It’s the little things: Small changes in behavior can signal health issues in your cat

Dr. Anna Dunton-Gallagher / Photo

Dr. Anna Dunton-Gallagher

As I start this article, it’s time to get something out in the open — cats are weird. Weird isn’t bad. I love my cat with all of my heart. Cats are more independent than dogs, so their illness typically presents in different ways, but that doesn’t make it less important. Recently my own cat was sick. I took her up to see a specialist, and when they asked what the signs were that she was sick, I told them the only thing that had changed — she slept in a different place than usual.

Clients are often reluctant to tell me these types of weird things. They think that if they bring their cat in for sleeping on the floor instead of the bed I’ll think they are crazy. While weird signs that seem to mean nothing may make it harder for me to pin down a problem, it doesn’t mean they aren’t important. As our cats age, there are many changes that we start to see. I will talk about these, but the important thing to remember is that every cat is different, and often with our feline friends, the small signs can mean big things.


Many older cats develop hyperthyroidism as they age. The most typical age of onset is about 12, but it can vary greatly among cats. We typically see an increase in appetite with a weight loss, vomiting, increased vocalization, increased drinking and urination, hyperactivity (especially at night.) Therefore, if your cat went from sleeping through the night to yowling at 4 a.m., it can be an indicator of hyperthyroidism. This seems like a detail you might not think is important, but it can tell us a lot.

Hyperthyroidism is caused by an overproduction of T4, the circulating thyroid hormone. This is easily diagnosed with a blood test and very effectively treated in most cats. Many times, on physical exam your veterinarian will see abnormalities that aid in the diagnosis as well. The treatment is a medication which simply lowers the T4 in the bloodstream. There is a specially formulated veterinary diet which can even regulate some cats without additional medication. Cats can also undergo a treatment to remove the thyroid gland surgically, or more commonly, with an injection of radioactive iodine. This must be done at an approved facility, but after one treatment cats will no longer need any medication! While it is more costly upfront due to the need for referral to a specialty clinic, many owners love the idea of not needing to ever treat their cat again. If you add up all of the medication for the rest of their life, this is usually more money upfront but not more in the long run.

When hyperthyroidism goes untreated, cats are prone to developing other problems. Heart problems and high blood pressure are the most common effects. Unfortunately, if the heart disease goes untreated, cats are more prone to developing life-threatening blood clots.


Cats can develop cardiomyopathy even without thyroid disease as they age, though increased thyroid is often a factor. In cats, we typically see hypertrophic cardiomyopathy, which means that the walls of the heart become very thick. Since they are too thick, a smaller amount of blood is held in the chambers and the heart pumps less effectively. Cardiomyopathy can lead to lung disease and blood clots. Blood clots can become lodged in vessels to the extremities, kidneys, or even in the aorta, which cuts off all blood flow to the rear legs. Cardiomyopathy can be managed, and the most effective management occurs when we are able to diagnose it early. While it cannot be cured, cats can live a much improved life with treatment. Many owners will never see signs of cardiomyopathy unless a blood clot causes an emergency. This is part of why a yearly physical exam is so important. Listening to the quality and speed of the heart helps us detect problems early and guide us to further diagnostics.


Many older cats develop diabetes, especially cats that were/are overweight. Diabetes in cats is very similar to Type II diabetes in humans. This is detected with a physical exam, blood glucose level and urine glucose level. In diabetes, we typically see weight loss with decreased appetite (though some cats eat more), greatly increased urination and thirst, and often peeing outside the litter box. Urinary tract infections are common in diabetic patients, as the bacteria thrive off the excess sugar in the urine. One of the things that owners tell us changes is that they go from cleaning a little bit of urine in the box to a lot, or seeing their cat drinking more.

Diabetes is treated easily with a simple diet change in many cats. Moving cats to a high-fiber, high-protein diet with low carbohydrates can cure many cats, and they can wean off insulin altogether. Some cats require daily insulin injections for life, but typically at a very low dose. Controlling diabetes helps protect the health of the pancreas, liver and bladder.

Kidney disease

A very high percentage of older cats suffer from some level of kidney insufficiency. This often starts being visible with increased urination. You may also notice differences in the urine and the cat’s hydration level. Kidney disease is progressive, which means that it will get worse with time. However, supplements, diet changes and at-home fluid therapy can help these cats live a longer and healthier life after diagnosis. New blood testing helps us identify kidney disease earlier, which is another reason that screening bloodwork can make a big difference.

You may have noticed that while these diseases are very common, most of them don’t have a dramatic symptom. Small changes build up over time. The more attuned you are to the small changes, the earlier and better we can treat your cat. While I went to an internal medicine specialist armed with a complaint of “sleeping on the floor and not the bed” we found a severe bladder infection and pancreatitis. I was able to treat my cat and get her on the path to health. Your cat isn’t necessarily going to fall over crying like my dramatic dogs do, but that doesn’t mean that little changes aren’t important.

Dr. Anna Dunton-Gallagher

Dr. Anna Dunton-Gallagher is a veterinarian at All Points Animal Care in Rutland. Have a question on this or any animal health topic? E-MAIL:

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