Ron Hines DVM PhD 4/29/06

Good nutrition and modern medicine are allowing cats to live longer and longer. Only thirty years ago cats usually went outside unsupervised. This led to a large number of car accidents that claimed their lives. Cat Distemper historically also claimed the lives of many cats. But it too has become rare in the United States and Western Europe over the last thirty years. The National Research Counsel’s 1960 study of feline nutrition and more recent studies identifying taurine as an essential nutrient for cats have all but eliminated nutritional diseases in cats fed commercial diets. So within the last fifteen years I have seen more and more oldster cats over the age of twelve.

Despite advances in medicine and nutrition, the primary determinant now as to how long cats live is genetic. Just like people, some cats inherit genes that allow them to live longer lives than others.. It is often say that one year to a cat equals seven years to a human being. Actually a one-year-old cat is similar to a young adult human – about 17 years of age. A two-year-old cat is physically equivalent to a 24-year-old human. After this, cat years drop in relation to human years so that by ten years of age a cat is equivalent to a fifty-year-old person. By the time a cat reaches fifteen years of age it is about equivalent to a seventy three-year-old person. My oldest feline patient was twenty-two years old and equivalent to about a hundred and four year old man.

Remember that aging in itself is not a disease. Many physical and physiological changes occur as cats age. Scientists believe that aging is the end result of all hurtful random events that accumulate in the body over time. There are several theories as to the exact nature of aging. I believe that the cause of aging is a combination of all four theories. The first thing that we know occurs as our cats age is an increase in cross-links in body proteins. These unnecessary bonds decrease the mobility and elasticity of proteins and other body molecules. Cross linkage of protein collagen is at least partially responsible for the cataracts we see in old cats as well as thinning of the skin. The wear and tear of time is also thought to damage the DNA of mitochondria, cells, tissues and organs. Eventually the body runs out of ability to repair this damage. Free radicals are toxic byproducts of cellular metabolism. Natural chemicals called antioxidants bind and destroy these dangerous compounds. Free radicals cause cross-linkage errors in proteins as well as DNA and mitochondrial damage. These errors in cells are called oxidative damage and the damage accumulates over time. Spontaneous changes or mutations of the genes of our cells also play a roll in age-related decline.

We have not yet found a way to reverse the process of aging but we can delay it in many ways. We can also control and modify many of the diseases that accompany aging to give your cat the happiest, healthiest and longest life possible.

Specific Problems

Arthritis:
Older cats often have mobility problems due to arthritis and degenerative joint disease. This makes it difficult for them to play and interact as energetically as they did when they were young. Only a few become noticeably lame but they do walk more gingerly and have trouble jumping up on couches, climbing stairs and getting in and out of the litter box. Unfortunately cats do not tolerate newer non-steroidal anti-inflammatory drugs such as carprofen (Rimadyl) well. Some cats can take aspirin at 5-10mg/pound but it must be given every second or, better yet, every third day. They do do well on glucosamine and shark cartilage products and on injectable Adequan. When arthritic problems become severe enough to make them miserable I place them on a carefull plan of treatment with intermittent prednisone or prednisolone and dietary weight control.

Nutritional Problems:
I have noticed that geriatric cats seem to have lost much of their sense of smell. Because of this, they often become picky eaters. The problem is that the things that they like to eat – such as canned tuna - rarely add up to a nutritious blend of nutrients. The intestinal tracts of these older cats are probably not as efficient in absorbing nutrients as they once were. Old cats have no problems absorbing fats however so many of them are quite plump. Fat cats are at a high risk of developing diabetes so I suggest to my clients that they restrict the amounts of food fed. Throughout their lives, I suggest to all my clients that their cats be given a vitamin E, C and B-1 supplement. Vitamin E and C are antioxidants that may scavenge free radicals. Many fish contain thiaminase that destroys vitamin B-1. The three vitamins are not toxic. I give one hundred units of E and C and one milligram of thiamin (B-1). An omega-3 and omega-6 fatty acid supplement is also a good idea. Omega fatty acids play an important role as structural membrane lipids, particularly in nerve tissue and the retina and are precursors to eicosanoids - highly reactive substances such as prostaglandins and leukotrienes that act locally to influence a wide range of functions in cells and tissues. I have also noticed that that cats that eat a diet that is primarily fish or fish flavored do not live as long as other cats. I believe this is due to free radical generating rancid polyunsaturated oils present in animal-quality fish products.

Dehydration:
Older cats are more prone to dehydration due to stress, hot weather or the fatigue associated with common diseases of older cats such as failing kidneys and thyroid disease. Old cats are also often poor drinkers even when water is available. I suggest several bowels of water in different areas of the house.

Poor Grooming:
Older cats often do not groom themselves as well as they did when they were young. This is due to arthritis, dental problems and general debility. They need your help with a weekly bath and daily combing with a soft slicker brush. Brushing removes the loose hair that gets swallowed and causes hairballs and constipation. It also stimulates circulation and oil secretion leading to a healthier coat. Clipping longhaired cats twice a year is another good way to handle this problem.

Brittle Claws:
The claws of older cats are often brittle and overgrown due to lack of scratching activity and changes in the nail bred.. I have seen them overgrow to the extent that they penetrate the footpad causing a painful ulcer. A human fingernail clipper and emery board can correct this problem.

Dental Problems:
Almost one hundred percent of the old cats I see have serious dental disease. Although few have cavities most have lost much of the gum that surrounds the base of the teeth as well as heavy accumulations of tartar. You can prevent this problem by starting to brush your cats teeth when it is a kitten and by feeding diets that are marketed to keep cat’s teeth clean,. This is more than a case of simple hygiene; infections that surround the teeth quite commonly move to the kidneys and heart valves.

Cognitive Problems:
It is hard to decide whether cats develop senility as people do or if the lack of response in old cats is just a sign of debility and hearing loss.. But I have examined old cats that were brought to me because of aimless wandering around the house, increased meowing and loss of interest in their owners that apparently had Alzheimers-like syndromes. These cats often do well when given selegiline (Anipryl) a drug approved to treat Canine Cognitive Dysfunction Syndrome (senility) in dogs.

Loss of kidney function:
Kidney function in older cats is never as efficient as it was when they were young. As cats age there is a slow but steady decrease in the weight of the kidneys and loss of filtering ability. Cats are born with a certain number of filtering apparatus in their kidneys. These filter apparatus are called glomeruli or nephrons and are lost because the walls of the blood vessels that form them thicken and become blocked as cats age. Cats are born with extra reserves of glomeruli but eventually not enough are functional and wastes begin to build up in the cat’s blood. This is called uremia. Many older cats are borderline uremic. Any stress that causes them to drink less will put these cats into a full blown uremic state.

Hyperthyroidism:
An over active thyroid gland is quite common in older cats. This problem leads to high blood pressure, excessive thirst, weight loss and heart irregularities. Cats with this problem are best treated with radioactive iodine to destroy abnormal thyroid tissue but they can also be managed with a medication called methimazole (Tapazole). For more information on this condition read my article on hyperthyroidism in cats.

Cancers, diabetes and inflammatory bowel disease all become more prevalent in cats as they age. You will find articles on these conditions at this website.

Loss of litter box training:
Arthritis makes it painful for cats to get into litter boxes with high walls. Diseases such as loss of kidney function, hyperthyroidism and diabetes all make cats produce more urine than normal leading to stinky litter boxes and soiling accidents. Decreased cognitive function and the frailty of old age also makes accidents more likely.

Decreased ability to handle stress:rontology
Aging results in a diminished ability to handle stress, maintain body homeostasis and regulate body systems. For example, old cats are more vulnerable to hypothermia when it is very cold or hyperthermia (heat stroke) when it is very hot outside because they are unable to compensate as effectively by regulating their body temperature.

What can I do to help?

It is wise to examine older cats weekly for signs of physical problems. I check their posterior for signs of urinary or bowel problems. Clipping the hair that surrounds their rear helps keep longhaired cats sanitary. Examine the cats mouth for tooth and gum problems as well as new growths that may be present. Check the ear canals for musty odor and exudate. As you brush the cat you can look for any new growths on the body. Growths on cats are more serious than on dogs because more of them are malignant. Your veterinarian should promptly remove them all.

It is important that you encourage your older cat to exercise and play. Older cats are less agile than they once were due to muscle atrophy and arthritis. Regularly playing with your cat helps retain muscle mass and increases tone and circulation. Regulate the amount you feed them so that they do not get too fat.

Since old cats do not handle stress as well as when they were young. It is wise not to leave them at boarding facilities and they may not appreciate new younger cats brought into the household.
When you must leave an older cat alone it is best if they remain at home cared for by a pet sitter or friend.

I suggest older cats have a check up and blood chemical analysis every year or two to determine how its body organs are holding up. Besides this, bring your cat in to a veterinarian if you notice a sudden loss of weight, growths on the body or changes in its drinking, eating or elimination habits. It is unusual for an old cat to change old habits – so be suspicious of changes instigated by your pet and be sure they are not health related. Enjoy your time together on this Earth – it passes all to quickly.

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