In older cats, as in older people, a variety of health
problems become more common than they are in younger cats and kittens. This
week’s article will point out several things to watch for in your cat as they
become older.
First, how old is your cat, really? The system of assigning
7 cat years for each 1 year on our calendar is no longer considered accurate.
The best way to calculate your cat’s age in human years is as follows: the
first year of their life counts for 15 human years, then second year counts for
9 human years, and every year after that counts for 4 human years. So, for
example, a 16 year old kitty is: 15 + 9 + (14 more years at 4 years each) = 80
in human years. The previous system would assign your kitty an age of 16 x 7 =
112. So your old girl or old boy is a lot younger than you thought!
Nevertheless, as cats approach and pass the age of 10,
various problems start popping up more frequently than in younger cats. Three
of the most important are discussed below.
Kidney Disease
Perhaps the most common medical problem faced by cats as
they age is the onset of kidney failure. The kidneys make important hormones
for the body, clean the blood, and determine how much water to keep in or
filter out of the body. As a cat’s kidneys begin to fail—usually due to nothing
other than age—they begin producing excess urine. The litter box for these cats
will often be noticeably soaked. Cats typically do not drink much water; they
will begin drinking more and more to keep up with the urinary water loss. Some
cats begin to lose weight, eat less, and generally slow down. Of course, older
cats often enjoy a relaxed pace of living anyway, so the slowing down may not
be obvious. Simple blood and urine tests will help diagnose this condition.
If
an otherwise healthy-appearing cat is determined to be in the early stages of
kidney failure, usually all that is recommended is a change in diet to a
particular food designed for this condition, and the use of a medication called
Calcitriol that helps protect the kidneys from further damage and helps cats
feel better. As cats progress with this problem other medications may be
helpful. Studies show that older cats diagnosed in kidney failure live an
average of 277 days (about 9 months) when fed the proper food, yet live an
average of 736 days (over 2 years) when given Calcitriol as well.
Hyperthyroidism
The thyroid gland is a small gland in the neck covered by
the muscles adjacent to the larynx (“voice box”). This gland makes a hormone,
tetraiodothyronine — otherwise just referred to as the “thyroid hormone” or as
“T4”. In simple terms, this hormone sets the speed of one’s metabolism. The more
hormone produced, the higher the metabolic rate. In cats whose thyroid gland
becomes hyperactive, their metabolism speeds up. Those cats often have a high
heart rate, dilated pupils, eat voraciously, and actually seem unusually hyper
for an older cat. Most cats with this condition experience dramatic weight loss
despite eating more because their metabolism is running so fast they burn up
all the calories they eat, plus some.
However, about 25% of hyperthyroid cats feel bad from the
condition and become listless and inappetant. As with kidney failure, a simple
blood test can determine if a cat is hyperthyroid. This condition can be treated
either with oral medication given once or twice a day at home, or by receiving
an injection of radioactive iodine which returns the thyroid gland to its
normal rate of hormone production. In some instances surgery on the thyroid
gland is appropriate.
Cancer
Sadly, cancer is as common in our companion animals as it is
in humans. Cancer can strike any organ or body part, and when it occurs
internally there are often no indications while in the early stages. A general
decline in vitality may be all that is noticed, including a drop in appetite
and activity level. Sometimes it is necessary to take X-rays, perform an
ultrasound exam, perform endoscopy or laparoscopy (look inside with small
fiberoptic scopes) or do blood tests to determine if cancer is present.
Some
cancerous conditions can be effectively managed with minimal medications (e.g.,
bladder tumors or lymphoma—a kind of cancer of the lymph nodes and blood
cells), although other types of cancer require surgery or may not be treatable
in any case. The decision to treat or not treat a cat with cancer can be a
difficult one, and no single answer is right for all cats and all
families.
At our practice we recommend any cat over 10 years old have
a physical exam yearly, regardless of whether they are due for any
immunizations and even if they never leave the house. Often, a general
screening set of blood and urine tests is done to determine what a particular
cat’s baseline levels are for the various tests so there is a reference point
for future test results that may become abnormal.
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