The Geriatric Cat

Are pets living longer

Question: Dr. Richards,

Are pets in general these days living longer than they did 50 years ago? Some people say that the advent of immunizations for diseases such as distemper, parvo and heart worm have not prolonged the life expectancy of the average pet. But yet it also seems that geriatric medicine for pets has become more popular.

Tony A.

Answer: Tony-

It is hard to come up with specific numbers for longevity in dogs and cats for any time period. However, I am absolutely certain that dogs and cats live longer in our practice than they used to. We have at the present time in our practice at least five cats who are over 22 years of age, whose age can be verified. In addition, we have had at least three or four dogs who have reached twenty years of age, although I don't think that we currently have a patient of this age in the practice. I know that these pets are much older than any I saw when I started in practice. I am disappointed when my cat patients don't live to at least 16 to 18 years of age or when my small canine patients don't live to be 16 years of age --- and even when our big canine patients don't make it to 15 or 16. When I started in practice these numbers were more like 12 to 14 for cats and small dogs and 10 for big dogs. So I can't supply an answer with scientific credibility but I can tell you that I sincerely believe that pets are living longer than they ever have, or at least than they have at any time during my lifespan (which is closing in on 50 years).

Mike Richards, DVM 7/16/2001

Yowling at night

Question: Dear Dr. Richards:

I have an l8 year-old male neutered cat who, for the past six months or so has prowled around the house from midnight on yowling at the top of his lungs. Sometimes it seems more of a wailing. He never does it during the day. What could this strange behavior mean? He seems otherwise in fairly good health for his age. He does have some arthritis as one might expect.

I would appreciate any insight into his behavior.

Thank you. Janice

Answer: Janice-

Night-time yowling is a very common problem in older cats. Like many symptoms, it has multiple causes. Many older cats have more than one of the listed problems, so it is important to carefully consider the possibility of all of them in an affected cat.

Hyperthyroidism is the most commonly reported inducer of this behavior and is also the most likely medical cause in a cat that is on the young side when the behavior occurs. This is relatively easy to test for but it can take more than one test, in some instances, to confirm the diagnosis. Usually cats with hyperthyroidism have increased activity levels and are eating more but not gaining weight.

Hypertension (high blood pressure), normally associated with kidney failure, can cause night time yowling. Or at least treatment for hypertension sometimes decreases night time yowling --- it is hard to be sure that the medication doesn't have a beneficial effect separate from the lowering of blood pressure unless accurate blood pressure monitoring is done.

Cats appear to be affected by decreases in their ability to see and to hear in a manner that induces yowling at night. There is a theory that this produces anxiety and that yowling is the result. Some cats do respond to anti-anxiety medications such as diazepam (Valium Rx) or amitriptyline (Elavil Rx).

Cats also seem to get cognitive disorders similar to those experienced by dogs and humans, in which confusion, loss of orientation and other signs of decreased mental ability occur. This may lead to night time yowling, as well. The currently recommended treatment for this is to try selegiline (Anipryl RX). This medication isn't approved for cats (but then neither are diazepam or amitriptyline) and there is less proof that a condition responsive to it exists in cats than there is in dogs.

Sometimes simple things like giving an antihistamine at night, deliberately keeping the cat up and active in the early evening and making sure food and water are easily available at night will help.

I have heard that older people sometimes experience difficulty sleeping at night that doesn't seem to be related to other problems. I think this might also occur in cats. It seems possible that this is sometimes just a complaint about not being able to sleep or a cat looking for a little comfort when it is bored at night and can't sleep. If this is the case I don't know what to suggest except maybe adopting a nocturnal pet to keep the cat company. Of course, that has lots of potential problems as a suggestion, too!

Ruling out hyperthyroidism and hypertension seem like the best first steps, to me. Hope this helps some.

Mike Richards, DVM 1/26/2000

Weight loss, older cat

Q: Dr. Mike-

My ten-year old cat has been losing weight for several months. She seems to feel fine except for the weight loss and labwork has all been normal, including a T4 value of 1.7 mcg/dl (normal 0.8 to 4.0 mcg/dl), normal glucose levels and normal kidney values. Is it possible that hyperthyroidism is the problem despite the normal blood values?

A: Linda-

As cats get older their T4 levels drop. Some older cats with T4 levels in the midrange or even in the lower half of the range for T4 are actually hyperthyroid because their individual "normal" value is very low. We have seen this problem mostly in cats that are 15 years or more of age.

Thyroid hormone levels can vary a lot over time in cats and some cats with hyperthyroidism can be detected simply by repeating the total T4 test at a later time. Usually it is best to wait at least a week and some endocrinologists recommend waiting a month.

It is possible to test for hyperthyroidism using more specific testing if it seems warranted. There are two ways to do this. One is to draw blood and test for free T4 levels (the free T4 is the portion of total T4 that is circulating in the blood system without being bound to anything). It is possible for the free T4 to be high while the total T4 is low. This test is also occasionally misleading because some other conditions, most notably kidney failure, can cause rises in the free T4 levels. An alternative test is T3 suppression testing. The test takes three days, on the first day blood is drawn and saved under refrigeration so it can be compared with blood drawn on the last day. Oral T3 (Cytomel Rx) is administered every 8 hours for 2 days and the morning the of the third day. Then blood is drawn again within 8 hours of this pill. The T4 levels in the two samples are compared. In cats with hyperthyroidism, the T4 level in the second sample should be below 20nmol/L.

Of course, there is also a strong possibility that your cat doesn't have hyperthyroidism, so it is important to evaluate the overall situation. If weight loss continues and can not be explained by other lab results or physical exam results then it would be a good idea to test for mild or hidden hyperthyroidism. Other signs that might indicate hyperthyroidism are increases in activity level, increases in vocalization, vomiting or regurgitating frequently, heart rate increases and sometimes other behavioral changes (increased aggression, changes in urinary habits such as an increase in marking behaviors) and sometimes increased drinking and urination.

There is not a great deal of risk in being patient and waiting for further developments if hyperthyroidism is present, so there is no strong need to eliminate the possibility through further testing in the absence of supporting clinical signs. I have been trying to figure out what percentage of older cats that we see with unexplained weight loss may have this problem and do not really have a firm idea at this time.

Dr. Mike Richards, DVM

Diet for older cat

Q: Hello Dr. Richards,

My Himalayan cat will be 10 years old this fall. Should I change or add to his diet due to his age? He's never had a problem with his weight, but is there a supplement he should get because of how old he is? His diet is primarily dry cat food and soft cat food for a "treat". The dry cat food has 27% protein, 8% fat, 3% fiber, 8.5% ash and 1.1% calcium. (It's a brand food from here in Germany).

Also, can you please send me the May digest again please? I usually print each monthly digest for reference and mistakenly forgot to print May's and no longer have it on my hard drive. I'd really appreciate it!

Thank you for your response! Carolyn

A: Carolyn-

I wouldn't change the diet of a 10 year old cat patient who did not show signs of problems. There are a lot of theories about changes in diet that might be necessary in older cats and dogs but there isn't a whole lot of solid evidence to back up the theories. Someday I might think differently but for right now, I think that it is OK to feed a diet that is sufficient for all life stages to older cats.

Mike Richards, DVM 6/10/99

Disorders in older cats

Q: Dear Dr Mike, We have a 17 year old neutered male cat called William, living in England. For the last 4 years he has been on Hills Science k/d and occasional cooked white fish. This was as a result of a blood test in 1995, showing high urea and creatinine. He has had mild facial twitches for 5 or more years and occasionally gets trembles on his upper body which come and go with no set pattern. He has been generally fine (but blood tests in Dec 1997 showed a raised bile acids to 9.3, ALT from 63 to 193 , and ALP from 47 to 84 ) up until about 3 months ago when he started to go off food - not completely but not really interested, and was lethargic in the day and very restless at night. He also has become stiff and wobbly on his back legs. Weight has dropped from 10lbs to 8lbs. He is not drinking or urinating more than he normally ever has done. He does sometimes appear to drift into a slightly dazed state. He was wormed with Bayer Drontal on 21/3/99 for roundworm and tapeworm. On 6th April 99 we had another blood test taken showing further raised ALT and Alkaline Phosphatase, but with no change in Urea or Creatinine levels. On 7th April 99 our vet gave Vit B12 and anabolic steroid injection which did not seem to help, but 2 or 3 days later he developed enteritis causing retching and diarrhoea, streaked with blood on one occasion. The vet treated this with a 5 day course of Synulox antibiotic and an anti-inflammatory which worked wonders. Within a day he was eating well and back to his old self of 6 months ago. However after 6 days he become dull and listless again, had lost his appetite (not completely) , bad trembles and bad breath. On 19th April he had another anabolic steroid and Vit B12 injection. From 19th to 22nd he ate reasonably with normal stools until 23rd when he did not eat and appear lethargic and wobbly. On evening of 23rd we took him to vet and he injected a dose of a different anti-biotic, and another anti-inflammatory and Vit B12. On 24th ate ok but bad trembles. On 25th did not eat and was slow, tired and restless. On 26th April he developed severe diarrhoea (bloody once) and drank a lot. This cleared up within 4 days - treated only with probiotic and homeopathic medicines. However, his appetite has not picked up, although he shows interest in food but does not eat it. Interestingly, today, 3rd May we gave him some commercial Whiskas Salmon and Trout that he ate well , although still tired. He is currently on some homeopathic medicine Lycopodium, Carduus and Chelodonium to help with liver disease. Please help! Is it liver or kidney problem ? What should we feed him? How should we treat him? Where do we go from here? Many Thanks Jackie and Chris

A: Jackie and Chris-

Older cats are prone to several disorders that could cause the labwork and the clinical signs that you are seeing.

Low serum potassium levels are commonly associated with renal insufficiency in older cats. Even though the kidney values are not worse in the new lab work compared to the older lab work, this problem can exist. The most recent lab values do not include serum potassium levels. Low serum potassium can cause muscular weakness, sometimes affecting on the rear legs but more commonly affecting the rear limbs and the neck, which is not held as high or which may even be hard for the cat to lift up to horizontal position. I think that it may be worth establishing that the serum potassium levels are still normal. Supplementing potassium seems to help with appetite, general well-being and muscular strength.

Hyperthyroidism can cause lethargy or restlessness. It is possible that you could see both signs in a cat at various times. It also can lead to disturbances in both kidney and liver values. The total serum T4 level is not a reliable indicator of hyperthyroidism in all cats. It has been our experience that the older a cat gets the lower its total T4 is, even if it is functionally hyperthyroid. A free T4 test done by the equilibrium dialysis method is more accurate in determining whether hyperthyroidism is present. If it is possible to palpate enlargement of the thyroid glands that is a significant finding, as well. We use the free T4 as a screening test and then to T3 suppression testing if we have any question about the validity of the free T4 test (it can be falsely elevated when kidney failure is present, so we might do a T3 suppression test if the free T4 is high but we can't feel enlarged thyroid glands, for instance).

Older cats may develop cholangiohepatitis, which is a chronic form of hepatitis. This condition is best diagnosed using liver biopsy but many vets are reluctant to do liver biopsies since good biopsies usually involve surgery or ultrasound guided needle biopsy techniques that are not available to a lot of general veterinary practices. It is sometimes responsive to corticosteroid administration and some practitioners use other medications, such as metronidazole, ursodeoxycholate, lactulose or other medications, as necessary, based on the biopsy results and clinical signs.

There is a condition that Dr. Hoskins has written an article about (DVM Newsmagazine, Feb 99) and called "triad syndrome" which usually has vomiting as a major clinical sign (you didn't mention vomiting) but which could produce the rest of the clinical signs seen. This is a combination of inflammatory bowel disease, chronic pancreatitis and chronic cholangiohepatitis that seem to occur together often enough to deserve being considered a syndrome affecting older cats. It is supposed to respond to roughly the same treatment except that Dr. Hoskins also recommends using potassium gluconate and l-carnitine when treating this syndrome.

I can't say for sure that any one of these conditions is actually present but I really would like to know the serum potassium level, free T4 value and to have a liver biopsy in addition to the tests already done in order to make a more definitive diagnosis if I had to make treatment decisions at this time.

Some of the signs you are seeing may be related to aging. There is some evidence (none really scientifically confirmed that I know of) that cats suffer from a similar cognitive dysfunction syndrome (senility syndrome) as has been recognized in dogs. If this is the case and the use of selegiline hydrochloride, also known as l-deprenyl or Anipryl (Rx) may be of benefit. This is a very long shot consideration, though. Especially with all the other clinical signs present.

A liver biopsy done during exploratory surgery would also allow the surgeon to look for liver cancer and to consider taking pancreas biopsy samples if that seems appropriate at the time. Vets are often really really reluctant to take pancreatic biopsy samples for fear of inciting pancreatitis but it seems to be safe to do this if the pancreas isn't handled too roughly.

Hope this helps.

Mike Richards, DVM 5/5/99

Weight Loss

Q: I have a neutered male cat, at least 14 years old, maybe older. He's the oldest cat in a household of six cats - all neutered males. He got his booster shots 3 weeks ago. For the last few years he has been getting thinner and thinner and is now frighteningly boney. His vet has checked his kidneys, thyroid, heart, and so on and doesn't find any irregularities. He was checked for aids about one or two years ago. His behavior is much like normal except he cries a little more and wants to be held a little more often. His fur is kind of oily and rough looking. He has a histamine producing growth in one eye that causes his eye to run and which has been removed once, but is recurring. I find no evidence of worms, or other problems. I am very concerned about his thinness, his vet says is just age, but I feel I must explore every possibility personally, although he doesn't seem in distress I feel a little more weight wouldn't hurt him. What conditions should be checked or rechecked? Is there anything I can do to help him gain a little weight. I've tried feeding him baby food, canned cat food and off my own plate in addition to his regular dry food (Science Diet, Feline Maintainence - always available). I feel I must explore other possibilities besides just his age causing this condition.

A: I would recheck the thyroid levels. I have been dismayed this year to discover three of my patients had hyperthyroidism even though they had normal thyroid levels. We have begun using the free T4 level to try to differentiate between these "apparently normal" and really normal cats. An alternative test is a T3 suppression test. Both of these tests help to distinguish older cats who are producing too much thyroid hormone for their own good but not enough to have high blood test results on a T4 test from normal cats. All of the signs you are seeing point towards this problem and I'd try really hard to be sure it is not the problem. We send our blood samples to Specialized Assays in Tennessee but I am pretty sure the Michigan State University endocrine lab also does free T4 testing in cats. If these test come out normal, too, I'd ask for referral to a veterinary teaching hospital or internal medicine specialist. It certainly seems like something is wrong and there are unfortunately a lot of other possibilities.

Checking carefully for metastasis of the eye tumor may be a good idea as well. Cancer is another problem in which weight loss is common.

In general, it is OK to feed older cats a higher fat diet to help support weight maintenance, providing it does not cause them to gain weight and become obese. K/D diet from Hill's is an example of a higher fat diet that could be used.

Good luck with this. Mike Richards, DVM

Odd behavior in elderly cat

Q: Our very old cat has these sudden fits and catapults herself off the sofa, often flipping herself over and ends up biting chunks of fur when she lands. Otherwise she sleeps most of the day and seems okay. Is this a hyperthyroid problem? She does yowl frequently for no apparent reason. She has a good diet and I've supplemented it with codliver oil but she seems to be deteriorating. Worse, I think I am developing a post nasal drip and an allergy to her because of all the danders and fur she stirs up in these fits. If it is hyperthyroid, does a blood test show it?

A: Offhand, I can't think of a reason for the behavior you describe -- but it wouldn't surprise me if hyperthyroidism did cause something similar to this. In most cases, hyperthyroidism is pretty straightforward to test for. High T4 levels in the blood are measurable. A few really old cats can have confusing blood values and require a little more specialized testing, though.

I do think this behavior warrants a physical exam by your vet. All sorts of stuff can cause odd behaviors and many of the problems are discernible just by physical exam or fairly routine labwork.

Good luck finding out what is wrong! Mike Richards, DVM

Older cat grooming

Q: We have 20 year old cat standard american cat. Long hair. lately her hair mats badly before we can brush or comb it out. is there any dietary additive we could use for this or what else can you suggest. also is there an "easy" painless way to get mats out. thanks for any suggestions you can make ? Ron

A: Ron - It is not unusual for older cats to stop grooming effectively and for mats to develop in their haircoat. Unfortunately, I do not know of a dietary additive or easy treatment. We use a mat rake to take out the mats because it seems to bother them less than a comb. Sometimes we have to shave or clip the mats out but not too often. Brushing daily or even several times a day may be necessary to prevent recurrences of the matting.

Michael Richards, DVM