Mrs. Thompson was understandably concerned about her cat “Callie”. “Callie” is an 11 year old, strictly indoor cat that Mrs. Thompson brought in because she had noticed her drinking more water and also losing weight. Any time a cat owner brings a cat in for increased drinking, it is a significant clinical sign. Most cat owners only rarely even see their cat drink, unless the cat has trained them to turn on the faucet for a fresh drink of cold water. I asked if “Callie” had also been urinating more, but it was hard for the owner to tell since she had 3 other cats at home.
We hadn’t seen “Callie” for 3-4 years and she had definitely lost quite a bit of weight since then. Last time we saw her she was about 8 ½ pounds and now she was just slightly over 4 pounds. Although she seemed pretty bright and alert, I could tell she wasn’t her usual self because she let me examine her very well. On her last visit I had written she wouldn’t allow a thorough examination, which meant I quit before losing a chunk of skin. Besides the marked weight loss, the only other abnormalities seen on exam were bad breath and her kidneys palpated small.
In an older cat the three most likely causes of drinking more and drastic weight loss are diabetes, chronic kidney insufficiency, and high thyroid disease. I explained this to Mrs. Thompson and told her we would need to run some blood work to check for these conditions. She readily consented to these tests and within 15 minutes we had our diagnosis-“Callie” had chronic kidney insufficiency. When I was in veterinary school we called this chronic kidney failure, but describing it as insufficiency makes a lot more sense. While the kidneys continue to make urine, enough of the kidneys are diseased so that they can’t work well enough to keep the cat feeling well. Initially there is weight loss even though the cat’s appetite is good. The cause of this is diseased kidneys tend to leak proteins from the body leading to loss of muscle mass and weight loss. Then, toxins build up since they can no longer be eliminated by the kidneys. Usually this occurs gradually over months or even years until “suddenly” the cat starts acting sick.
At this point cats are very sick. As an example, “Callie’s” blood work showed extremely high kidney values. A normal BUN for a cat is up to 30. “Callie’s” BUN was higher than our chemistry machine could read which means it was over 180! A normal creatinine is up to 2.1. “Callie’s” was almost 6.0. At this point the only option for “Callie was to hospitalize her so we could administer intravenous fluids at a high rate to try to force these wastes out of the body through the diseased kidneys. Although this can’t fix the kidneys, we often can make the cat feel better and get them eating again for anywhere from a few days to a few months. Unfortunately, it is very hard to predict how cats will do until we try the fluid therapy. “Callie’s” owner agreed to try the therapy to see how she would do.
On “Callie’s” second day in the hospital, she was like a new cat. She was much more active and we started feeding her and she ate like crazy! We kept her on fluids another couple days and rechecked her blood work. Her BUN was now 77 and her creatinine was all the way down to 2.6! Both were still high but she felt well enough to eat. It is important to note that even with these elevated kidney values she was feeling much better. The goal on older cats should be to detect the kidney problems at this point before they are so sick.
This is one of the best examples of the importance of regular blood work on older pets. These values normally will increase gradually over months to even years. If we had recognized the problem prior to her getting so sick we could have significantly delayed the clinical signs of chronic kidney insufficiency. Studies have shown that if these rising kidney values are detected prior to onset of clinical signs, just by putting that cat on a diet specific for kidney disease can delay the onset of clinical signs by as much as 2 years! Talk to your veterinarian about testing your older pet before you notice problems for a longer, good quality life.
Chad Higgins, DVM has owned Amanda Animal Hospital for 14 years, caring for dogs, cats, ferrets, and other little furry critters.