Possible Hyper-T Cat Again after 2 Radiations!

CassandraApril 6, 2011

My 11 year old cat had radiation therapy for hyper-T when he was 7, then again two years later when he was 9. Now, two years after that second treatment he is exhibiting the symptoms of hyper-T again: rapid weight loss, nervousness. I am so distraught over this. I have not brought him back to the vet again because I don't know at the moment whether I should change vets to seek another opinion, a new type of treatment (if any) or something besides what obviously is not working. The I-131 was sold to me as a virtual "miracle cure"; and they insisted to me that a second round would, of course, work "this time." So I just don't know whether this vet is competent and I should return. They will no doubt talk me into a third round. I feel so, so sorry for my boy cat because of all he's been through so far. I wonder whether I should just give in to the fact that he is ill and let nature take its course. Can any experts weigh in here? What would you do?

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I used to work as a Vet Tech at a cat hospital . We saw a lot of cats with this condition. Your cat needs blood work, specifically a t-4. There are meds that can control this and they can be crushed and put it wet food. Yes, get a second opinion! Good luck to you!

Here is a link that might be useful: The Pet Nanny and Dog Walker

    Bookmark   April 6, 2011 at 11:09AM
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Marita, I've never heard of a third I-131 treatment!! But unless you have the full panel Thyroid test, you can't be sure, although the symptoms may be quite familiar to you by now!!
Something is not right! Your boy needs to find a new vet...
I am sending you a personal e-mail with more info.


    Bookmark   April 6, 2011 at 7:10PM
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I would also try to find a vet that specializes in cats....some type of cat clinic.

I'm a big believer in specialty clinics after a regular vet kept draining my billfold and my cat continued to be sick. The clinic I found cured my cat, saved me $$ in the long run, and was less expensive overall.

    Bookmark   April 6, 2011 at 7:20PM
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Hopefully Meghane will reply to this post. Before she became a vet, she worked for a time as a tech at a clinic that did I-131. I'm sure that her insights would be of greatest benefit on this thread. Until Meg shows up, I will hazard my best guess at what's going on with your cat. I believe I-131 clinics make a point of administering the lowest possible dose of I-131 that they believe will be effective in eliminating all diseased thyroid tissue. My guess is that the I-131 clinic you've been using has been a bit too conservative in their I-131 dosing of your cat. As a result, not all diseased thyroid tissue has been eliminated during treatment.

If I were you, I'd be inclined to find another I-131 clinic to perform the third, and hopefully LAST, I-131 treatment to your cat. Before scheduling your boy for any further I-131 treatment, though, you should ask the clinic owner for statistics regarding the clinic's success rate and repeat treatment rate so that you can accurately evaluate their history with this treatment.


    Bookmark   April 6, 2011 at 9:55PM
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I'm so sorry, I can't imagine how upsetting that must be.

Even if, at the moment, you feel you cannot put your kitty (and wallet) through another round of I-131, please find another vet and take him to be checked. You might decide to try medications for a while. Yes, it is inconvenient to give meds once or twice a day, but perhaps this would be the answer for him and you at the moment, if only short term until you decide to possibly go for a third treatment.

I have been giving my cat medication for hyper-t for 5 years now. It is hardly something I even think about any more. Her thyroid has proven very sporadic over those 5 years, and I've often wondered if she had I-131, if it would have actually worked for her or if her thyroid would have proven uncontrollable. About every 3 months she gets her dose changed and has slowly ranged back and forth between 2.5mg/day and 10mg/day. We are currently buying her meds at Walmart (but are thinking of switching to a vet pharmacy soon) and I figure we've probably averaged about $200/year on her medications.

I've also heard that medication for hyper-t can be gotten in a gel form that you rub inside their ears. So even if he is terrible to pill, there are even other options out there to control it.

But whatever you do, please try to find another vet and have him checked soon. It is my understanding that high blood pressure can become a problem in some cats with hyper-t and you certainly don't want to risk that- strokes, blindness, etc.

It will be okay. You do have options as far as how to treat him, if it is indeed hyper-t again, and nothing in written in stone at this point. You do not necessarily have to commit to another round of I-131 to keep him happy and healthy.

Thinking positive thoughts for you.

    Bookmark   April 7, 2011 at 3:37PM
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Of course quasifish is correct. I-131 is not the only treatment for hyperT. It is the only CURE (in most cases), but hyperT can be successfully managed with medication (methimazole or carbimazole). The medications are available in pills, liquids, flavored chews, and transdermal gels (these are applied to the inner ear flap). I have managed both of my hyperT cats with liver-flavored carbimazole-medicated chews that they LOVE and snarf down as treats, so there has been no difficult pilling involved.

You do need to get your cat to a vet for a Total T4 test to check his thyroid function. There's no reason to assume this is a recurrence of hyperT until you verify it with the appropriate test. If he is, indeed, hyperT again, you can discuss either medical management or another I-131 treatment at that point. First things first. Get the diagnosis.


    Bookmark   April 7, 2011 at 5:30PM
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I've seen a LOT of hyperT cats and I can remember exactly 1 that was under 10 years old at time of initial diagnosis. And this was a 1.5 year old siamese that was a total sicky-poo from day 1 and he had repeated elevated T4 plus tc-99 scans to confirm hyperT as nobody in his/her right mind would believe hyperT in a 1.5 year old cat. I wouldn't even TEST for it in a 7 year old cat unless I was completely at a loss for cause of symptoms and had run every other blessed test in the book. And even then, I would probably insist on tc-99 scan to double confirm, or even triple because I'd probably run the T4 at least twice- once as diagnosis and second time while on tapazole with a resolution of clinical signs to confirm normal T4. So I *have* to ask how were the previous 2 diagnoses made?

A second possibility is that you cat has a very rare thyroid carcinoma. Most thyroid tumors in cats are adenomas, which are benign and respond extremely well to usual doses of I-131. However I remember a cat who we initially treated at age 20, and T4 did not return to normal at 30 day recheck. We repeated treatment and T4 went down but was still not normal. Finally we did a biopsy of the thyroid and it was carcinoma not adenoma and we treated her a 3rd time at a MUCH higher dose which was curative at 1 year post treatment.

I agree with the others- get a diagnosis first. I can think of about a million different reasons for a cat to have weight loss and nervousness, and hyperT is not amongst the first 999,999 at age 7 or even at age 9. I truly wonder about those diagnoses and how they were done. At age 11 I can believe hyperT but unless he has a thyroid carcinoma I can't make this case make sense.

We treated on average 4 cats per week with I-131 when I was a tech, which I did for 9 years. I have a very good memory for things out of the ordinary and am positive that I would have remembered treating a 7 year old cat, and retreating at 9 years if it had happened. It just didn't though. I am sure that the youngest we saw was that siamese and after that I think the youngest was 11 at first diagnosis. The only confirmed carcinoma was in that 20 year old cat. I can think of a couple of repeat I-131 treatments but they were all in older cats (12+ years) who failed to respond at the 30 day recheck. I even remember a cat who had both thyroid glands removed by the referring DVM and owner was thinking about suing for malpractice because cat was STILL hyperT. But we did a tc-99 scan which proved there was hyperT thyroid tissue in thoracic cavity and we did the treatment and he was fine for 3 years at least.

I know you are totally distraught over your poor cat. Has he ever had diarrhea or vomiting, or weight loss despite an increased appetite? These are what I would consider hallmarks of hyperT4, not just weight loss (unless appetite was increased as well) and nervousness. I mean, cats are nervous species and if not eating of course weight loss ensues but inappetence is NOT a sign of hyperT4.

Please get a diagnosis on your kitty. I hope you can get records of previous treatment including full labs and diagnostic T4 along with post-treatment T4. We usually got T4 level at 30 days, 60 days, and 1 year post-treatment and only with normal t4 for all 3 rechecks did we call the treatment a success. We were 98% successful, and we treated a LOT of cats.

    Bookmark   April 7, 2011 at 11:00PM
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Curious as to what were the 2% failures your clinic experienced treating these hyperthyroid cats with I131. Seems like that is not a bad success rate, but were the failures the rare carcinomas? I have treated many hyperthyroid cats and sent a lot for radiation therapy and to have to treat a cat a second time is not that incredibly unusual (even with adenomas). Cats that have thyroid tissue along the trachea are often the carcinoma cats, which, for some reason, are not as rare out here in California (I would say at least 5% have carcinomas). Not had a patient need a third treatment, but I dont' think that's unheard of.

However, I am pretty sure any place that has the equipment and sophistication to use radioactive materials like I131 also has gamma cameras and nuclear scintigraphy, and would be very likely to confirm a diagnosis of hyperthyroidism before treating a cat. Is this place different than that? We only have a few places in this entire state that treat hyperthyroid cats and none would even remotely consider treatment without documenting the disease exists (way too many legal issues when it comes to radiation to willy nilly treat a cat with weight loss with radiation without doing the other work first). Before a third treatment is done, I would certainly make sure a nuclear scan verifies active thyroid tissues... and if it does, perhaps those tissues need to be biopsied before the scan to see if it's something 'bad'. Still, you would think a good dose of I131 would still take care of the problem (just as it does in people with thyroid cancer).

As mentioned above, there are a lot of other reasons an old cat can have symptoms of weight loss, even with a good appetite (IBD is a common one) so don't just assume it's the same disease coming back again.

    Bookmark   April 8, 2011 at 11:52PM
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My cat was diagnosed with hyperthyroidism in 2004. He was put on Tapazole and was stabilized and maintained very well on his meds. He lived a very long, healthy and happy life. At the end of last year he starred losing weight and his levels were elevated and we increased his dosage. My vet suspected based on his test results and the fact that his levels were high and he continued to lose weight that his thyroid had become cancerous. Without a biopsy there was no way to know for sure and I elected not to put him through that at his very advanced age. She said he would not be in any pain - it would feel like a lump in his throat. Today I am putting him down. He is weak and just stopped climbing in his condo and doing his "chicken cry" at night. I am devastated to lose him but I have absolutely no regrets about how we treated his disease and the very long and happy life he has lead.

    Bookmark   April 16, 2011 at 7:03AM
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99.9% of the time, hyperT4 is an obvious diagnosis based on clinical signs, chemistry, and T4 results. We were referred some patients who fit the clinical signs but the chemistry and T4 didn't really seem diagnostic. For example, we had referrals for cats with a 3.5 T4 level (normal 1.0-4.0) just because ALT was high, maybe a heart murmur, and cat was losing weight. Well, I can think of a lot of other reasons for those things to happen but a T4 of 3.5 is NOT diagnostic of hyperthyroidism and we didn't treat those cats.

We didn't have a nuclear scintigraphy available in the hospital but did refer several cases that were weird to confirm. One cat had 2 thyroidectomies and was still hyperthyroid. Tc-99 confirmed thyroid tissue throughout thoracic cavity and NOT in thyroid cartilage. So rDVM had successfully removed thyroid tissue in neck but cat had hyperthyroidism from tissue in thoracic cavity. However no need to check every single cat if all lab work and clinical signs fit.

It was incredibly rare for anyone to biopsy a thyroid because carcinoma was so rare and really most of the time it still responded to a regular dose of I-131 so it didn't matter. Just that one case was odd and owner was willing and able to afford biopsy and that's what it was. We had very few re-nukes but when it occurred we didn't necessarily biopsy or Tc-99; just went off the still-elevated T4 (usually at 90 days post Tx).

Renee I am sorry to hear about your cat. But it sounds like it is time and you made the right decision. You gave him a good long happy healthy life for as long as he had.

    Bookmark   April 17, 2011 at 2:28AM
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I'm the OP and I wanted to give an update. After his second I-131 in Dec. 2008 (the first one was in March 2007) the T-4 values are again steadily climbing. They were borderline high--4.5--in the blood test done soon after I posted this last summer. Now they are 6.7.

My vet recommended a third I-131 but frankly did not think with this history that the results would last. I have declined to do it again due to expense and trauma--for both me, emotionally, and for the cat.

As the only course besides doing nothing and letting him die, I have opted for pilling him with methimazole. We began the regime today and he will be re-tested in a few weeks.

I am heart sick and an emotional wreck over this whole situation. While billed as some type of "miracle cure," the I-131 has been both enormously expensive and has failed my cat twice. U have searched the web for any other experiences like this and no one seems to have any at all. My poor boy is only 12 years old.

    Bookmark   January 18, 2012 at 3:13PM
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Was he tested for Addison's disease? My niece has it, and had hyperthyroidism. They insist there's no correlation, and usually it'd be a reverse effect, but you never know.

And her endocrine system as a whole is messed up. I don't see how they're not all related.

    Bookmark   January 20, 2012 at 2:15PM
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Hi Marita, it is good to see an update from you. It sounds like you are very disappointed with the situation, but I am glad you have your cat on meds now. I still have my old girl and am pilling her twice a day still. It is a pain to get into that routine, but both of you should get use to it in time. I barely even think about pilling my old girl anymore, it's just something I do while DD is getting ready for school in the morning, and during bedtime routines at night.

I'm sorry the I-131 did not work for you. My knowledge on that front is very limited. I'm sorry it failed your kitty twice, and I hope you find that giving methamizole is not that bad. Good luck to you and your cat.

    Bookmark   January 20, 2012 at 3:55PM
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