with baseline values of 0.00-.0.02. But by routinely accepting the fact that the antibody is nonspecific and doesn't recognize greyhound TSH with high accuracy (and adjusting expectations for baseline values accordingly), some greyhounds that do have low TSH are falling through the net.

[tbhounds]

AND this is why clinical signs as well as other blood work values (ie: cholesterol) are so important when evaluating your hound. Of course are there hypoT hounds not being diagnosed -sure. It's the thousands of hounds on supplementation without need that is just as concerning.

[NeylasMom]

It's beyond understanding that some believe that there is at least one organic life form on Earth that has evolved THE PERFECT ORGAN that can NEVER EVER EVER fail. I mean really, can you imagine? Every aspect of every organism on Earth can become diseased and fail, every pathway, every tissue, every organ.

 

There is a simple problem with the antibody that is routinely used for running the TSH tests. The antibody was raised against TSH protein from another organism (IIRC, it was human TSH). Protein sequences and tertiary structures differ from one organism to another, and sometimes those differences are enormous. Antibodies are raised with specificity for protein tertiary structure. If the protein tertiary structures are very different from one organism to the next, then antibody analysis won't give accurate results. The TSH antibody that they use to run the tests on dogs is not specific for greyhound TSH. That's why vets (and now most of the population) are quite content with baseline values of 0.00-.0.02. But by routinely accepting the fact that the antibody is nonspecific and doesn't recognize greyhound TSH with high accuracy (and adjusting expectations for baseline values accordingly), some greyhounds that do have low TSH are falling through the net.

Do you mean T4? It's TSH that tends to run high in hypothyroid dogs and the range you're referencing for greyhounds is for T4.

[greyhead]

If I could take a stab at it, Jen, since grey_dreams doesn't seem to be around just now...

People/vets have accepted T4 values of 0.0 - 0.2 as normal in greyhounds because the dogs appear normal from the outside and have low TSH values. If, however, the TSH values were high (and, I always add, if the dogs could actually tell us how they felt), then we'd define that level of T4 as too low. But we've accepted the non-specificity and low accuracy of the antibody to greyhound TSH, so we've accepted those low T4 values as normal for greyhounds. Thus, some hypothyroidism in greyhounds is missed. If I understood correctly.

[Burpdog]

The TSH test is not as accurate in dogs as it is in humans.

 

In a senior dog, a low T4 can be a sign of a sick thyroid, however, at some point you need to make a choice about quality of life.

 

when a dog has a very low T4 and is sleeping 22 hours a day, there is a need for thyroid meds espcially in a senior. I would not medicate a younger dog without the thryoid panel. I am sure there are other places that do a panel, but MSU is very affordable and I bet much cheaper than other labs.

[RaineysMom]

Dr. Couto has said he has NEVER seen a truly low thyroid Greyhound.

yes, he has. When I sent him our Rainey's results (with the full TSH) he told me she was the fourth greyhound he's ever seen that was truly low thyroid.

Actually he said he has seen 4 truly hypoT ghs and 2 of them had their thyroid gland(s) excised (one of those hounds was my girl Shannon-- she had classic signs of hypoT post surgery--her cholesterol was sky high as was her cTSH -it was just under 5-ref Idexx labs ). I think the point of posting that statement is it's extremely rare to find a hypoT hound and further bloodwork is recommended before starting supplementation.

If I could take a stab at it, Jen, since grey_dreams doesn't seem to be around just now...

 

People/vets have accepted T4 values of 0.0 - 0.2 as normal in greyhounds because the dogs appear normal from the outside and have low TSH values. If, however, the TSH values were high (and, I always add, if the dogs could actually tell us how they felt), then we'd define that level of T4 as too low. But we've accepted the non-specificity and low accuracy of the antibody to greyhound TSH, so we've accepted those low T4 values as normal for greyhounds. Thus, some hypothyroidism in greyhounds is missed. If I understood correctly.

that's exactly how Dr. Couto explains it.

[sarabz]

So I had posted my own thread but since this one has more traction -

With no other signs/symptoms,is a T4 drop from .9 to .5 in year concerning? Is it indicative that we should do a full panel? Vet wanted Bella to go on l-thyroxine for a month and retest.

[greyhead]

I don't have the definitive answer (and I doubt anyone else does either). Yes, it would concern me. Yes, I'd have a full panel.

 

I'm always concerned that there are signs and symptoms that are so interior to the dog that we don't observe them, so it may be a mistake to assume our observations are the end of it.

[greysmom]

So I had posted my own thread but since this one has more traction -

With no other signs/symptoms,is a T4 drop from .9 to .5 in year concerning? Is it indicative that we should do a full panel? Vet wanted Bella to go on l-thyroxine for a month and retest.

 

Since it's much cheaper to supplement for a month than to do a full thyroid panel, many vets make this suggestion. But testing *after* you begin supplementation is basically useless since you will automatically have an elevated reading, which is inaccurate.

 

In my own opinion, and if this was my dog - in the absence of any other clinical signs - unusual weight gain; hard, staring coat or unusual hair loss; sudden increase in anxious behavior; loss of appetite; loss of energy, lack of interest in normal activities. - I would NOT consider a drop such as you describe to be overly concerning. I would probably opt for a "watchful waiting" practice.