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Diabetes Mellitus in Cats
This disease is seen on a fairly regular
basis, usually in cats 5 years of age or older. Simply put, diabetes mellitus a failure of
the pancreas to regulate blood sugar. The pancreas is a small but vital organ that is
located near the stomach. It has two significant populations of cells. One group of cells
produces the enzymes necessary for proper digestion. The other group, called beta-cells,
produces the hormone called insulin.
In cats, two types of diabetes mellitus
have been discovered. Both types are similar in that there is a failure to regulate blood
sugar, but the basic mechanisms of disease differ somewhat between the two groups.
1. Type I, or Insulin Dependent Diabetes Mellitus,
results from total or near-complete destruction of the beta-cells. This is the most common
type of feline diabetes. As the name implies, cats with this type of diabetes require
insulin injections to stabilize blood sugar.
2. Type II, or Non-Insulin Dependent Diabetes Mellitus,
is different because some insulin-producing cells remain. However, the amount produced is
insufficient, there is a delayed response in secreting it, and the tissues of the cats
body are relatively resistant to it. These cats may be treated with an oral drug that
stimulates the remaining functional cells to produce or release insulin in an adequate
amount to normalize blood sugar. Alternatively, they may be treated with insulin. Cats
with NIDDM may ultimately progress to total beta-cell destruction and then require insulin
injections.
The role of insulin is much like that of a
gatekeeper: it stands at the surface of body cells and opens the door, allowing glucose to
leave the blood stream pass inside the cells. Glucose is a vital substance that provides
much of the energy needed for life, and it must work inside the cells. Without an
adequate amount of insulin, glucose in unable to get into the cells. It accumulates in the
blood, setting in motion a series of events which can ultimately prove fatal. When insulin
is deficient, the cells become starved for a source of energy. In response to this, the
body starts breaking down stores of fat and protein to use as alternative energy sources.
As a consequence, the cat eats more; thus, we have weight loss in a cat with a ravenous
appetite. The body tries to eliminate the excess glucose by eliminating it in the urine.
However, glucose (blood sugar) attracts water; thus, urine glucose takes with it large
quantities of the body's fluids, resulting in the production of a large amount of urine.
To avoid dehydration, the cat drinks more and more water.
Weight loss
Ravenous appetite
Increased water consumption
Increased urination
The diagnosis of diabetes mellitus is
based on three criteria: the four classical clinical signs, the presence of a persistently
high level of glucose in the blood stream, and the presence of glucose in the urine. The
normal level of glucose in the blood is 80-120 mg/dl (3.9-6.1 mmol/L). It may rise to
250-300 mg/dl 13.8-16.5 mmol/L) following a meal or when the cat is very excited. However,
diabetes is the only common disease that will cause the blood glucose level to rise above
400 mg/dl (22 mmol/L). Some diabetic cats will have a glucose level as high as 800 mg/dl
(44 mmol/L), although most will be in the range of 400-600 mg/dl (22-33 mmol/L). To keep
the body from losing its needed glucose, the kidneys do not allow glucose to be filtered
out of the blood stream until an excessive level is reached. This means that cats with a
normal blood glucose level will not have glucose in the urine. Diabetic cats, however,
have excessive amounts of glucose in the blood, so it will be present in the urine.
For the diabetic cat, one reality exists:
blood glucose cannot be normalized without treatment. Although the cat can go a day or so
without treatment and not get into a crisis, treatment should be looked upon as part of
the cat's daily routine. Treatment almost always requires some dietary changes. Whether an
individual cat will require oral therapy or insulin injections will vary.
There are two implications for the owner:
financial commitment and personal commitment. When your cat is well regulated, the
maintenance costs are minimal. The special diet, the oral medication, insulin, and
syringes are not expensive. However, the financial commitment is significant during the
initial regulation process and if complications arise.
Initially, your cat will be hospitalized
for a few days to deal with the immediate crisis and to begin the regulation process. The
"immediate crisis" is only great if your cat is so sick that it has quit eating
and drinking for several days. Cats in this state, called ketoacidosis, may require a week
or more of hospitalization with quite a bit of laboratory testing. Otherwise, the initial
hospitalization may be only for a day or two to get some testing done and to begin
treatment. At that point, your cat goes home for you to administer medication. At first,
return visits are required every 3-7 days to monitor progress. It may take a month or more
to achieve good regulation.
The financial commitment may again be
significant if complications arise. We will work with you to try and achieve consistent
regulation, but some cats are difficult to keep regulated. It is important that you pay
close attention to our instructions related to administration of medication, to diet, and
to home monitoring. Another complication that can arise is hypoglycemia or low blood
sugar; if severe, it may be fatal. This may occur due to inconsistencies in treatment or
because some cats can have a spontaneous remission of their disease. This will be
explained in subsequent paragraphs.
Your personal commitment to treating this
cat is very important in maintaining regulation and preventing crises. Most diabetic cats
require insulin injections twice daily, at about 12 hour intervals. They must be fed the
same food in the same amount on the same schedule every day. If you are out of town, your
cat must receive proper treatment while you are gone. These factors should be considered
carefully before deciding to treat a diabetic cat.
The best one word answer to that question
is consistency. Your cat needs consistent administration of medication, consistent
feeding, and a stable, stress-free lifestyle. To best achieve this, it is preferred that
your cat live indoors. Although that is not essential, indoor living removes many
uncontrollable variables that can disrupt regulation.
The first step in treatment is to alter
your cat's diet. Diets that are high in fiber are preferred because they are generally
lower in sugar and slower to be digested. This means that the cat does not have to process
a large amount of sugar at one time. The preferred diets are Prescription Diet Feline w/dJ
and CNM OMJ. If your cat is overweight, Prescription Diet Feline r/dJ is fed until the
proper weight is achieved, then your cat is switched to one of the others. Your cat's
feeding routine is also important. The average cat prefers to eat about 10-15 times per
day, one mouthful at a time. This means that food is left in the bowl at all times for
free choice feeding. However, this is not the best way to feed a diabetic cat. The
preferred way is to feed twice daily, just before each insulin injection. If your cat is
currently eating on a free choice basis, please try to make the change. However, if your
cat will not change or if you have several cats that eat in a free choice fashion, you may
find that this change is not practical. If a two-meals-per-day feeding routine will not
work for you, it is still very important that you find some way to accurately measure the
amount of food that is consumed. It is estimated that about 25% of diabetic cats have Type
II diabetes. This means that they can probably be treated with oral medication instead of
insulin injections. There is no reliable, practical test to know if your cat is one of
these. Therefore, your cat will be placed on an initial dose of glipizide or glyburide, an
oral hypoglycemic drug, for about 1 week. This is usually done at home if your cat is
eating well. Weekly blood glucose levels are checked until it is determined whether or not
response is occurring. If response occurs and blood sugar declines, this treatment is
continued until it is no longer effective. That may be for many years or for only a few
months, depending on the progression of destruction of the beta-cells in the pancreas.
The other form of treatment is
insulin injections. This approach is used for five classes of cats:
1. Cats that do not take tablets well.
2. Cats belonging to owners who cannot give tablets.
3. Cats that fail to respond to glipizide or glyburide.
4. Cats that have been ketoacidotic (because Type II
diabetics rarely become ketoacidotic).
5. Cats belonging to owners who find injections easier to
give than tablets.
Many people are initially fearful of
giving insulin injections. If this is your initial reaction, consider these points.
1. Insulin does not cause pain when it is injected.
2. The injections are made with very tiny needles that
your cat hardly feels.
3. The injections are given just under the skin in areas
in which it is almost impossible to cause damage to any vital organ. Please do not decide
whether to treat your cat with insulin until we have demonstrated the injection technique.
You will be pleasantly surprised at how easy it is.
About Insulin
Insulin comes in an airtight bottle that
is labeled with the insulin type and the concentration. Before using, mix the contents. It
says on the label to roll it gently, not shake it. The reason for this is to prevent foam
formation which will make accurate measuring difficult. The type of insulin used in cats
has a strong tendency to settle out of suspension. If it is not shaken properly, it will
not mix well, and dosing will not be accurate. Therefore, the trick is to shake it
vigorously enough to mix it without creating foam. Since bubbles can be removed (as
described later), it is more important to mix it well than to worry about foam formation.
Insulin is a hormone that will lose its effectiveness if exposed to direct sunlight or
high temperatures. It should be kept in the refrigerator, but it should not be frozen. It
is not ruined if left out of the refrigerator for a day or two, although this is not
advisable. Insulin is safe as long as it is used as directed, but it should be kept out of
reach of children.
Drawing up the Insulin: Have the syringe
and needle, insulin bottle, and cat ready. Then, follow these steps:
1. Remove the guard from the needle, and draw back the
plunger to the appropriate dose level.
2. Carefully insert the needle into the insulin bottle.
3. Inject air into the bottle; this prevents a vacuum
from forming within the bottle.
4. Withdraw the correct amount of insulin into the
syringe.
Before injecting your cat with the
insulin, check that there are no air bubbles in the syringe. If you get an air bubble,
draw twice as much insulin into the syringe as you need. Then withdraw the needle from the
insulin bottle and tap the barrel of the syringe with your finger to make the air bubble
rise to the nozzle of the syringe. Gently and slowly expel the air bubble by moving the
plunger upward. When this has been done, check that you have the correct amount of insulin
in the syringe. The correct dose of insulin can be assured if you measure from the needle
end, or "0" on the syringe barrel, to the end of the plunger nearest the needle.
Injecting the Insulin: The steps to follow
for injecting insulin are:
1. Hold the syringe in your right hand (switch hands if
you are left-handed).
2. Have someone hold your cat while you pick up a fold of
skin from somewhere along your cat's back with your free hand (pick up a different spot
each day).
3. Quickly push the very sharp, very thin needle through
your cat's skin. This should be easy and painless. However, take care to push the needle
through only one layer of skin and not into your finger or through two layers of skin. The
latter will result in injecting the insulin onto your cat's haircoat or onto the floor.
4. To inject the insulin, place your thumb on the plunger
and push it all the way into the syringe barrel.
5. Withdraw the needle from your cat's skin. Immediately
place the needle guard over the needle and discard the needle and syringe.
6. Stroke your cat to reward it for sitting quietly.
7. Be aware that some communities have strict rules about
disposal of medical waste material so don't throw the needle/syringe into the trash until
you know if this is permissible. If it is not, we can dispose of them for you.
There are four reasons NOT to swab
the skin with alcohol to "sterilize" it.
1.Due to the nature of the thick hair coat and the type
of bacteria that live near the skin of cats, brief swabbing with alcohol or any other
antiseptic is not effective.
2.Because a small amount of alcohol can be carried
through the skin by the needle, it may actually carry bacteria with it into the skin.
3.The sting caused by the alcohol can make your cat
dislike the injections.
4.If you have accidentally injected the insulin on the
surface of the skin, you will not know it. If you do not use alcohol and the skin or hair
is wet following an injection, the injection was not done properly.
Although the above procedures may at first
seem complicated and somewhat overwhelming, they will very quickly become second nature.
Your cat will soon learn that once or twice each day it has to sit still for a few
minutes. In most cases, a reward of stroking results in a fully cooperative cat that
eventually may not even need to be held.
It is necessary that your cat's progress
be checked on a regular basis. Monitoring is a joint project on which owners and
veterinarians must work together.
Home Monitoring
Your part consists of two forms of
monitoring. First, you need to be constantly aware of your cat's appetite, weight, water
consumption, and urine output. You should be feeding a constant amount of food each day
which will allow you to be aware of days that your cat does not eat all of it or is
unusually hungry after the feeding. You should weigh your cat at least once monthly. It is
best to use the same scales each time. A baby scale works well for this.
You should develop a way to measure water
consumption. The average 10 pound (4.5 kg) cat should drink no more than 7 1/2 oz. (225
ml) of water per 24 hours. Since this is highly variable from one cat to another, keeping
a record of your cat's water consumption for a few weeks will allow you to establish what
is normal for your cat. Another way to measure water consumption is based on the number of
times it drinks each day. When properly regulated, it should drink no more than four times
per day. If this is exceeded, you should take steps to make an actual measurement.
Urine output can be measured by
determining the amount of litter that is scooped out of the litter box. This is a little
less accurate if you have more than one cat that uses the litter box, but it can still be
meaningful. The best way to measure litter is to use a clumping litter and scoop it into a
sealable container. After a few weeks you will be able to know the normal rate at which
the jar fills. Too rapid filling will indicate that your cat's urine production has
increased.
Any significant change in your cat's food
intake, weight, water intake, or urine output is an indicator that the diabetes is not
well controlled. We should see the cat at that time for blood testing.
The second method of home monitoring is to
determine the presence of glucose in the urine. If your cat is properly regulated, there
should be no glucose present in the urine. You may purchase urine glucose test strips in
any pharmacy. They are designed for use in humans with diabetes, but they will also work
in the cat. The use of special non-absorbing kitty litter permits you to dip the test
strip into urine in the litter box. Aquarium gravel, Styrofoam packing
"peanuts," and commercial non-absorbing litter can be used. Since these are not
ideal litter materials, they are best used on a periodic basis.
Another method is as follows:
1. Put about 1 tablespoon of wet litter in a small cup.
(A clay type litter is required; clumping litter will not work.)
2. Add about 1 tablespoon of tap water to the litter and
stir.
3. Dip a urine glucose test strip into the liquid and
read it according to the directions on the bottle.
4. The results will be about half of the actual urine
glucose amount because of the dilution of the added water.
If glucose is detected by either method,
the test should be repeated the next two days. If it is present each time, we should see
your cat for a blood test.
Monitoring of Blood Glucose
Determining the level of glucose in the
blood is the most accurate means of monitoring. This should be done about every 3-4 months
if your cat seems to be well regulated. It should also be done at any time the clinical
signs of diabetes are present or if glucose is detected in the urine for two consecutive
days.
Timing is important when the blood glucose
is determined. Since eating will elevate the blood sugar for several hours, it is best to
test the blood at least 6 hours after eating. When testing the blood we want to know the
highest and lowest glucose readings for the day. The highest reading should occur just
before an injection of insulin is given. The lowest should occur at the time of peak
insulin effect. This is usually 5-8 hours after an insulin injection, but it should have
been determined during the initial regulation process. Therefore, the proper procedure is
as follows:
1. Feed your cat its normal morning meal then bring it to
hospital immediately. If you cannot get it to the hospital within 30 minutes, do not feed
it. In that situation, bring its food with you.
2. Bring your cat to the hospital early in the morning
without giving it insulin.
3. A blood sample will be taken immediately, then we will
give insulin and feed your cat if it did not eat at home.
4. A second blood sample will be taken at the time of
peak insulin effect.
If your cat gets excited or very nervous
when riding in the car or being in the hospital, the glucose readings will be falsely
elevated. If this occurs, it is best to admit your cat to the hospital the morning (or
afternoon) before testing so it can settle down for testing the next day. Otherwise, the
tests give us limited information.
Hypoglycemia means low blood sugar. If it
is below 40 mg/dl (2.2 mmol/L), it can be life-threatening. Hypoglycemia occurs under
three conditions:
1) If the insulin dose is too high. Although most
cats will require the same dose of insulin for long periods of time, it is possible for
the cat's insulin requirements to change. However, the most common causes for change are a
reduction in food intake and an increase in exercise or activity. The reason for feeding
before the insulin injection is so you can know when the appetite changes. If your cat
does not eat, skip that dose of insulin. If only half of the food is eaten just give a
half dose of insulin. Always remember that it is better for the blood sugar to be too
high than too low.
2) If too much insulin is given. This can occur
because the insulin was not properly measured in the syringe or because two doses were
given. You may forget that you gave it and repeat it, or two people in the family may each
give a dose. A chart to record insulin administration will help to prevent the cat being
treated twice.
3) If your cat has a spontaneous remission of the
diabetes. This is a poorly understood phenomenon, but it definitely occurs in many
cats. They can be diabetic and on treatment for many months, then suddenly no longer be
diabetic. Since this is not predictable and happens quite suddenly, a hypoglycemic crisis
("insulin shock") is usually the first indication.
The most likely time that a cat will
become hypoglycemic is the time of peak insulin effect (5-8 hours after an insulin
injection). When the blood glucose is only mildly low, the cat will be very tired and
unresponsive. You may call it and get no response. Within a few hours, the blood glucose
will rise, and your cat will return to normal. Since many cats sleep a lot during the day,
this important sign is easily missed. Watch for it; it is the first sign of impending
problems. If you see it, please bring in your cat for blood testing.
If your cat is slow to recover from this
period of lethargy, you should give it corn syrup (1 tablespoon by mouth) or feed one
packet of a semi-moist cat food. If there is no response in 15 minutes, repeat the corn
syrup or the semi-moist food. If there is still no response, contact us immediately for
further instructions. (Note: Diabetic cats should not be fed semi-moist foods except
for this situation.)
If severe hypoglycemia occurs, a cat will
have seizures or lose consciousness. This is an emergency that can only be reversed with
intravenous administration of glucose. If it occurs during office hours, come in
immediately. If it occurs at night or on the weekend, call our emergency phone number for
instructions.
This is a poorly understood phenomenon
that only happens in a few cats. Unfortunately, it can happen rather suddenly so a
hypoglycemic crisis may be created when the normal amount of insulin is given. When it
occurs, the cat may be normal for a few weeks or for many months. However, diabetes will
almost always return. Therefore, you should watch for the typical signs of diabetes then
contact us for insulin instructions.
1. Read and reread this material so that you understand
the specifics of proper regulation and how to recognize and treat hypoglycemia.
2. Get the supplies for treatment. Your prescription will
specify the type of insulin and syringes. If you will be using urine glucose tests strips,
they should be purchased at a pharmacy
3. Give the first injection of insulin of _____units at
about _________ AM/PM.
4. Return for a glucose curve, no later than 8:00 a.m.,
on ____________. Feed your cat that morning and immediately bring it to the hospital. Do
not give insulin, but bring it with you. (If it will take more than 30 minutes to drive to
the hospital, call for instructions on feeding.)
5. Following regulation in the hospital, measure the
urine glucose 2 consecutive days, then twice weekly for the next 2 weeks. If glucose is
not detected, measure the glucose 2 consecutive days every other week.
6. If you are unable to test the urine for glucose,
return to our hospital in 2-4 days for a blood glucose test. This should be done about 5-8
hours after an injection of insulin. If two injections are given each day, be sure the
test is done before the evening injection.
7. Return to our hospital for a blood
glucose test in 1 month. This should be done about 5-8 hours after an injection of
insulin. If two injections are given each day, be sure the test is done before the
evening injection.