What is diabetes mellitus?
There are two forms of diabetes in dogs: diabetes insipidus (drinking diabetes)
and diabetes mellitus (sugar diabetes) Diabetes insipidus is a very rare disorder
that results in failure to regulate body water content. Your dog has the more
common type of diabetes: diabetes mellitus. This is a fairly common disorder
and is most often seen in dogs 5 years of age or older. There is a congenital
form that occurs in puppies, but this is not common. Diabetes mellitus is a
disease of the pancreas. This 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. Simply put, diabetes mellitus
a failure of the pancreas to regulate blood sugar.
Some people with diabetes have to have daily injections of insulin and others
take oral medication. Is this true for dogs?
In humans, 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 of the pancreas. This is the only
type of diabetes known in dogs. As the name implies, dogs with this type of
diabetes require insulin injections to stabilise 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
and there is a delayed response in secreting it. People with this form may be
treated with an oral drug that stimulates the remaining functional cells to
produce or release insulin in an adequate amount to normalise blood sugar. Because
Type II diabetes does not occur in dogs, oral medications are not appropriate
for treating diabetic dogs.
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 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 dog eats more; thus,
we have weight loss in a dog with a ravenous appetite. The body tries to eliminate
the excess glucose by excreting it in the urine. However, the excess 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 dog drinks more and more water. Thus, we have the four classical signs of
CLASSICAL SIGNS OF DIABETES MELLITUS 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 blood glucose and
the presence of glucose in the urine.
The normal level of glucose in the blood is 80-120 mg/dl (4.4-6.6 mmol/l).
It may rise to 250-300 mg/dl (13.8-16.7 mmol/l) following a meal. 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 dogs 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
To prevent glucose loss from the body the kidneys only allow it to be filtered
out of the blood stream when very high levels of glucose are circulating in
the blood. This means that dogs with a normal blood glucose level will not have
glucose in the urine. Diabetic dogs, however, have excessive amounts of glucose
in the blood, so it will be present in the urine.
What are the implications for me and my dog?
For the diabetic dog, one reality exists: blood glucose cannot be normalised
without treatment. Although the dog can go a day or so without treatment and
not get into a crisis, treatment should be looked upon as part of the dog's
daily routine. Treatment almost always requires some dietary changes and administration
For the owner, there are two implications: financial commitment and personal
When your dog is well regulated, the maintenance costs are minimal. The special
diet, insulin, and syringes are not very expensive. However, the financial commitment
is significant during the initial regulation process and if complications arise.
Initially, your dog may be hospitalised for a few days to deal with the immediate
crisis and to begin the regulation process. The "immediate crisis" is only great
if the dog is so sick that it has stopped eating and drinking for several days.
Dogs in this state, called ketoacidosis, may require a week or more of hospitalisation
with a number of laboratory tests. Otherwise, the initial hospitalisation may
be only for a day or two in order to start stabilisation. At that point, your
dog goes home for you to administer medication. At first, return visits are
required frequently to monitor progress. It may take a month or more to achieve
The financial commitment may again be significant if complications arise.
Another complication that can arise is hypoglycemia, or low blood sugar. If
severe, this can be fatal. This may occur due to inconsistencies in treatment.
This will be explained in subsequent paragraphs.
Your personal commitment to treating your dog is very important in maintaining
regulation and preventing crises. Most diabetic dogs require insulin injections
once or even twice daily. They must be fed the same food in the same amount
on the same schedule every day. If you are out of town, your dog must receive
proper treatment while you are gone. These factors should be considered carefully
before deciding to commence treatment.
What is involved in treatment?
Consistency is vital to proper management of the diabetic dog. Your dog needs
consistent administration of medication, consistent feeding, and a stable, stress-free
lifestyle. To best achieve this, it is preferred that your dog 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 dog's diet. Diets that are high
in fibre are preferred because they are generally lower in sugar and slower
to be digested. This means that the dog does not have to process a large amount
of sugar at one time. The preferred diets are on prescription but will be supplied
by your veterinary surgeon. If your dog is overweight, a special weight reducing
diet may be first prescribed and then once the proper weight is achieved, another
diet will be introduced.
Your dog's feeding routine is also important. The best way to feed a diabetic
dog is to feed twice daily. If a small meal is given at the time of the insulin
injection the chances are that the patient won't even notice it. If your dog
is currently eating on a free choice basis, please try to make the change. However,
if your dog will not change or if you have several dogs 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.
The foundation for regulating blood glucose is the administration of insulin
by injection. Many people are initially afraid 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 dog hardly feels.
The injected volumes are minute.
3. The injections are given just under the skin in areas in which it is almost
impossible to cause damage to any vital organ.
The injection technique is as follows:
About Insulin. Insulin comes in an airtight bottle that is labelled
with the insulin type and the concentration. Shake the bottle to mix the contents.
Some of the types of insulin used in dogs have 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 the reach of children.
Drawing up the Insulin. Have the syringe and needle, insulin bottle,
and dog ready and:-
1. Remove the guard from the needle, and draw back the plunger to the appropriate
2. Carefully insert the needle into the insulin bottle.
3. Inject air into the bottle; this prevents a vacuum from forming within
4. Withdraw the correct amount of insulin into the syringe.
Before injecting your dog 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
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
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. Pick up a fold of skin from somewhere along your dog's back with your
free hand (pick up a different spot each day).
3. Quickly push the very sharp, very thin needle through your dog'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 dog's haricoat 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 dog's skin. Immediately place the needle
guard over the needle and discard the needle and syringe.
6. Stroke your dog 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 rubbish until you
know if this is permissible.
It is neither necessary nor desirable to swab the skin with alcohol to "sterilise"
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 dogs, brief swabbing with alcohol or any other antiseptic
is not very 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 dog 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.
However it is useful to use a spirit swab to sterilise the insulin vial before
you withdraw the dose of insulin. Similarly the needle can be wiped with the
swab if you are using the syringe and needle more than once. This is cost effective
but is strictly not to be recommended.
Although the above procedures may at first seem complicated and somewhat overwhelming,
they will very quickly become second nature. Your dog 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 dog that eventually may not even
need to be held.
Is continual or periodic monitoring needed?
It is necessary that your dog's progress be checked on a regular basis. Monitoring
is a joint project on which owners and veterinary surgeon must work together.
Your part consists of two forms of monitoring. First, you need to be constantly
aware of your dog'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 dog does not eat all of it or is unusually hungry
after the feeding. You should weigh your dog at least once monthly. It is best
to use the same scales each time.
You should develop a way to measure water consumption. The average dog should
drink no more than approximately 250 ml. (7 1/2 oz) of water per 5 kg (10 pounds)of
body weight per 24 hours. Since this is highly variable from one dog to another,
keeping a record of your dog's water consumption for a few weeks will allow
you to establish what is normal for your dog. 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 six times per day. If this is exceeded, you should
take steps to make an actual measurement.
Any significant change in your dog's food intake, weight, water intake, or
urine output is an indicator that the diabetes is not well controlled. Your
veterinarian should see your dog at that time for blood testing.
The second method of home monitoring is to determine the presence of glucose
in the urine. If your dog is properly regulated, there should be no glucose
or only a minimal amount present in the urine.
There are several ways to detect glucose in urine. You may purchase urine
glucose test strips in any chemist or your veterinarian will supply them. They
are designed for use in humans with diabetes, but they will also work in the
dog. A fresh urine sample should be collected and tested with the test strip.
If glucose is detected, the test should be repeated the next two days. If it
is present each time, your veterinarian should see your dog for a blood test.
You should keep a small container to catch urine as the dog voids.Your veterinarian
can supply these. A large amount of urine is not needed to test for urine glucose;
it is not necessary to catch the entire amount of urine. Because the female
dog usually squats to urinate, a shallow pan or dish may be placed under the
hindquarters when she begins to urinate. For male dogs, urine can be collected
as soon as the dog lifts the leg to void. Male dogs often urinate small amounts
in several different places and most often urinate on vertical objects, such
as bushes and trees.
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 dog seems to
be well regulated. It should also be done at any time the clinical signs of
diabetes are present or if appreciable amounts of glucose are detected in the
urine for several 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 your veterinarian will 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 dog its normal morning meal then bring it to the surgery immediately.
If you cannot get it there within 30 minutes, do not feed it. In that situation,
bring it's food with you.
2. Bring your dog to the surgery early in the morning without giving it insulin.
3. A blood sample will be taken immediately, then your veterinarian will
give insulin and feed your dog if it did not eat at home.
4. A second blood sample will be taken at the time of peak insulin effect.
If your dog gets excited or very nervous when riding in the car or being in
the hospital, the glucose readings may be falsely elevated. If this occurs,
it is best to admit your dog to the surgery in the morning (or afternoon) before
testing so it can settle down for testing the next day. In this way the tests
are likely to be more accurate.
Does hypoglycaemia (low blood sugar) occur in dogs?
Hypoglycaemia means low blood sugar. If it is below 40 mg/dl (2.2 mmol/l),
it can be life-threatening. Hypoglycaemia occurs under two conditions:
1. If the insulin dose is too high. Although most dogs will require the same
dose of insulin for long periods of time, it is possible for the dog'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 dog 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 dog
being treated twice.
The most likely time that a dog will become hypoglycaemic is the time of peak
insulin effect (5-8 hours after an insulin injection). When the blood glucose
is only mildly low, the dog 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 dog will return to normal. Since many dogs sleep a lot during the day,
this important sign is easily missed. Watch for it; it is the first sign of
If your dog is slow to recover from this period of lethargy, you can try feeding
sugar or glucose. A teaspoonful of sugar in a little water, poured into the
dog, should bring about an improvement. If not repeat it after 15 minutes.
If there is still no response, contact your veterinarian immediately for further
If severe hypoglycaemia occurs, a dog will have seizures or lose consciousness.
This can only be reversed with intravenous administration of glucose. Please
telephone your veterinarian immediately, be it day or night. THIS IS AN EMERGENCY.
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