DIABETES MELLITUS IN CATS
Somewhere between 1 in 100 and 1 in 500 cats will develop diabetes during their lifetime. As pet obesity becomes more of a problem, these numbers are expected to increase.
What is diabetes
mellitus?
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. The more
common type of diabetes seen in cats is called diabetes mellitus.
This treatable disease is seen on a fairly regular basis, usually in cats 5 years
of age or older. The highest risk categories are older cats, obese cats, and male cats. Other contributing factors can include hyperthyroid disease (elevated thyroid function), chronic pancreatitis (long term inflammation of the pancreas), Cushing's Disease (also known as hyperadrenocorticism, or excessive production of cortisol by the adrenal glands), acromegaly (excessive growth hormone production by the pituitary gland), and the use of steroid medications. In some countries, the Birman breed appears to be at higher risk for diabetes, but this is not the case in the United States.
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 liver and stomach. It is shaped like an "L" and is made up of two
different groups of cells. One
type of cells produces the enzymes necessary for proper digestion. These enzymes help break down or "metabolize" fats, proteins and carbohydrates. The other group, called beta cells, produces
the hormone called insulin. Insulin is in charge of instructing the cells of the body to use the glucose that enters the blood stream after sugars are broken down.
Some people with
diabetes take insulin shots and others take oral medication. Is this true for cats?
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.
Why is insulin so
important?
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 and pass into 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 enter the cells. It builds up in the blood, setting in motion a series of
events, which can ultimately prove fatal.
When cells are not able to use the glucose in the blood because insulin is deficient, the cells become starved for
energy. Because cells need energy to function, and a cat's body needs functional cells to remain alive, the body
starts breaking down stores of fat and protein to use as alternative energy
sources.
Because the cat's cells are starving, the cat eats more, but because the diabetic cat can only get energy from stored fat and protein, and not the food that he is eating, he loses weight. Thus, we have weight loss in a cat with a ravenous appetite. The body tries to get rid of the excess
glucose by eliminating it in the urine.
However, along with the glucose, a large amount of body fluid is eliminated, too, because glucose (blood sugar) attracts water. This results in the
production of a large amount of urine.
To avoid dehydration, the cat becomes thirsty and drinks more and more water. Thus, we have the four classical signs of
diabetes:
- Weight loss
- Ravenous appetite
- Increased water consumption
- Increased urination
How is diabetes
mellitus diagnosed?
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.
What are the
implications for my cat and me?
For the diabetic cat, one reality exists: blood glucose
cannot be regulated normally without treatment.
Short term, the cat can compensate by digesting body stores of fat and protein, but over time, a condition called "ketoacidosis" can occur. This is due to the body's inability to handle excessive breakdown of fat and protein for energy - the waste products, called "ketones" build up in the blood and lower the blood pH, making it more acidic. Because the diabetic cat is already dehydrated, the situation becomes more severe. The signs of diabetic ketoacidosis (DKA) are:
- a ravenous cat that now has no appetite
- vomiting
- diarrhea
- lethargy
- weakness
- dehydration
- respiratory abnormalities
If a diabetic cat is having symptoms such as these, he should see a veterinarian immediately, as DKA can often require intensive care and IV fluid therapy.
Diabetic cats may develop unhealthy skin and flaky coat, liver disease, and
secondary bacterial infections. Because diabetics have very dilute and sugar-filled urine, they are at higher risk than the average cat for urinary tract infections. Untreated diabetics may become weak, developing a condition called "diabetic neuropathy". Cats with this disorder often walk with their hocks touching the ground and have trouble jumping.
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.
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 oral medication, insulin,
and syringes are not extremely expensive.
However, the financial commitment is significant during the initial regulation
process and if complications arise.
If applicable, 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. Ketoacidotic cats may require a week or more of hospitalization with quite a bit of
laboratory testing.
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 instructions related to administration of
medication, to diet, and to home monitoring.
Another complication that can arise is hypoglycemia or low blood sugar.
Severe hypoglycemia can be fatal. Hypoglycemia or low blood sugar is most commonly due to inconsistencies in treatment or because some cats can have a
spontaneous remission of their disease.
Your personal commitment to treating your 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.
What is involved in
treatment?
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 lives indoors.
Although that is not essential, indoor living removes many
uncontrollable variables that can disrupt regulation.
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| Drawing a dose of Lantus insulin from an insulin pen |
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.
Fortunately, there are more and more advanced feeding options available to help monitor your cat's food intake. Some new products on the market that may be helpful are the
MeowSpace Feeding and Litterbox Solution, or the soon-to-be-available
Sure Feed microchip or collar tag activated pet feeder. An exciting prospect that is on the horizon is the
Bistro Facial Recognition Smart Feeder. All these feeding options help multi-cat households control food access among their multiple cats to ensure that they have a better idea how well their diabetic is eating.
Since obesity is one of the predisposing factors for diabetes, making sure that your cat maintains a healthy, active lifestyle is important. Encouraging diabetic cats to eat a healthy, low carbohydrate, high protein diet, including 3-6oz canned food daily, may help encourage healthy weight loss.
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. 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.
** You
should replace your bottle of insulin every 6 months, regardless if the entire
content has been used. Studies have
found that insulin loses its effectiveness over a long period of time. **
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.
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| Various brands of U-100 insulin syringes |
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.
 |
| Proper subcutaneous injection techniques |
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/syringe into the sharp’s container. Stroke your cat to reward it for sitting
quietly.
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 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.
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.
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.
Is continual or
periodic monitoring needed?
Because a cat's need for insulin can change over time, and because some cats may experience "spontaneous remission", it is extremely important that your cat's progress be checked on a
regular basis. Monitoring is a joint
project on which owners and veterinarians must work together. Cats that have experienced a remission are at increased risk for becoming diabetic again, so monitoring in these cats is also important, despite the fact that they no longer require insulin therapy.
Home
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.
Keeping a daily diary, calendar or spreadsheet of your cat's weight, food intake, water intake, urine output and the timing of each insulin injection will help you feel comfortable and confident in your pet's progress, and will be very helpful for the veterinarian to assess at each checkup. 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
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.
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.
Does hypoglycemia
occur in cats?
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.
Tell me more about
spontaneous remission.
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.
Prognosis
Cats whose glucose levels are difficult to regulate or who require progressively large doses of insulin may require additional diagnostics to eliminate other concurrent or underlying diseases. Overall, cats with diabetes can be medically managed, and if they are stabilized, can live very happy and rewarding lives for years.
For after hours emergencies, please call the Oakland
Veterinary Emergency/Critical Care at 248-334-6877.
Additional resources:
AAFP Health Series: Diabetes
Caring For Your Diabetic Cat Video Series
International Cat Care Cat Health Series: Diabetes mellitus
Felinediabetes.com
My Cat Has Diabetes
Pet-Diabetes.com
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Diagnosis of the FLS is made from
blood tests for liver function and from a liver biopsy or aspirate. The latter involves inserting a very tiny
needle through the skin and into the liver, removing a small number of liver
cells, and examining those cells under the microscope. The FLS cat will have a large amount of fat
in and among the liver cells.
