Hi Customer (name blocked for privacy),
Kidney failure, unfortunately, is very common in older cats. It is not a curable disease, and eventually the kitty will succumb to it. It is treatable, in that the symptoms of it can be alleviated with certain treatments. Cats in kidney failure are usually put on a low protein diet, are sometimes on phosphate binders, and are often given subcutaneous fluids (IV fluids given under the skin with a needle) at home by the owner, on an every other day basis. All of these things are generally designed to keep the kitty feeling well, even though they are not really stopping progression of the disease. Many cats with hyperthyroidism have kidney disease as well, and it only becomes apparent once the hyperthyroidism is successfully controlled. The reason is that the state of being hyperthyroid, porduces a higher flushing of toxins through the kidneys and drives certain kidney parameters in the blood down (makes the BUN and Cr lower). These lowered BUN and CR can make the cat feel better. However, it does so at the expense of then having uncontrolled hyperthyroidism (which has its own negative side effects). So, I am not so sure that I agree with your vet's decision to stop treating the hyperthyroidism. This will not "stop or reverse the failure", it will just cover it up a bit...and then she will be suffering from two problems.
I am attaching some client information handouts that I use in my practice that discuss both of these conditions in more detail. I hope that you find them useful.
Click HereClick Here 2 You may want to consider asking your vet for a referral to see a specialist in veterinary internal medicine in your area. Most specialists are located at referral centers or colleges of veterinary medicine. The benefit of seeing a specialist, is that you are more likely to get a quick and accurate diagnosis of your animal's problem. It is also more likely that a specialist has seen this problem before and treated it successfully. I think that this would be a wise thing to do before stopping the treatment for the hyyperthyroidism.
I hope that this information is of help to you, and I wish you the best of luck with your kitty. Please let me know if I can be of further assistance.
Dr. K
If you found my answer helpful, please remember to click on the ACCEPT button, as this is how I am compensated by the website for my work. Please keep in mind that my on-line advice cannot take the place of a physical examination by a veterinarian.