Shannon

Hi,

I am in a panic. I am reading where the I-131 can cause kidney problems but also that the medicine Shannon is on for her heart can induce kidney problems by lowering blood pressure. Shannon is on Atenolol. Does anyone have any experience with this medicine with regard to kidney problems? I'm afraid I am watching my cat die. I have tried to contact the vet but they willnot take Shannon off Atenolol until her murmur is gone from the hyperthyroid problem. Please, can anyone help?

First, I-131 does not cause kidney problems. Hyperthyroidism can mask existing kidney failure. The kidney failure is present regardless of whether hyperthyroidism is treated or not--the increased blood pressure that hyperT causes forces the kidneys to work harder. As a result, the blood tests might show that BUN and creatinine are normal, even though the kidneys are insufficient.

Hyperthyroidism can cause heart problems or worsen an existing heart problem. That is why your vet is using Atenolol to treat Shannon's current heart problems. He's trying to protect her heart from futher damage. The high blood pressure can damage the kidneys over time as well as damaging the heart.

Treating with I-131 will almost always destroy the tumor that's causing hyperthyroidism (medication can help control the levels for a while, but the tumor will continue to grow). The kidney values may go up, but that's expected and reflects their true state, not a side effect of the treatment. Also, kidney failure can be managed. If your cat's kidney values are already high, you can talk to your vet about medications and treatments, like phosphorus binders, calcitriol, and eventually fluids. Heart disease is often silent, but it can be very deadly--I know as it was what took my Spot. Untreated hyperthyroidism can also make the cat feel really crummy--there were times when Spot looked like he was at death's door but he came through. I-131 is most effective when done as early as possible in the course of the disease. The longer you wait, the more likely the tumor will have grown to a point where the I-131 can't kill it. I know of many cats who had mild CRF and I-131. Most are in their late teens or early twenties and are still going strong.

I just looked back and saw that your Shannon has already had I-131. Again, it did not damage her kidneys. Her kidneys were already insufficient, and treating the hyperthyroidism just allows you to see that. What is her phosphorus level? You can talk to your vet about calcitriol--it apparently works wonders in helping kitties feel better. http://www.felinecrf.org/treatments.htm#calcitriol

What are her current symptoms? Her levels don't sound all that high, but it's how she's feeling that is important. How is her potassium level? It should be in the middle of the normal range or greater (for example, if the range is 3.5 to 5.5, it should be around 4.5 or higher). If it's low, you can talk to your vet about supplementing it--I've been told that the generic potassium gluconate from Target works really well and is easy to give.