hyperthyroid "grey zone" - thoughts?

Doodle has been drinking and peeing a lot lately and also has quite elevated blood pressure.
The vet wanted to test him for possible hyperthyroid and I just got his test results back -- according to the Idexx report, he's in the "grey zone" *sigh... * I didn't get to talk to the vet - and of course I didn't WANT him to be positive... but hopefully this doesn't mean we "wait and do nothing".


T4 = 2.4 (0.5 - 4.7)
(2.3 - 4.7 is grey zone in old or symptomatic cats)
Free T4 = 2.8 (1.2 - 4.3)

On 3/24/2010 his T4 from was 2.0
and on 6/13/2009 his T4 was <2.0 on a snap test

I've read that increasing T4 values are indicative of hyperthyroidism even if the values are within normal limits.. Has anyone else ever heard or been told this?

 

That's a strange scale for his free T4. Do you know if it says "by equilibrium dialysis"? The free T4 test should always say "by equilibrium dialysis" or Free T4ED. Suspicious.

 

I don't know Jess. I got the results over the phone. She just gave me the values and supposedly the reference range. The vet is supposed to call me tomorrow .
Is there another way to do a free T4? A less accurate way? I'd hate to think this was a waste of time...

I'll ask tomorrow.
She also gave me some weird T3 number but I don't know why they ran that -- I thought that was some sort of "suppresion test" ?? And we didn't do anything other than draw blood on Friday.

 

Hmm. Methinks that's just the plain old Free T4 which is bupkis.

I wouldn't do anything based on the T4 result; there isn't much to talk about unless you have a Free T4ED that is very remarkable.

 

I keep deleteing expletives!

Does the fact that the T4 is increasing rather than decreasing mean anything to you?
I just hate not being able to help him!
They won't do anything to lower his blood pressure until they figure out if he's hyperthyroid and they can't figure what freaking tests to run to figure it out.
Geez this is frustrating!

So I need to ask them to run another T4 but to make sure it is T4ED - right?

 

Hi Michelle

A 2.0 to 2.4 isn't that eyebrow raising. True, the T4 tends to decline with age, so it's something to keep an eye on, but not jump to treat. Remember that methimazole is not benign--it is a tough medication so its use truly should be justified.

If your vet did not run the ED free t4, ask why not, and ask if it can be added on to the sample you already submitted. If not, you could wait three months and bring him in. Since according to the tests your vet ordered, Doodle is not hyperthyroid, she shouldn't have a problem with treating his hypertension. BTW if he is truly hypertensive, remember the standard is amlodipine, not enalapril/benazepril or atenolol.

 

My vet (and me) were very happy to get Sweety's T4 down to 3. (from <10, and fT4 <100)
Doodle's numbers are in the right range. I (not a vet) don't understand why they think your numbers are high...
I've read a lot about hyperT and never heard of the "grey zone". (but that doesn't mean anything.)

And Jess - Sweety is on Methimazole - what is tough about it? She's been on 5 mg/day for 7 months. We started out really low, a year ago, and slowly worked it higher. I know about the stomach problems, is that what you meant? Or the low WBC?

 

Hi Jayne

It can cause a loss of all types of blood cells, and platelets. There's the GI stuff, and the rare cases of liver toxicity. Like I said, can be a lifesaver, but should be reserved for those who we are *sure* need it. Risk v. benefit.

 

Thank You again Jess.
I understand what you are saying - and of course wouldn't want to try to force the issue with methimazole or any drug that wasn't neccesary.
Like I said, of course I'm glad that he's not hyperthyroid! I just tend to need confirmation or additional (often corrective) information from this board due to the fact that I'm not all that trusting of my vet's expertise. (or my own understanding)
If the "grey zone" just means to keep an eye on things then that is what I'll do.
My vet did say that her drug of choice for hypertension would be amlodipine.


Jayne, I admittedly don't know much about this. So I appreciate your input.
I believe my vet keeps referring to the "grey zone" because that term is used on the Idexx report. I don't think she has much experience with treating cats with any type of disorder - Doodle is 1 of 3 of her diabetic patients and she has said to me previously that most of her clients choose "not to treat" when there is an illness
I continue going there because she is more open minded and willing to work with me than most of the other vets in my area.
She is the only vet I was able to find that would agree to Rx Lantus and then Levemir and the only one that would agree to do a dental on Doodle with out pumping him full of vaccines first.

 

I wish I could turn back the clock, and not treat Bear for his hyperthyroidism when I did. We were happily ignoring that issue, but I went and pushed it, and we started him on Methimazole. I soon found out that his hyperthyroidism was keeping a lid on his kidney disease. The hyperthyroid treatment pushed his lightly simmering early kidney disease into something way more serious that needed treatment, and we are now in a very difficult situation with phosphorus binders and diet issues. I am not saying to be negligent, and ignore hyperthyroidism and CRF, but in Bear's case, I regret pushing the hyperthyroid tx when I did. Just be aware that treating hyperT can make the kidney issues worse. Always keep in mind, I am no expert on these matters, and that I am just sharing my personal experience.

 

Linda you bring up a very important point, and it's something I want to make very clear. Hyperthyroidism does not cause renal disease, and hyperthyroidism must be treated, no exceptions.

I'm not sure if you're saying that Bear was truly hyperthyroid, or if you feel you jumped the gun. If he was, he needed to be treated. He already had kidney disease but the hyperthyroidism was causing his blood to gush through his kidneys, decreasing the toxins (BUN and creat) that are now showing up in his bloodwork. He may have been working with both kidneys only at 20%, but the increased blood-rush through his kidneys masked this. (This increased blood-rush also damages the kidneys, BTW, so this 'mask' has its own complications.) So, if he has (for example) 80% loss of kidney function, he had it the day before he started the methimazole -- you just didn't know yet. Please don't feel that your decision to treat him is in any way to blame for his CKD.

I feel strongly about this because it's the truth, for one, and it's important to know all sides, and secondly because i have seen too many cats die from hyperthyroidism that was not treated or treated too late. Let me tell you, from what I've witnessed, there is no guilt like that of knowing your cat is dying because you dragged your feet in treating something you knew needed to be treated. I have seen more than one cat die from heart failure secondary to heart muscle changes caused by hyperthyroidism, and cats die from complications of hypertension and strokes, all related to hyperthyroidism. It is an ugly disease that causes a lot of suffering.

That said, I do *not* believe in treating for hyperthyroidism unless there is solid evidence of the disease. The medication is not benign, and we should also not look to squash the thyroid gland (which does good things!) unless it truly needs to be tamed. But treating a truly hyperthyroid cat for their disease? Yes, it's always the right thing to do.

 

But Linda, didn't the vet/staff also give the wrong dosing instruction for Bear's methimazole, resulting in overdosing (I think it was doubling the dose?) for a few weeks? I don't know if it dropped him too low, but hypothyroid states also have a negative impact on renal function. (eta: as opposed to euthyroid states, which unmask existing kidney disease).

 

Yes, that was part of the whole mess.

 

Linda, Jess is right. The renal problem was there, just being masked by the hyperthroidism. You didn't do anything wrong - you have to treat it or it causes many other organ issues, specifically heart problems.
Don't beat yourself up - it's obvious you care very much -
Have you checked out "Tanya's CRF" site? A LOT of great info. (sorry, I don't have a link)
Good luck.