Gazette Vet: The Old Cat


By John Andersen, DVM

Whit and Lucy
Whit and Lucy

Our cat Lucy is an old cat.  Sixteen years ago, she was found as a tiny kitten, frolicking in the grass next to Duck Pond Drive in Blacksburg, Virginia. I didn’t know a thing about cats back then, but my girlfriend (now wife) convinced me to adopt her and the rest is history.  She has been a great cat and fortunately is still going strong.

But she has indeed aged. There are some changes that are definitely just age–sleeping more, vocalizing more, getting cranky if we’re not going to bed on time or getting up when we’re supposed to. But there had been some other changes over the years that were signs of problems and as a veterinarian I have come to realize that signs of old age diseases in cats are often very hard to differentiate from just regular “old age.”

In fact, sadly, I often will see old cats brought in for a problem only to find they are very late in the disease process. These cats had been declining under the radar for months to years, but only when something more dramatic happened did the owners realize a true problem was present. Unfortunately for some of these cats, they are too far gone to help significantly.

But it’s not as if these are terrible pet owners. Cats have a way of acting perfectly normal despite having some major health problems. Pretty much on a daily basis, I will see cats with organ failure, cancer, infections, and rotten teeth who are acting quite normal at home. Like dogs, cats are not programmed to show weakness. In fact, although cats are predators, they are also a prey animal, and as such it is probably hard-wired in them not to walk around looking weak and vulnerable.

Lucy has dealt with several of the most common “old cat” diseases, and I feel fortunate that we were able to notice these problems early on and manage them. Because of this, she is living large at 16 and really enjoying a good quality of life.  Below are a few of the old cat problems she has been diagnosed with and how we have managed them.

Chronic kidney disease. This is the most common old age disease in cats, a slow degeneration in kidney function. The kidneys do many things in the body, but specifically help to conserve water, eliminate certain toxins, balance minerals and electrolytes, and help keep our red blood cell counts normal. Kidney failure tends to have a slow progression, but in its late stages is lethal.

Years ago, we noticed that Lucy was drinking more and urinating more. That was it – she was otherwise eating fine and acting completely normal. But, both of her owners being veterinarians, we brought her in and did some blood work and sure enough, she had some mild kidney disease present.

The kidneys are an incredibly resilient organ. We can donate one of our kidneys, taking ourselves from 100 percent function to 50 percent function, and we’re fine. It’s not until we’ve lost around 66 to 75 percent of our total kidney function that things seem to go wrong, and the first of those is typically the inability to concentrate urine. So Lucy started drinking more, simply because she was losing more water and she was just trying to keep up.

Unfortunately, there is no cure for kidney disease, however there are some things we can do to manage this disease effectively.  For Lucy, we simply switched her over to 100 percent canned food, and we add some water to each meal. This is a simple, but powerful way to maintain her hydration. Dry cat food has about 5 percent moisture.  Canned cat food has 75 percent moisture, and we are adding water to that. Keeping your cats well hydrated is one of the most important management solutions in my opinion and fortunately for us, it has helped keep Lucy’s kidney disease stable all these years.

For cats with worse kidney disease where the kidney values are high or electrolytes are imbalanced, things get more complicated. These cats sometimes need potassium supplementation, phosphate binders, or other special diet changes. But in the end, it is useful to know if your old cat has kidney disease so you can make changes that are needed and with not too much effort, increase your time together.

Hyperthyroidism.  About 6 years ago, we noticed that Lucy was finishing all of her food a bit quicker than normal, and that she was doing this while also looking a bit thinner. She was otherwise acting completely normal. But again, the paranoid veterinarian owners knew: you shouldn’t be losing weight if you’re eating well. So we brought her in and checked her blood work and diagnosed Lucy with hyperthyroidism.

Hyperthyroidism is another very common disease in older cats. These cats get a benign nodule on their thyroid gland that secretes excessive levels of thyroid hormone. Thyroid hormone controls our metabolism, so when the thyroid levels are high, we see these cats start to waste away, despite eating a lot initially. Cats with hyperthyroidism tend to lose weight, have increased vomiting or diarrhea, and often are more active, even to the point of being “amped up” or annoying with nighttime vocalization, etc. If left untreated, hyperthyroid cats can lose incredible amounts of body weight, suffer from extreme high blood pressure, and often ultimately succumb to strokes and/or heart disease.

There are several ways of treating hyperthyroidism. The gold standard is an injection of radioactive iodine therapy.  This is simply giving them a small injection of radioactive iodine that gets concentrated in the thyroid gland and effectively zaps the abnormal thyroid tissue, sparing the rest of the body from any side effects.  It is very effective and safe, however is fairly expensive and has to be done at special “Radiocat” centers, the closest being Richmond.

Probably the most common treatment method used though, is methimazole, an oral or transdermal medication that helps stop the creation of new thyroid hormone. Last, there is a newer prescription diet that has come out that has zero iodine in it and if fed as the only thing that these cats get, their thyroid levels will often drop back to normal.

Because Lucy was only 10 at the time and was otherwise in pretty good shape, we invested in the radioactive iodine treatment. It was a great decision, as we have not had to give any pills in six years or deal with the side effects of a medication.

These two diseases are definitely the most common things we see in older cats and they do not have any major clinical signs when they start to become significant. Watch old cats closely. If they seem to be losing weight, drinking more, vomiting more, or changing in any way, bring them to your vet. We usually need to do some blood work because many of these diseases you cannot diagnose with a physical exam alone. Catching problems early usually makes dealing with them much easier and less expensive in the long run. Now, go spoil your old cat!


Please enter your comment!
Please enter your name here