I get this question a lot. An observant, concerned owner will walk into our clinic and ask "Why is my senior kitty losing weight?" So, where do we start with a cat that is losing weight?
We first need to get a clearer picture of the cat's home life by asking for some insightful information. The first question we need to answer is whether the cat has a good appetite or not.
A cat that has a reduced appetite is losing weight because she is not eating. The reduced
appetite can be caused by mouth pain resulting from dental disease or mouth tumors. It can also
be caused by kidney disease which in not uncommon in older cats.
On the other hand a cat that is eating well and still losing weight is likely to have either a disease
that is causing a higher than normal metabolic rate, or a disease that prevents her from absorbing
the nutrients into her body from the food that she's eating.
An increased metabolic rate, means that even though the cat is eating an amount of food that
should be sufficient for her weight and age, her body is acting like a furnace, consuming everything that she eats and then some. Most likely, this kind of behavior is linked to a disease called Hyperthyroidism.
Another possible scenario is that the cat is eating, but her intestines are not absorbing the food that
she is eating. That is caused by inflammation or tumor of the intestines. Inflammation means that
the intestinal wall gets thick and it's cells are not able to absorb the food. But, the good news is, inflammation, in many cases, is reversible. What that means is that we can treat it with special prescription diets and also with medications, especially at the initial stage of treatment. Tumors on the other hand usually require chemotherapy and will not respond to diet changes alone or even to
medications on the long term.
After obtaining a thorough history. Next, we examine the cat, and assess whether there is muscle mass loss and to what degree. During the exam we will also check if there is any thing physically noticeable on the cat that could explain the muscle mass to the extent that is observed.
Then we run a blood test to get more information on intestinal function like the degree of muscle break down, thyroid hormone levels, long standing mouth disease, kidney function all of which as
mentioned before could be contributing to the weight loss.
At that point some cats will have a slam dunk diagnosis as to what is causing their weight loss and
also what medications can be used to treat it. Others will have many diseases ruled out but still
will have more than one possible for what is seen on the physical examination and the lab work
and will need imaging or further lab work specific to the problems shown on the general blood
panel. It varies on what we find in the preliminary diagnostics.
Another approach is to try a short course of treatment of the most common disease of the
narrowed list and monitor the response. The draw back of this approach is that if kitty starts
showing signs that were not apparent before it becomes hard to tell if this is due to the normal
progression of the disease that has not been pin-pointed or due to a side effect of the treatment.
Also some treatments interfere with further testing.
So, to summarize, weight loss in senior cats can occur for a number of reasons and isn't as cut and dry as it may seem. It may take a few diagnostic tests to figure out exactly what underlying conditions may be present.