Alternative hyperthyroid treatments

RE: Alternative hyperthyroid treatments

Julian Earl — Sat, 21 Nov 2020 13:15:55 GMT

[quote userid="12930" url="~/001/veterinary-clinical/small-animal/medicine/f/discussions/29507/alternative-hyperthyroid-treatments/226792#226792"] quite often just go straight to thyroidectomy. More often I give some felimazole first. In your case I would do thyroidectomy.[/quote]

My feelings as well. Okay I might be reaching dinosaur status nowadays but when we first started diagnosing these cases, many years ago now; as opposed to just seeing them of course!] I would always immediately go for thyroidectomy. I see it as a simple surgery with a highly positive outcome and cannot recall any subsequently returning with renal failure attributable to the surgery. Bearing in mind that I must have operated on over 100 hyperthyroid cats over the years, I feel that my suggestion to operate as first line therapy is justified? I hope this case proves successful for both you, and the cat!!

RE: Alternative hyperthyroid treatments

Lucy Fleming — Sat, 21 Nov 2020 11:46:15 GMT

[quote userid="8991" url="~/001/veterinary-clinical/small-animal/medicine/f/discussions/29507/alternative-hyperthyroid-treatments/226805#226805"]I've never seen hypothyroidism in a cat following thyroidectomy, not to say it isn't a thing, but how common is it following bilateral removal? [/quote]

The only information I can find is following I-131 treatment, and even then it was variable (seemed to depend on the dose of iodine given - high dose more likely to lead to hypothyroidism, but lower dose more likely to lead to treatment failure).

Logic would seem to dictate that bilateral removal should lead to hypothyroidism, but then ectopic tissue is thought to be relatively common (but again, I can't really find much data to back that up, I'm just remembering what I've been told which isn't very evidence based medicine!) Rare after unilateral I would have thought - maybe transiently post surgery, if some atrophy on the other side?

*Edited to add: found this small retrospective study of thyroidectomy cases, but haven't read more than the abstract yet!

researchonline.rvc.ac.uk/.../11952.pdf

RE: Alternative hyperthyroid treatments

Clive Ansell — Thu, 19 Nov 2020 12:33:44 GMT

I've got 3 old cats on y/d across 2 of my regular practices. it is working well for them and they are clinically stable and euthyroid on bloods.

Definitely worth a try?

18 years old cat - can't it just live out its life untreated?

I've operated on untreated hyperthyroid cats before, and find HR drops once anaesthetised, but can add in BB if needed.

Maybe one for triple/quad combo?

RE: Alternative hyperthyroid treatments

Anthony Dennison — Thu, 19 Nov 2020 09:05:59 GMT

[quote userid="5464" url="~/001/veterinary-clinical/small-animal/medicine/f/discussions/29507/alternative-hyperthyroid-treatments/226803#226803"]

y/d at least worth a go isn't it?

I've had two hypert4 cats myself. Neither of them would eat y/d. But I'd still try it first if I had another cat with hypert4, and sounds perfect for this case

[/quote]

Honestly? No. Out of all the cats we've ever tried to give y/d to, I think only one ate it. The control was so bad we eventually switched to oral medication.

I'm erring on the side of thyroidectomy. Worth using beta blockers to reduce the heart rate first?

RE: Alternative hyperthyroid treatments

Rob Loxley — Thu, 19 Nov 2020 08:48:40 GMT

Have seen a number with subnormal T4 but usually clinically insignificant, unless renal disease. Likewise with I-131

RE: Alternative hyperthyroid treatments

David Mills — Wed, 18 Nov 2020 09:56:56 GMT

I only do unilateral thyroidectomies. According to our figures it normally gives 18 months of disease free time and in about 40% is curative. It avoids parathyroid issues. Can always do the contralateral side if it decides to misbehave in future.

I've never seen hypothyroidism in a cat following thyroidectomy, not to say it isn't a thing, but how common is it following bilateral removal?

RE: Alternative hyperthyroid treatments

Chris Geddes — Wed, 18 Nov 2020 09:44:12 GMT

y/d at least worth a go isn't it?

I've had two hypert4 cats myself. Neither of them would eat y/d. But I'd still try it first if I had another cat with hypert4, and sounds perfect for this case

RE: Alternative hyperthyroid treatments

Rob Loxley — Wed, 18 Nov 2020 08:42:04 GMT

but you do want to avoid iatrogenic hypothyroidism (which can happen post thyroidectomy) due its negative consequences on the kidneys and survival

RE: Alternative hyperthyroid treatments

Lucy Fleming — Wed, 18 Nov 2020 08:40:27 GMT

[quote userid="8991" url="~/001/veterinary-clinical/small-animal/medicine/f/discussions/29507/alternative-hyperthyroid-treatments/226796#226796"]I think this theory has been shown to be false? Cats with renal disease have renal disease. The hypert4 doesn't alter that fact. I'm sure the RVC stuff showed that cats with insufficiently treated hypert4 had lower survival times than those with renal disease treated properly, and that the half and half stuff of dogma was shown to not do much[/quote]

Spot on - untreated hyperthyroidism is thought to actually contribute to progression of CKD due to glomerular hypertension. Conversely, you do want to avoid hypothyroidism as this can reduce glomerular filtration rate and contribute to azotaemia - could always supplement with thyroixine post surgery if needed (apparently TSH measurement is the most useful for detecting hypothyroidism)

RE: Alternative hyperthyroid treatments

Beats — Tue, 17 Nov 2020 22:13:55 GMT

If the urine is suspiciously dilute on cysto (say 1.020) then I'm more inclined to do unilateral thyroidecomty. May be wrong, but I think hypothyroidism may exacerbate kidney issues.

RE: Alternative hyperthyroid treatments

David Mills — Tue, 17 Nov 2020 21:27:35 GMT

I think this theory has been shown to be false? Cats with renal disease have renal disease. The hypert4 doesn't alter that fact. I'm sure the RVC stuff showed that cats with insufficiently treated hypert4 had lower survival times than those with renal disease treated properly, and that the half and half stuff of dogma was shown to not do much.

Hypert4 is a surgical disease if there's goitre.

Very rarely pre treat these days. When these cats are GAd they're more stable physiologically!

RE: Alternative hyperthyroid treatments

Rob Loxley — Tue, 17 Nov 2020 21:22:06 GMT

Just be sure of it’s renal function before a non reversible treatment

RE: Alternative hyperthyroid treatments

Beats — Tue, 17 Nov 2020 20:47:58 GMT

i quite often just go straight to thyroidectomy. More often I give some felimazole first. In your case I would do thyroidectomy.

In theory you could feed it hill's y/d if it still exists.