Case of the Week: Amadeus

For our case this week, we look at a trembling cat and learn what we discovered when we investigated this minor change in behavior.

Amadeus is a four-year-old domestic shorthair that has been coming to the clinic for two years. On his first visit, he weighed seventeen pounds and had a body score of 8/9. A body score of 5/9 is ideal and 9/9 is obese, so Amadeus was quite portly. We started him on a prescription diet food and he began losing weight well. He developed constipation but did well with a regular stool softener added to his food. Over two years, he eventually lost four pounds and decreased to a body score of 6/9.

In December, he came in for an exam before going off to college with his owner. She had noticed him trembling in the past few days and wanted to have him checked out before they left town. He also was not eating as well and seemed constipated again. When I examined him, I did not find any neurological problems or any other medical problems except that his colon was very full with stool. We gave him an enema, which was, to put it delicately, very successful.

We also ran a full blood panel to check his overall medical health. His blood counts and thyroid level were normal. However, his blood chemistry test showed that both of his kidney values were increased and his potassium level was a little low. Muscles need potassium to function well so the low potassium was likely the cause of Amadeus' trembling. The kidney values could have been elevated due to dehydration associated with the constipation or an indication of kidney disease. This would be unusual in such a young cat so we needed to do more tests.

A urine sample showed that Amadeus' kidneys were not concentrating his urine properly. Normally, cats have very high urine concentration, called specific gravity. Amadeus' urine was mildly concentrated but nowhere near what is normal for a cat.

We suspected something was wrong with his kidneys. We had Dr. Green, an internal medicine specialist, perform an ultrasound of Amadeus' abdomen at our clinic. He found stones in each of Amadeus' kidneys but the structure of the kidneys appeared normal. The stones could have formed because of early onset kidney disease or due to diet related factors. We do not typically remove kidney stones in cats because of the high rate of complications with the surgery and most cats do not pass the stones. A special diet and increasing fluid intake can be used to prevent the growth of the stones and help slow kidney decline.

We started Amadeus on a potassium supplement and a prescription urinary diet. We showed his owner how to give him fluids under the skin and she will give him fluids twice weekly. The trembling could also be due to discomfort from the stones. If it does not stop with the potassium supplement, we will see if pain medications help. We will need to examine him and check his blood levels regularly to monitor his kidneys and see if other medications are needed.

Although kidney disease occurs much more frequently in older cats, it can develop in young cats as well. Cats are very good at hiding symptoms and often owners do not know that there is a medical problem developing. Amadeus' owner was right to be worried about an apparently minor change in behavior. The sooner we diagnose kidney disease and other medical problems, the more we are able to do to treat the disease. We recommend that all cats be examined every six to twelve months by their veterinarian. A full blood panel should be done at least once after the cat's first year and then regularly starting at six or seven years of age.

Dr. Judy Karnia