Diabetes Mellitus
D i a b e te s M e l l i t u s
What is Diabetes Mellitus
Before we explain what is going wrong inside a diabetic patient lets first give a little lesson on
how a body’s normal metabolism works. The cells in our bodies need sugar known as glucose
in order to work properly. The cells of the body need the hormone known as insulin to make
glucose usable. Insulin is produced by the pancreas and is the key to unlocking the door that
separates our cells from the sugars in our bloodstream.
In a diabetic the pancreas is no longer producing enough insulin. Without the insulin the cells
of the body can no longer detect or use the sugar in the bloodstream. These cells begin starve
and put out a call to the body that starvation is occurring. The body then begins to try to eat
more in order to fuel the cells but without insulin the cells still cannot detect sugar in the
blood stream. At this point the body begins to break down its own starches, proteins, and fats
in order to fuel the cells. By this time there is an overabundance of unused glucose in the
bloodstream. There gets to be such a high amount of glucose that the kidneys cannot filter it
all out. Glucose begins to spill over into the urine. As glucose spills into the urine it draws a
large amount of fluid with it. This leads to the increased urination and increased thirst that
often accompanies diabetes.
Main Symptoms of Diabetes are:
Dramatically Increased Appetite
Increased Thirst
Increased Urination
Weight Loss
Muscle Weakness and Abnormal Gait in Cats
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Diabetes Mellitus
Diabetes Mellitus
Diagnosis
Diagnosis usually begins with a urinalysis to look for the presents of sugar in the urine. When
sugar is present in the urine a blood sample is then taken to evaluate the amount of sugar in
the bloodstream, as well as the health of the other organs of the body. With the combination
of sugar in the urine and a high glucose level the diagnosis of diabetes is reached.
Treatment
The foundation of diabetes treatment and regulation is insulin injections. Most dogs require
subcutaneous injections (under the skin) every 12 hours. Most patients are currently using human
insulin called Vetsulin. This insulin is purchased at a veterinary clinic and must be kept refrigerated.
Special diets are sometimes added to aid in regulation of diabetes. These foods help to stimulate the
pancreas to produce as much insulin as it can as well as slowly releasing sugar into the blood stream.
For diabetic cats a food that is low in carbohydrates and high in protein is recommended while dogs
usually need a food higher in fiber.
Once insulin has been started the next step is finding the proper dose to get the patient’s blood sugar
regulated. This can be the most frustrating part for owners because it requires many all day trips to
the veterinarian for a glucose curve. A glucose curve is a series of tests that allows your veterinarian to
map out how long the insulin lasts in the body as well as how effectively it is lowering the blood sugar.
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Diabetes Mellitus
Diabetes Mellitus
Giving Insulin
First, feed your pet. A pet that has not eaten a normal meal but receives insulin may drop his or her
blood sugar to a dangerous low level. If your pet is not eating, this could indicate a need for a
checkup with your veterinarian. After the pet has eaten, you are ready to give the injection.
Before drawing up the insulin in a syringe, roll the bottle back and forth in your palms so that the
white material in the bottom is mixed in to the rest of the solution. Do not shake the bottle as the
insulin molecule can be damaged.
When drawing up the insulin, always hold the bottle vertically to avoid unnecessary bubbles in the
syringe. Since insulin is being given under the skin, the presence of bubbles is not an enormous
problem (as it would be with an intravenous injection) but we still want to minimize the presence of
bubbles. If you get bubbles in the syringe, flick the syringe with your fingers until the bubble rises to
the top and then simply push the air out of the syringe with the plunger.
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Diabetes Mellitus
Diabetes Mellitus
After you have the insulin dose ready in the syringe it is time to get your dog. Be sure you can trust
your dog to hold reasonably still for the shot. Most dogs do not require a second person to hold them
still but some dogs are very rambunctious and a helper is necessary. If you have such a pet but no
helper, consider tying your dog’s leash short around a piece of furniture. (Use a slip knot in case of
choking emergency.) Some dogs are very uncooperative and require a muzzle.
Lift up a fold of skin ideally along the side of the body. This will create a small space for the needle.
Insert the needle into this space and inject the insulin. Withdraw the syringe and needle when you are
finished.
Complications of Diabetes Mellitus
Diabetic Cataracts
The lens of the eye is round, hard, and normally as clear as glass. Looking at the lens it is hard to believe it is a
piece of living tissue. The lens is suspended by fibers which can adjust its position so that one can focus. The
lens is encased in a capsule and depends on the fluids of the eye for nutrients. The lens does not receive a
direct blood supply. Normally, the lens absorbs glucose from the eye fluids, using most of this for its own
energy needs. Some of the excess is converted to another sugar called “sorbitol.” When there is excess sugar
in the eye fluids, there is excess sorbitol produced. Sorbitol pulls water into the lens which in turn disrupts
lens clarity and causes the cataract. Fructose is also produced from the excess glucose and also contributes to
this water imbibition. The presence of cataracts does not necessarily imply poor diabetic control. Even well
controlled dogs still can get cataracts. Generally the cataract has matured and the dog is blind in a matter of
weeks.
If your dog develops blindness due to cataracts there are two options. The first option is to do nothing, dog’s
often do very well adjusting to blindness as long as their environment remains the same. Dogs do not tend to
rely on their vision near as much as humans do. For more information on living with a blind dog the following
website may be helpful: www.blinddogs.com. The other option is surgical removal of the cataract by a
veterinary ophthalmologist. There are a couple of trusted ophthalmologists available for referrals. If you are
interested in pursuing removal please contact your veterinarian.
Ketoacidosis
Ketoacidosis is one of the most extreme complications of diabetes mellitus that can be experienced.
Unfortunately, most cases of ketoacidosis are in patients that were not previously known to be diabetic so the
owner (and pet) must deal with two serious diagnoses: one acutely life-threatening and expensive and the
other requiring on-going commitment and daily treatment.
Ketoacidosis represents an extreme metabolic derangement. Stress of some sort, usually some kind of
infection, inflammatory disease, or pancreatitis, creates a severe loss of glucose regulation. The cells are
starving for glucose and, even though there is plenty of glucose in the blood, without insulin this glucose
cannot enter the cells. In response to the starving body, all stored fuels are mobilized including fats. The
extreme fat burning situation leads to the production of ketone bodies. When ketone bodies are burned for
fuel, pH and electrolyte imbalances occur and the patient’s life is at risk. Shock and dehydration are only part
of this body-wide crisis. Nausea and appetite loss with marked listlessness is typically what the owner notices;
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Diabetes Mellitus
Diabetes Mellitus
prior signs of diabetes (excess thirst, appetite and weight loss) may have been ignored or unnoticed but at
this point the pet is clearly very ill. Blood glucoses are typically extremely high, and ketones can usually be
detected in the urine.
Insulin Shock
If your pet appears wobbly or drunken, his/her blood sugar level may have dropped too low. This occurs after
an insulin overdose. First try to get your pet to eat. If the pet will not eat, administer light Karo syrup, honey,
or even sugar-water at a dose of one tablespoon per 5 pounds. If no improvement occurs, immediately see
your veterinarian for emergency treatment. When your pet is more stable, a glucose curve will be needed to
determine why this happened and what a more appropriate insulin dose might be.
Urinary Tract Infections
Diabetics are particularly prone to urinary tract infections (UTIs) because hyperglycemia causes sugar to spill
into the urine, and that sugary urine, while still in the body, becomes friendly to bacterial cultures . Since
another symptom of hyperglycemia is excess urination, all the tissues of the urinary tract are being frequently
bathed with this sugary bacterial culture. The bacteria can migrate from the bladder to the kidneys causing
kidney infection if bladder infections are left untreated. The best prevention for this vicious circle is regulating
blood glucose as best you can and treating the UTI when it becomes apparent. This is usually done with
antibiotics.
Pancreatitis
Pancreatitis means the pancreas is inflamed. The inflammation can become severe, and the digestive enzymes
that are normally inactive can become active and the enzymes cause damage to the pancreas. This causes a
cycle of increasing inflammation. The pancreas has two separate functions: the endocrine function of blood
glucose regulation, and the exocrine function of digestion. When either of these functions are abnormal, it
may cause the other one to be disrupted. Diabetes can cause pancreatitis, and pancreatitis can cause
diabetes. When a diabetic animal has a bout of pancreatitis, any vomiting, lethargy, or necessary dietary
adjustments will likely require an adjustment to the insulin dose. Diabetic animals that have a bout of
pancreatitis may show some insulin resistance. This can become a complicated situation that requires extra
care and observation by both the vet and the owner.
Signs of acute pancreatitis
Lethargy or depression
Anorexia or inappetance
Vomiting (common in dogs, less common in cats)
Abdominal pain (dogs may show an unusual posture, cats tend to "hide" pain more)
Diarrhea (more common in dogs)
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Diabetes Mellitus
Dehydration
Jaundice (more common in dogs)
When do you need to return to your veterinarian?
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When your pet seems ill
If the pet is beginning to lose weight
When your pet’s appetite either dramatically increases or decreases
If your pet begins to drink and/or urinate excessively
If your pet becomes groggy or disoriented
Some pets are hard to regulate
Some pets seem to require re-regulation frequently. There may be an underlying reason to sort out. Here are
some possibilities should your pet seem to fit in this category:
Improper administration of insulin. If possible, have your doctor observe you giving the insulin to your pet.
Another possibility is that your insulin may be out of date.
Rapid insulin metabolism. Insulin wears off quickly in some animals. Your pet may require a different type of
insulin or even additional injections during the day.
Insulin overdose may actually lead to elevated glucose levels (and clinical signs of diabetes mellitus). In this
situation, too much insulin brings the blood glucose too low and other hormones respond to bring it back up
(and generally over-do it).
Steroid administration (such as prednisone, prednisolone etc.) will interfere with insulin.
Progesterone, a female hormone, also interferes with insulin. Unspayed female diabetics should be spayed
once they are sufficiently regulated
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