Third Street
Veterinary Hospital, PC
McMinnville, Oregon 97128
Office phone: (503) 472-9418
Diabetes Mellitus
Treating a diabetic cat can be a challenge. Some cats just never seem to stay
regulated. However, there are several
important concepts that make this process much more likely to be successful.
1. Consistency:
Our goal is to find an appropriate dose of insulin that will last on a
long-term basis. In order to do that,
we must eliminate as many variables as possible. In other words, the more things that can stay the same from one
day to the next, the easier it is to keep a diabetic regulated. Our goal is to give the same dose of insulin
the same times each day, to feed the same food in the same quantities each day,
to keep the activity level the same each day, and to keep your cat's stress
level the same.
2. Tight control is not necessary in cats. Human diabetics must maintain blood glucose
values very close to normal at all times.
If they don't, they will develop some disastrous complications of
diabetes, such as loss of fingers, toes, feet, and hands, kidney failure, and
cataract formation. These complications
do not happen to diabetic cats. Therefore,
as stated above, it is better for the blood glucose to be too high than too
low.
3. Hyperglycemia (high blood glucose) is always
better than hypoglycemia (low blood glucose).
4. As the dose of insulin goes up, the blood
glucose goes down.
5. Food intake causes the blood glucose to
rise. Failure to eat allows the blood
glucose to fall below normal.
The latter three above principles are applied as
such: If you are not sure if you gave a
dose of insulin or if it was properly injected, do not give it again. If your cat does not eat, do not give
insulin. If you must miss a dose or two
of insulin (occasionally), do not be concerned. Your cat's blood glucose will get too high for a day or two, but
that will not cause great problems.
Understanding
Diabetes
There are two forms of diabetes in cats:
diabetes insipidus and diabetes mellitus.
Diabetes insipidus is a very rare disorder that results in failure to
regulate body water content. Your cat
has the more common type of diabetes, diabetes mellitus. This disease is seen on a fairly regular
basis, usually in cats 5 years of age or older. Simply put, diabetes mellitus is 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.
Types
of 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.
What
Insulin Does for the Body
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 is unable to get into the cells.
It accumulates in the blood, setting in motion a series of events that
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. Thus, we have the four
classical signs of diabetes:
CLASSICAL SIGNS OF DIABETES MELLITUS:
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. It may rise to 250-300
mg/dl 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. Some diabetic cats will have a glucose level
as high as 800 mg/dl, although most will be in the range of 400-600 mg/dl.
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.
The diagnosis of diabetes seems rather simple,
and in most cats it is. However, some
diabetic cats do not meet all the criteria.
For these, another test is performed called fructosamine. This test represents the average blood
glucose level for the past two weeks.
It minimizes the influence that stress and eating have on blood glucose
levels and can be very helpful in understanding difficult cases.
What
It Means for Your Cat to be Diabetic
For the diabetic cat, one reality exists. Blood glucose cannot be normalized without
treatment. Although the cat can go a
few days 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.
As for the owner, there are two implications:
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 can be
significant during the initial regulation process and if complications
arise.
In some cases, 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 5-7 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 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. Consistency is the key to prolonged
regulation. The more you keep the
medication, diet, and activity the same from one day to the next, the easier it
will be to keep your cat regulated.
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.
Treatment
As mentioned, the key to successful treatment 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 lives 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. If your cat is overweight, a reducing-type diet is fed until the proper
weight is achieved, then your cat is switched to a high fiber maintenance food.
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.
Fortunately, this is the best way to feed a diabetic cat. However, it is also desirable to monitor how
much food is eaten each day. We realize
that if you have more than one cat, this may be difficult, but please make an
effort, as this is part of the home monitoring that should occur.
The second step in treatment is to use a drug to
control (lower) control blood glucose levels.
The choices are to give insulin injections or to give an oral drug. Either is acceptable, and both have
advantages and disadvantages.
Insulin injections are usually the first choice
because this approach is to replace the hormone that is missing or made in
inadequate amounts. Although may people
are initially uncomfortable with the thought of giving injections, for most
cats, insulin injections are easier than giving tablets for reasons described
below.
This is generally our preferred way to treat
diabetic cats, especially if they are as follows:
1) Cats
that do not take tablets well.
2) Cats
belonging to owners who cannot give tablets.
3) Cats
that fail to respond to the oral drugs.
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. (Most cats are in this category. This is not because pills are hard to give
but because injections are very easy to give.)
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.
The second option for treatment is the use of a
tablet that lowers blood glucose. It is
estimated that as many as 25% of diabetic cats have Type II diabetes. This means that they may 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, we must place your
cat on an initial dose of glipizide or glyburide, the oral hypoglycemic drugs,
for about 1 week. This is usually done
at home if your cat is eating well.
Weekly blood glucose levels are checked for about one month 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.
One disadvantage to treating with tablets is
that some cats only have a temporary response.
The tablets function by stimulating the existing beta cells so they work
more efficiently. Many diabetic cats
have a gradual decline in the number of functioning beta cells as time
passes. This means that a time will
come with the tablets are no longer effective.
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. Some of the types of insulin used in cats settle
out of suspension in a few hours. 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 too much 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 as long as it is not
exposed to direct sunlight. However, we do not advise this. Insulin is safe as long as it is used as
directed, but it should be kept out of reach of children.
Several types of insulin are used in cats. Some are made for use in humans and obtained
from regular pharmacies. Protamine zinc
insulin (PZI) is made specifically for cats and obtained from
veterinarians. PZI has a concentration
of 40 units of active insulin crystals per milliliter of fluid. Thus it is called U40 insulin. Insulins made for humans have a
concentration of 100 units per milliliter and are called U100 insulins. This is important to know because there are
two types of insulin syringes, U40 syringes and U100 syringes. They are made to be used with their respective
types of insulin and must not be interchanged or improper dosing will occur.
Drawing
up 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,
verify 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
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 hair coat or onto the floor. The needle should be directed parallel to
the backbone or angled slightly downward.
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.
It is neither necessary nor desirable to swab
the skin with alcohol to "sterilize" it. There are four reasons:
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 does not
really kill all the bacteria.
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.
Monitoring
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 can be performed in one or both of two
ways. The first way is to monitor your cat for signs of diabetes. To do this, 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 twice
monthly. It is best to use the same
scales each time. A baby scale works
well for this. If you have several cats
that eat together and use the same litter box, monitoring weight is the best
because it is specific to this one cat.
If possible, 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.
There are several ways to detect glucose in
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
Hypoglycemia means low blood sugar. If it is below 40 mg/dl, 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
double 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 about 20% of diabetic 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.
Spontaneous
Remission
Spontaneous remission means that a diabetic cat
is no longer diabetic. This is a
phenomenon that happens in about 15-20% of diabetic cats. Unfortunately, it can happen rather suddenly
so a hypoglycemic crisis may be created because the owner does not realize
remission has occurred and continues to give the normal amount of insulin
.
For a few days after remission occurs, the cat
is able to make emergency amounts of glucose as the blood glucose level falls
to dangerously low levels. It does so
by converting glycogen, a product stored in the liver, to glucose and releasing
it into the blood stream. However, at
some point in time the glycogen stores are depleted and it can no longer
respond; a hypoglycemic crisis then occurs.
When it occurs, the cat may be normal for a few
weeks or for many months. However,
diabetes will almost always return because these cats have limited ability to
make insulin. Therefore, you should
watch for the typical signs of diabetes then contact us for insulin
instructions.
SUMMARY OF INSTRUCTIONS FOR CATS RECEIVING INSULIN
INJECTIONS
1) Read
and reread this material so that you understand the specifics of proper
regulation and how to recognize and treat hypoglycemia.
2) Give
the first injection of insulin of _____units at about _________ AM/PM.
3)
Return for a glucose curve at about the same time as you normally give
insulin in 5-7 days. Allow your cat to
eat through the night or feed it 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.)
4) Feed
your cat one of the foods mentioned above.
SUMMARY OF INSTRUCTIONS FOR CATS RECEIVING GLIPIZIDE OR
GLYBURIDE TABLETS
1) Have the prescription filled at any pharmacy.
2) Read and reread this material so that you
understand the specifics of proper regulation and how to recognize and treat
hypoglycemia. If hypoglycemia occurs,
discontinue glipizide or glyburide until consulting us.
3) Give _____ tablet (_____ mg) twice daily
(about every 12 hours) for 1 week.
Return for a blood test about 6-8 hours following tablet administration.
4) Feed your cat one of the foods mentioned
above.