 |
 | Home | Contact Us | FAQ | Search & Site Map | Link to Us |
 | Sign In | Join | Other 45 Sites in Network |
| HomeDiscussion GroupsGeneral TopicsCat AnecdotesHealth and BehaviorRescue CatKB.com Contact UsLink To UsSearch & Site Map |
Cat Forum / Health and Behavior / December 2003Hyperthyroidism
Just got the (pre dental)lab results back for my 14 yr old tabby and found out that he has a T4 of 118 nmol/L. The dental cleaning will be delayed until his thyroid condition is under control. We have decided that pilling him with Tapazole is not an option because he hates pilling and even goes through a personality and behavioral change when subjected to pills. We considered surgery but was told that thyroidectomy is a precise surgical procedure with some risk and often results in hypothyroidism and then we're back to pilling again. So Zak is going to Thames Valley Vet Services www.tvvs.ca on Jan 10 for radioiodine treatment and will be an in-patient for a week. Thames Valley Vet Services is located in London, Ontario on the campus of St. Joseph's Health Care London. The facility is part of the Lawson Health Research Institute. As the research arm of the London Health Sciences Centre, the LHRI is one of Canada's three largest hospital-based research institutes. I feel he will be in good hands and they say Zak is a very good candidate due to his excellent renal and other numbers. I'll post a follow up in January including the interesting experience of banning a radioactive lap cat from the bedroom for 3 weeks :-) -mhd > Just got the (pre dental)lab results back for my 14 yr old tabby and > found out that he has a T4 of 118 nmol/L. The dental cleaning will be [quoted text clipped - 18 lines] > and they say Zak is a very good candidate due to his excellent renal > and other numbers. I'd still suggest trying him on tapazole for a while in case treating the hyperT unmasks latent kidney disease (excellent renal numbers won't necessarily stay that way after I-131). There are so many cats on the CRF list who were only diagnosed with CRF after treatment for hyperT. You might be able to obtain the tapazole in compounded form to avoid giving pills. http://www.felinecrf.org/related_diseases.htm#hyperT_treatments HTH Helen >I'd still suggest trying him on tapazole for a while in case treating the >hyperT unmasks latent kidney disease (excellent renal numbers won't >necessarily stay that way after I-131). There are so many cats on the CRF >list who were only diagnosed with CRF after treatment for hyperT. You might >be able to obtain the tapazole in compounded form to avoid giving pills. He will be having an Feline Early Renal Detection test just before he goes in as I know blood tests are not that indicative. This is a new procedure and is very accurate. -mhd > >I'd still suggest trying him on tapazole for a while in case treating the > >hyperT unmasks latent kidney disease (excellent renal numbers won't [quoted text clipped - 5 lines] > goes in as I know blood tests are not that indicative. This is a new > procedure and is very accurate. I read your other posts and I don't think the ERD is as accurate or reliable as you seem to think it is. We've used it.... The ERD is a screening test - not a definitive renal function test... - It detects nephron damage - it doesn't measure actual renal function.... nor can it predict renal function after I-131 tx. Also, the results can be affected by a slew of conditions other than CRF. I wouldn't make any irreversible decisions based on the results of the test. The smart play would be treating your cat with methimazole for a month or two and closely monitoring kidney function (BUN/Cr) while on the medication. If his kidney function remains stable when he reaches euthyroidism - then I-131 may be an option -although I wouldn't opt for I-131tx for a 14 y/o cat... If azotemia develops or worsens when he reaches euthyroidism you can adjust the dosage until you strike a balance between an "acceptable" level of hyperthyroidism and an "acceptable" level of azotemia... You don't have this safety and flexibility with any other txs. Think about it. Good luck. Phil >I read your other posts and I don't think the ERD is as accurate or reliable >as you seem to think it is. We've used it.... The ERD is a screening [quoted text clipped - 3 lines] >conditions other than CRF. I wouldn't make any irreversible decisions >based on the results of the test. Hmmnn, I was getting the impression it was the holy grail of testing. >The smart play would be treating your cat with methimazole for a month or >two and closely monitoring kidney function (BUN/Cr) while on the medication. [quoted text clipped - 6 lines] > >Think about it. I've heard enough so far of the above advice that I'm going to reopen discussions with my vet and the specialists. I will post the summary of my discussions as soon as I can reach them on Monday. Thanks Phil and everyone else who also expressed the same concerns. -mhd > >I'd still suggest trying him on tapazole for a while in case treating the > >hyperT unmasks latent kidney disease (excellent renal numbers won't [quoted text clipped - 5 lines] > goes in as I know blood tests are not that indicative. This is a new > procedure and is very accurate. It's promising for detecting early CRF in itself, but it's not overly specific, so I would not rely on it for making a decision regarding the use of I-131. You might want to consider the iohexol clearance test which was mentioned in the link I sent you, but I don't know if you can get that run in Canada. HTH Helen >It's promising for detecting early CRF in itself, but it's not overly >specific, so I would not rely on it for making a decision regarding the use >of I-131. You might want to consider the iohexol clearance test which was >mentioned in the link I sent you, but I don't know if you can get that run >in Canada. I am now going to reexamine the I-131 treatment we had decided on. As I explained in a recent previous post I am now going to discuss all possibilities of CRF with my vet and the clinic (www.tvvs.ca). I am especially interested in this iohexol treatment mentioned in your link and it's availability in Canada. Hopefully the clinic can perform this procedure since the facility is part of the Lawson Health Research Institute. As the research arm of the London Health Sciences Centre, the LHRI is one of Canada's three largest hospital-based research institutes. I am a little confused about the CRF issue however. If the thyroid condition is masking an underlying CRF condition, is the implication that the CRF will get worse or just will expose itself. Does it have to get worse to expose itself, or will a thyroid procedure unmask a condition at its current numbers? Thanks -Maurice > >It's promising for detecting early CRF in itself, but it's not overly > >specific, so I would not rely on it for making a decision regarding the use [quoted text clipped - 8 lines] > I am especially interested in this iohexol treatment mentioned in your > link and it's availability in Canada. There's a much better and much more accurate renal function test than iohexol. The nuclear med facility that offers the I-131 tx probably also offers planar renal scintigraphy (a/k/a quantitative renal scintigraphy) -- because PRS uses the same principal and equipment as I-131tx. PRS is so much better than iohexol because you can quickly and *noninvasively* measure total and *individual* kidney function (GRF) in *awake* cats! The procedure takes about 10 minutes and doesn't require overnight hospitalization. Hopefully the clinic can perform > this procedure since the facility is part of the Lawson > Health Research Institute. As the research arm of the London Health > Sciences Centre, the LHRI is one of Canada's three largest > hospital-based research institutes. Sounds like a top-shelf facility - I'd be very surprized if they didn't offer PRS. > I am a little confused about the CRF issue however. If the thyroid > condition is masking an underlying CRF condition, is the implication > that the CRF will get worse or just will expose itself. > > Does it have to get worse to expose itself, or will a thyroid > procedure unmask a condition at its current numbers? Hyperthyroidism masks true renal function because it falsely elevates GFR by increasing both, the heart's output and renal blood flow -- the volume of blood flowing through the kidneys to be filtered. This gives the impression that the kidneys are filtering more blood than they actually are instead of at just higher rate. Kinda like a clogged oil filter that cleans more oil only because the engine is revving faster. After hyperthyroidism is treated, cardiac output, renal blood flow and true GRF slow down to their normal rates which will unmask CRF in cats with underlying disease. If the cat doesn't have underlying CRF, GRF will not slow down enough to cause develoment of overt renal failure. IOW, treatment doesn't cause or worsen CRF, it simply unmasks the true GRF. HTH, Phil > Thanks > -Maurice >There's a much better and much more accurate renal function test than >iohexol. The nuclear med facility that offers the I-131 tx probably also [quoted text clipped - 5 lines] >*awake* cats! The procedure takes about 10 minutes and doesn't require >overnight hospitalization. >Sounds like a top-shelf facility - I'd be very surprized if they didn't >offer PRS. They do Gamma Scintigraphy but no mention of the planar renal test. Here is a link to the Scintigraphy service at the clinic http://www.tvvs.ca/scintigraphy_frameset.htm I will ask therm tomorrow. Thanks for the info. -mhd > >There's a much better and much more accurate renal function test than > >iohexol. The nuclear med facility that offers the I-131 tx probably also [quoted text clipped - 19 lines] > > -mhd As good as PRS is -- it still won't give you an accurrate assessment or prediction of renal functon after tx if you run the test while the cat is still hyperthyroid. PRS and iohexol both depend GRF to determine renal runction - Hyperthyroidism falsely elevates GRF - so the results you get won't be accurate. Without invasive tests, the only way you'll know if his GFR will slow down enough after tx to unmask CRF is to measure his renal function when he reaches euthyroidism while taking Tapazole... This is what his true renal function should be after treatment when his T4 levels are normal. Btw, the most accurate T4 test is fT4ED. Good luck. Phil >IOW, treatment doesn't cause or worsen CRF, it simply unmasks the true GRF. So aren't we basically facing CRF anyway and shouldn't be avoiding getting his thyroid to function properly? Or is elevated GRF from hyperthyroidism tolerated to a certain extent as a lessor of 2 evils? He does need dental work that has been delayed because of the hyperthyroidism and I don't really see any option but to get him to reach euthyroidism through treatment. I just got back an email from TVVS with the following information... "One more test that can be run at your home clinic is to run a creatinine test, this is also a kidney enzyme that can give us an idea of how the kidneys are functioning. The other thing that I would consider is to give a low dose injection of 131-I to gradually bring the T4 down (this would mean that cat could go home the same day). We do this method with cats that we know are at risk with their kidneys and so far this has been an excellent way of treating them. The only disadvantage is that we would need to repeat the bloodwork in 12 weeks and give another low dose injection. It is even possible that your cat may need a third injection." Any comments on the above Phil? -mhd > >IOW, treatment doesn't cause or worsen CRF, it simply unmasks the true GRF. > > So aren't we basically facing CRF anyway and shouldn't be avoiding > getting his thyroid to function properly? Absolutely! Thyrotoxicosis affects virtually every organ system in the body - especially the cardiovascular system and the skin - can cause retinal detachment secondary to hypertension and myocardial hypertrophy (thyrotoxic heart disease) similar to hyperthrophic cardiomyopathy. Or is elevated GRF from > hyperthyroidism tolerated to a certain extent as a lessor of 2 evils? Elevated GRF isn't a problem in itself because it augments renal function. The causes of elevated GRF are the problems. Cats with severe or end-stage CRF would probably benefit more by not treating the thyrotoxicosis because it augments GFR -- unless the clinical signs of thyrotoxicosis were so severe or unmanageable -- like if the cat develops congestive heart failure secondary to thyrotoxic heart disease, there'd probably be no choice but to treat the hyperthyroidism. In this case, an antithyroid drug would be the treatment of choice because the dosage can be adjusted accordingly - up or down. The cat could be left mildly ("acceptably") hyperthyroid and/or mildly (acceptably") azotemic - so neither parameter is in the critical area. > He does need dental work that has been delayed because of the > hyperthyroidism and I don't really see any option but to get him to [quoted text clipped - 5 lines] > creatinine test, this is also a kidney enzyme that can give us an idea > of how the kidneys are functioning. No no no... Creatinine clearence test also relies on GFR to determine renal function. Thyrotoxicosis falsely elevates GRF so the results won't refect the true renal function. The *only* way any GRF test will yeild an accurate result is when the GRF isn't affected by thyrotoxicosis or any other illness or condition. > The other thing that I would consider is to give a low dose injection > of 131-I to gradually bring the T4 down (this would mean that cat [quoted text clipped - 7 lines] > > Any comments on the above Phil? Three treatments? That's absurd. They're just trying to push the I-131 tx. You can eliminate all this trouble and triple expense and stress for the cat by simply beginning Tapazole tx at an initial low dose and gradually increasing the dose by 2.5 mg every 2 weeks until his T4 is in the normal range and see where his BUN/Cr are. Its a very simple process... Phil > -mhd <snip> > We have decided that pilling him with Tapazole is not an option > because he hates pilling and even goes through a personality and [quoted text clipped - 3 lines] > surgical procedure with some risk and often results in hypothyroidism > and then we're back to pilling again. <snip> FWIW, my mother (a human, not a cat) had radioiodine treatment and it resulted in hypothyroidism and daily pills. While certainly preferable to surgery, you may end up having to pill your cat, anyway. Regardless, I hope it works out for your cat. Good luck! rona  Signature***For e-mail, replace .com with .ca Sorry for the inconvenience!*** >FWIW, my mother (a human, not a cat) had radioiodine treatment and it >resulted in hypothyroidism and daily pills. While certainly preferable to >surgery, you may end up having to pill your cat, anyway. So did my sister-in-law. Apparently in humans they often destroy the thyroid whereas with cats they take a "just enough to get the job done" approach. The clinic will be giving him 2.5 units which is conservative. -mhd Hi, My cat had the radioactive iodine done 2 years ago in January. At the time she was 10, and I couldn't imagine giving her a pill every day for the next 5-8+ years. She did very well with it - only one dose worked fine. I was never told that she became hypothyroid. The biggest thing they stressed after the treatment, was that the litter would be radioactive and had to be flushed down the toilet instead of thrown out in the trash, for a period of about 3 weeks. I never regretted doing the treatment, even though it cost $1000! It was worth it not to have to deal with the pills. Please Please Please, after this is done PLEASE have your cat monitored closely. A year after the hyperthyroidism she developed kidney disease, then high blood pressure, and eventually went blind due to retinal detatchment from high blood pressure. I'm not saying that these were caused by the radio iodine - absolutely not - but they are all inter-related, and depending on how long your cat has been hyperthyroid, some of his other systems may have been compromised. Just follow your vets suggestions and keep monitoring his blood work, and everything should go ok. Meghan > Just got the (pre dental)lab results back for my 14 yr old tabby and > found out that he has a T4 of 118 nmol/L. The dental cleaning will be [quoted text clipped - 23 lines] > > -mhd >Hi, > [quoted text clipped - 5 lines] >flushed down the toilet instead of thrown out in the trash, for a period of >about 3 weeks. I use flushable anyway but will be saving the liners for 3 weeks before disposing. The garage makes a good deep freeze up here in Canada :-) >I never regretted doing the treatment, even though it cost >$1000! It was worth it not to have to deal with the pills. [quoted text clipped - 6 lines] >depending on how long your cat has been hyperthyroid, some of his other >systems may have been compromised. Monitoring for the next year is part of the procedure. My regular vet can do the tests and just bills the clinic for the testing. They also offer a free top-up procedure if he needs it, which is just a day procedure. Sometimes top-ups are needed because they take a very conservative dosage approach. They apparently have a much less than the 2.5% hypothyroid statistic which is rate in cats. Since my vet now offers the Early Renal Detection testing which exposes problems much earlier than blood panels, I will be doing that for the rest of his life. We did catch this early as his T4 6 months ago showed a normal range. -mhd >Just follow your vets suggestions and keep monitoring his blood work, and >everything should go ok. [quoted text clipped - 28 lines] >> >> -mhd -- "Staccato signals of constant information..." ("The Boy in the Bubble") Paul Simon > Hi, > [quoted text clipped - 19 lines] > > Meghan I think that's why it's often suggested that Tapazole/methimazole (generic of Tapazole) be tried first, before the radioactive iodine treatment. In case treating the hyperthyroidism unmasks CRF. You made an excellent point, re: high blood pressure. It can be associated w/ either of these diseases, & if left untreated can result in blindness. Otoh, even if the bp is not diagnosed & the cat does goes blind, as long as one realizes *quickly* what's going on & the high bp is treated ASAP, it's possible for the retinas to reattach & the cat's vision to return. Just in the last couple of years, more & more vets are now equipped to take a cat's blood pressure. It used to be *very* difficult to find a vet who had the equipment & skill to take a bp reading. For ex., In the spring of 2001 I needed to go to an internist/oncologist over an hour away to get my CRF cat's bp read. The next closest was a practice near Ithaca/Cornell, which is 2 hours from here. (Yes, it was high, & required med.) But within several months after that, my own vets' practice - 4 minutes from my house - was then equipped to do it. Cathy > > Just got the (pre dental)lab results back for my 14 yr old tabby and > > found out that he has a T4 of 118 nmol/L. The dental cleaning will be [quoted text clipped - 23 lines] > > > > -mhd >Just got the (pre dental)lab results back for my 14 yr old tabby and >found out that he has a T4 of 118 nmol/L. The dental cleaning will be [quoted text clipped - 23 lines] > >-mhd Just wondering -- could tapazole be made in a liquid solution? Hi. My 9-year-old cat is hyperthyroid. She was unable to tolerate the oral pills of Methimazole, so I give her a transdermal form that has to be specially prepared by a compounding pharmacist. I put it inside of her ear near the tip, and the medicine is absorbed through the skin. I've been doing this for about 1.5 years now, and it's working out well. If it stops working, I will probably consider the radio-iodine treatments.
|
Reply to this Message |
 Sign In
 Join
 My Latest Posts My Monitored Threads My Blog My Photo Gallery My Profile My Homepage Start New Thread Enable EMail Alerts Rate this Thread
|
©2008 Advenet LLC Privacy Policy - Terms of Use
This website includes both content owned or controlled by Advenet as well as content owned or controlled by third parties.