Diagnosing Illness in Older Cats

Older cats can develop a myriad of illnesses. It's important to know about some of the signs and symptoms that may indicate illness. This article will discuss some of the more common illnesses in older cats including arthritis, hyperthyroidism, mouth tumors, and immune system weakness.


As a cat ages, his joints and muscles may begin to stiffen and become inflamed. He may be less able to run or jump up onto high places. His gait may appear stiff and limited. A vet can determine arthritic symptoms by checking range of motion and inflammation in the joints. Arthritis can be greatly decreased through a natural, whole foods diet as well as supplements including glucosamine and chondroitin.


Hyperthyroidism is a condition in which the thyroid gland produces excess hormones. Most cats develop this disease after the age of 13. The first signs most often include unexplained weight loss along with increased food and water consumption. The main danger with hyperthyroidism involves the increase in heart rate. This can manifest in increased activity, nervousness or other behavior changes. The rapid heart rate affects many systems in the cats body. The heart may become enlarged, leading to heart failure and death.

Diagnosing Hyperthyroidism

There are several ways that a vet can confirm the diagnosis of this disease. The first step is to report the changes in behavior and appearance. Then the vet can do a physical exam and feel the enlarged thyroid gland. A blood or urine test will also confirm abnormally high levels of T4. This is more of an indicator than higher levels of T3.

Cat Mouth Sores and Cancer

Cats can develop mouth sores that are either benign or cancerous tumors. These normally occur on the lip although in rare cases are present on the cornea. The tumor may cause inflammation in the face and may emit a foul odor. The cat may produce excess drool, and very foul smelling mucus and blood may come out from a visible tumor. Another sign of mouth cancer is when a tooth comes out more easily than expected. When it is cancer, the cat will often have difficulty eating or will stop eating altogether.

The cat may also sleep more than normal and may give you a look or make sounds that indicate that he is in pain and misery. To properly diagnose cancer, the vet will need to take a biopsy of the skin or tumor which may be too difficult a procedure for a very elderly or frail cat.

Immune System Changes In the Older Cat

A cat over 13 years of age responds differently to physical stress than a younger cat. As a cat's body begins to decline, the immune system becomes less able to fight off disease. Some cats develop an overall immune system disease which is referred to as feline AIDS, and the older cat's immune system may mimic that state.

If an elderly cat is already dealing with one illness and then catches a virus, he may be unable to fight off the virus and die as a result. Symptoms of immune system problems include viral symptoms that seem to just worsen versus improving with time. These symptoms can include runny or puss-filled eyes, breathing problems and weakness.