Renal disease and thyroids

Re: Renal disease and thyroids

Hannah Wynne Richards — Mon, 01 Aug 2011 12:20:40 GMT

Yes but until the research is done, we can't know whether it will become proven and accepted therapy in the future

Wynne

Re: Renal disease and thyroids

Martin Atkinson — Mon, 01 Aug 2011 11:30:46 GMT

[quote user="Julian Earl"]

Anyway, Mark is making a separate point to you Martin surely, and one that points towards supporting my query /suggestion? Good hypertension becomes bad hypertension when it causes more damage to the kidneys etc., instead of just helpfully increasing renal perfusion. Whether such a crossover point exists I do not know, which is partly why the question was asked in the first place.

Also, I object strongly to being called unethical - it would be unethical if it would cause more harm than good, but not if the other way round. Which is exactly why I raised the analogy of using steroids for allergic disease - not exactly harmless are they?

[/quote]

I don't think there is such a thing as good hypertension, that is an overly simplistic idea, it is all bad, just that in some cases it may not be bad enough to cause obvious undesirable symptoms.

In all the exitement I can't remember if I mentioned the word unethical (loony yes), but if I did I wouldn't have said you were unethical Julian. But the idea of creating iatrogenic disease without proven benefit is in danger of being unethical and if something went belly-up as result you would have a hard time defending it. There is no analogy to using cortico-steroids for allergic disease, although I am very anti-corticoids, it is proven and accepted therapy.

Re: Renal disease and thyroids

Julian Earl — Sat, 30 Jul 2011 20:21:22 GMT

[quote user="Martin Atkinson"][quote user="Mark Holmes"]

Maybe I have missed a significant point but, my understanding of hypert4 and CCD is that the hypertension produced by HT4 increases GFR and improves renal function. Yet we are encouraged to look for and treat hypertension in CCD cats? At what point does good hypertension become bad hypertension?

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You're right Mark you have missed the point which came in my first post on this thread, it has already been shot down in flames but as it was my understanding too we're apparently both as dim as each other.

[/quote]

Apologies for missing the continuation of this thread but two days CPD has been in the way.

The fundamental question remains: would a low dose of Soloxine or whatever be possible in order to improve renal function without causing a significant degree of hyperthyroidism? I agree that there would be an issue with titrating any T4 dose precisely, and even in monitoring precisely as well. If the answer is we don't know enough yet then fair enough, but dismissing the idea as wrong is, in that case, pretty daft as well.

Re: Renal disease and thyroids

Martin Atkinson — Sat, 30 Jul 2011 11:15:24 GMT

[quote user="emerald"]

There may be another thread on this, but does anyone have more info about the skin buttons for fluid supplementation? Thanks

[/quote]

By anyone do you mean anyone else other than me or just more information? My experience is limited to 3 cats all in terminal stages of renal failure BUN >40mmol/l, Crea >300umol/l, Phos >3mmol/l USG < 1.015, UP/C ratio >5. All 3 required diuresis/dialysis to keep these figures from going exponential and were showing a combination of other signs of renal failure including seizures, cachexia, anorexia, anaemia and oral lesions. The 2 with the greatest azotaemia (50-60mmol/l) had owners who had varying degrees of (in)competance at giving fluids through the button so they received very little additional fluid and they died two weeks after implantation. The third which had a BUN of 41 had an owner who was very dedicated and very competant and was able to give 200ml saline through the button daily. All were on other treatment concurrently: renal diet, phosphate binder, Fortekor, anaboilcs and Vit B12, anti-epileptics and EPO for anaemia where appropriate. Client 3 brought the cat to me for a 2nd opinion after his previous vet who had been diuresing it with IV fluids said it should be PTS, and had good quality of life for 11 weeks post implantation. My goal is to get someone with a cat with severe CKD but which is not in terminal renal failure treated this way to see just how long it can live. Trouble is that could be months and how long would a client be happy to give fluids this way? There is precious little information on skin buttons in the UK but in the US there are reports of cats living years. The only problem we had with cat 3 was that after 5 weeks the fluid stopped dissipating as rapidly from the injection site and I wondered if some sort of cystic cavity had formed, this problem didn't occur when supplementary fluids were given via hypodermic needle at a different site. I'm planning on writing this up more fully as a case history for Vet Times.

Re: Renal disease and thyroids

Hannah Wynne Richards — Sat, 30 Jul 2011 10:28:24 GMT

I stick to the jury is still out viewpoint-but won't be giving soloxine to kidney cats just yet !

Wynne

Re: Renal disease and thyroids

emerald — Sat, 30 Jul 2011 10:27:50 GMT

[quote user="Martin Atkinson"]

Far more logical to treat the renal disease with conventional means (diet, ACEi, phosphate binders etc) and supplement with fluids at home via a skin button to maintain renal perfusion as it is relative dehydration that is the biggest enemy in cats with renal failure.

[/quote]

There may be another thread on this, but does anyone have more info about the skin buttons for fluid supplementation? Thanks

Re: Renal disease and thyroids

Martin Atkinson — Fri, 29 Jul 2011 17:19:17 GMT

[quote user="Mark Holmes"]

[/quote]

Re: Renal disease and thyroids

Hannah Wynne Richards — Fri, 29 Jul 2011 15:15:59 GMT

At the moment we don't know

Wynne

Re: Renal disease and thyroids

Mark Holmes — Fri, 29 Jul 2011 15:04:49 GMT

Re: Renal disease and thyroids

Hannah Wynne Richards — Fri, 29 Jul 2011 14:54:29 GMT

Interesting idea-but I'm definitely not brave enough to try it .

Possible PhD for someone tosettle the argument

Wynne

Re: Renal disease and thyroids

Mark Hedberg — Thu, 28 Jul 2011 21:15:45 GMT

[quote user="Kate Richardson"]

Yeah if you don't treat them! Or if your control is poor. The idea here is not to make them clinically hyperthyroid, but to mildly increase their T4 levels. How often do we monitor T4 levels in a cat diagnosed with renal disease, hardly ever I would suggest unless clinical signs change. It is well known that T4 levels can and often will be low in a sick animal, so it is quite possible that supplementing thyroxine may just bring the T4 into the normal range and this may in theory be enough to support renal function. It might not even be necessary to have the T4 higher than normal if the renal cat's T4 is say 10, it may be enough to increase it to 30-40.

[/quote]

Well, do people test t4 in a ckd cats routinely? It's certainly food for thought - after all, it's true that not all kidney cats are hypert4. Bit of a tangent, but just a thought.

I do when the heart rate is high or you get the classic hypert4 symptoms, but might be a thought to go more general.

Re: Renal disease and thyroids

Kate Richardson — Thu, 28 Jul 2011 19:55:17 GMT

[quote user="Martin Atkinson"]

Personally if BP is >160mmHg I am concerned, especially if I have a disease where hypertension is common- in an asymptomatic cat with a BP of 160-180mmHg I would repeat it and if persistently at this level, I would then treat the hypertension and start looking for the underlying disease.

[quote user="Martin Atkinson"]Even if they are not hypertensive what is driving the increased GFR? Simplistically maybe its the hyperthyroidism induced tachycardia just making the blood flow faster? There is no direct physiological effect thyroxine has on the glomerulus that I'm aware of, if there is perhaps someone could enlighten me, I'm as always happy to be proved wrong.[/quote]

Not all cats with hyperthyroidism are tachycardic, so am not sure that explains it.

[quote user="Martin Atkinson"]Still Loony OP or not its a good cause for discussion.[/quote]

Agreed and I'd also just like to make it very clear that my thoughts on this subject are very much on a theoretical basis, I'm not about to go and start experimenting with soloxine!

Re: Renal disease and thyroids

Martin Atkinson — Thu, 28 Jul 2011 11:07:00 GMT

[quote user="Kate Richardson"]

How often do we monitor T4 levels in a cat diagnosed with renal disease, hardly ever I would suggest unless clinical signs change. It is well known that T4 levels can and often will be low in a sick animal, so it is quite possible that supplementing thyroxine may just bring the T4 into the normal range and this may in theory be enough to support renal function. It might not even be necessary to have the T4 higher than normal if the renal cat's T4 is say 10, it may be enough to increase it to 30-40.

[/quote]

I test for renal function every 3 months in CKD cats and include ALT/ALP, if they were raised I'd test T4 but admittedly I wouldn't be testing to see if it was low - does anyone? Does hypothyroid sick syndrome occur in old cats with CKD? If it does, in any case, does it have any clinical symptoms or is it just the thyroid automatically reducing thyroxine production in response to feedback because of increased metabolic rate due to concurrent illness such as pyrexia and causing us difficulty in diagnosing hypothyroidism?

There seem to be 2 camps developing here the majority that think the OP is seriously flawed to the point that it is unethical and a couple who would consider it.

Regarding previous posts questioning my assertion that hypertension, systemic or glomerular, is driving increased GFR, it may be that not all cats with hyperthyroidism or CKD are hypertensive but it depends what ranges you use: some consider <200 to be of little concern some think that over 160 shows hypertension. Even if they are not hypertensive what is driving the increased GFR? Simplistically maybe its the hyperthyroidism induced tachycardia just making the blood flow faster? There is no direct physiological effect thyroxine has on the glomerulus that I'm aware of, if there is perhaps someone could enlighten me, I'm as always happy to be proved wrong. Still Loony OP or not its a good cause for discussion.

Re: Renal disease and thyroids

Kate Richardson — Thu, 28 Jul 2011 10:25:51 GMT

[quote user="David Mills"]

The rationale is sound, if a little naive - taking the 'good' bits of HT and applying them in some easy theoretical situation so that you can give just enough soloxine to keep them just above normal t4 levels - come on. In my understanding the good bits only come packaged with the bad bits and cats die sooner, go blind, hypertrophy their hearts much quicker with HT than CKD. Soloxine is a bugger too to get staedy state levels. Ethically unsound too - a HT cat is not a happy cat.

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Re: Renal disease and thyroids

nikki — Wed, 27 Jul 2011 23:57:10 GMT

i thought more recent thinking was not to try and balance hyperT4 and renal diz but to treat the hyperT4 so the TT4 is in the desired range (definitely not too low but equally not making an effort to leave it marginally high) - the thyroid diz is more important than the renal diz. therefore trying to increase a renal cat's TT4 to above the normal ref range (even slightly) would def not be desired.

Re: Renal disease and thyroids

David Mills — Wed, 27 Jul 2011 21:54:14 GMT

Re: Renal disease and thyroids

Julian Earl — Wed, 27 Jul 2011 14:02:08 GMT

See Martin, not everyone thinks I am a loony. At least someone agrees with my rationale.

Anyway, there's no reason why you couldn't maintain fluid intake and increase renal perfusion without causing a clinically significant rise in BP. I would agree that treatment for renal disease is making the best of a bad job, but maybe, just maybe, this would be of additional benefit.

Re: Renal disease and thyroids

Kate Richardson — Wed, 27 Jul 2011 12:47:00 GMT

I think its quite an interesting idea, and I don't know that I would immediately dismiss it. I thought hyperthyroidism actually caused an increase in glomerular filtration rate, which is not necessarily the same thing as renal hypertension. Not all cats with hyperthyroidism have hypertension, in fact I would say the majority that I see don't and I do measure BP on pretty much all of them, in fact I do it as part of a general health check for vaccination in most cats over the age of 10. Newly diagnosed hyperthyroid cats with levels say between 60 and 80 are probably less likely to be hypertensive than ones with T4 > 100. And not all cats with renal disease are hypertensive either. I would think it theoretically possible to increase T4 marginally by supplementing thyroxine without causing hypertension so there would be no indication to then use amlodipine.

I totally agree with you Martin that fluids are the key treatment with renal disease, absolutely no doubt about that. Obviously fluids will maintain hydration, but are they also improving GFR as well?

Close monitoring of T4/urea/creat/BP/HR/weight etc would obviously be essential to get the balance right.

Re: Renal disease and thyroids

Martin Atkinson — Wed, 27 Jul 2011 11:31:29 GMT

I don't think I'm missing the point, leaving a CKD hyperthyroid cat marginally hyperthyroid may be accepted practice but it is very much a compromise and IMO doesn't address the real problem - lack of fuids. Thyroxine is not treating renal disease, the only reason the CKD cat with hyperthyroidism is apparently doing better (in the short term) is because of increased perfusion due to hypertension which ulitmately will be more harmful. I re-iterate it makes no sense to iatrogenically raise BP then control it again with an anti-hypertensive. Indeed ACEi's work by reducing intra-glomerular pressure to prevent further glomerular damage, it is insane to deliberately increase it. It makes far more sense just to provide extra fluids to increase perfusion and prevent dehydration. Most CKD cats live in a state of partial dehydration even if they are polydypsic which leads to accelerated azotaemia. Other aids like anabolic steroids and appetite stimulants are beneficial but they are not working by improving renal function. Fluids, fluids, fluids my boy.

Re: Renal disease and thyroids

Julian Earl — Wed, 27 Jul 2011 10:49:39 GMT

[quote user="Martin Atkinson"]

I can see the logic but it is a bit of a loony idea Julian. The first rule of treating you patient is not to make it worse so creating iatrogenic disease by unconventional treatment is not the wisest way forward, you could be on sticky ground. As I'm sure you know, the reason hyperthyroid cats with CKD have their kidney disease masked is because of increased renal perfusion due hypertension. Ultimately hypertension will worsen the kidney problem due to glomerular damage and cause a host of other problems not least heart and retinal disease. So by making the euthyroid cat slightly hyperthyroid you are causing iatrogenic hypertension and are obviously aware of this by suggesting monitoring/treating blood pressure but if you're treating that then what's the point? Far more logical to treat the renal disease with conventional means (diet, ACEi, phosphate binders etc) and supplement with fluids at home via a skin button to maintain renal perfusion as it is relative dehydration that is the biggest enemy in cats with renal failure.

[/quote]

You're slightly missing my point. I am suggesting treating at such a low level that perfusion is increased but outright hyperthyroidism is not a clinical problem, if that is possible. Simply, if an marginally elevated T4 level is beneficial in a cat with natural hyperthyroidism, why should it not be in renal disease on its own? It may be possible to titrate the dose such that benefits occur without significant adverse effects. Maybe it is a good idea to improve perfusion yet lower overall BP with amlopidine to get the best of both worlds? I don't know but if increasing perfusion this way improves renal function then perhaps minor tachycardia, minor BP elevation, slightly increased metabolic rate are worth it?

We treat atopy with steroids after all and those are not a case of "doing no harm", other management options notwithstanding.

Yours sincerely,

The loony.

Re: Renal disease and thyroids

Richard Carter — Wed, 27 Jul 2011 10:41:54 GMT

Quick patent it and sell for vast amounts - sounds similar to using nandrolone in renal cases - keeps them eating, promotes protein mass and if I remember correctly from a previous boss, has a positive effect on bone calcium. Whatever the reasons, I have seen CRF cats exist for years using this technique even though the experts place doubt and prefer periactin and similar. Have also heard of people using ovarid for the polyphagia effect to keep them eating

Re: Renal disease and thyroids

Martin Atkinson — Wed, 27 Jul 2011 09:13:22 GMT

I can see the logic but it is a bit of a loony idea Julian.The first rule of treating you patient is not to make it worse so creating iatrogenic disease by unconventional treatment is not the wisest way forward, you could be on sticky ground. As I'm sure you know, the reason hyperthyroid cats with CKD have their kidney disease masked is because of increased renal perfusion due hypertension. Ultimately hypertension will worsen the kidney problem due to glomerular damage and cause a host of other problems not least heart and retinal disease. So by making the euthyroid cat slightly hyperthyroid you are causing iatrogenic hypertension and are obviously aware of this by suggesting monitoring/treating blood pressure but if you're treating that then what's the point? Far more logical to treat the renal disease with conventional means (diet, ACEi, phosphate binders etc) and supplement with fluids at home via a skin button to maintain renal perfusion as it is relative dehydration that is the biggest enemy in cats with renal failure.