HERE ARE THE TAKE-HOMES
FOR PET DIABETES

• DIABETES MELLITUS IS CAUSED BY A DEFICIENCY OF INSULIN. YOU ARE
  PROBABLY GOING TO HAVE TO GIVE INJECTIONS OF INSULIN AS A REPLACEMENT.
  (DON'T WORRY. IT'S EASIER THAN YOU THINK).
  
  
• The main symptoms of diabetes mellitus are excessive urination, excessive thirst,
  excessive appetite, and weight loss. Treatment should control these symptoms.
  
  
• Watching for these symptoms is the best way to know how your pet is doing.
  
  
• THE STARTING INSULIN DOSE IS GOING TO BE BASED ON AVERAGES
  AND WILL BE TWEAKED BASED ON TRIAL AND ERROR DEPENDING
  ON BOTH TEST RESULTS AND CONTROL OF THE SYMPTOMS.
  
  
• YOU CAN SAVE A LOT OF MONEY IF YOU GET YOUR OWN GLUCOSE METER
  AND LEARN TO DO BLOOD SAMPLING AT HOME (IT'S EASIER THAN YOU THINK).
  
  
• USING TOO LITTLE INSULIN IS A PROBLEM IN THE LONG TERM
  BUT TOO MUCH INSULIN IS POTENTIALLY AN EMERGENCY IN THE SHORT TERM.
  BE SURE YOU KNOW HOW TO RECOGNIZE HYPOGLYCEMIA AND WHAT TO DO ABOUT IT.
  
  

WHAT IS DIABETES MELLITUS?

In order to understand the problems involved in diabetes mellitus it is necessary to understand something of the normal body's sugar metabolism.

The cells of the body require fuel in the form of fat or sugar to conduct their daily activities. Some tissues can use either sugar or fat depending on circumstances and some tissues (such as the brain and nervous system) depend almost exclusively on sugar as fuel. Diabetes mellitus mostly involves the metabolism of sugar (in particular, a sugar known as glucose) so we will focus on the sugar part of the situation. Glucose comes from the diet in the form of starches and sugars that we eat.

Tissues cannot absorb glucose unless a hormone known as insulin is present. This special hormone, insulin, is produced by the pancreas as part of the body's natural blood sugar regulation. Insulin can be considered to be a key that unlocks the door allowing sugar in the bloodstream to enter the cells of the body. Once inside the tissues, glucose can be burned for fuel or stored but without insulin, the sugar stays in the bloodstream and cannot be used by the body.

The pancreas is nestled along the stomach and small
intestine.  It secretes digestive enzymes into the
small intestine but it also secretes hormones into
the bloodstream to regulate blood sugar.
(original graphic by marvistavet.com)

Imagine you're in your home on lock-down and you need food.
You call a delivery service, they bring food,
you open your door and get your food.
You can eat the food right away or store it for later.
The system works.

Now imagine you can't open your door and are sealed in.
There is no way to access the food on your doorstep.
Inside with no way to get to the food, you begin to starve
and consume everything possible inside.
Outside food accumulates to a point it must be dumped.
In this analogy, insulin would be the key
that allows your door to unlock.

IN THE DIABETIC ANIMAL THERE ISN'T ENOUGH INSULIN

In fact, there may be no insulin at all. Remember that insulin was the key to unlock the cell so that glucose could be brought inside. With no insulin, glucose cannot get in. Not only is glucose not being taken in and stored, but it is left floating around in the bloodstream in extremely high amounts. The body's tissues are starving and the bloodstream has plenty of glucose to feed them but without insulin, the glucose is unavailable.

SO WHAT SYMPTOMS RESULT FROM THIS?

Because there is no way to remove the glucose from the bloodstream, blood sugar levels are astronomically high. Normally, the kidney is able to conserve the bloodstream's glucose but its mechanisms are overwhelmed and glucose spills into the urine in high amounts. If we continue our food delivery analogy, all the undeliverable food must be dumped. In the body, glucose dumping happens in the kidney with extra glucose dumping in the urine. This process involves the use of a lot of water with the ultimate result being a lot of urine being produced to process all that glucose to dump. This translates into Excessive Thirst and Excessive Urination.

The tissues of the body are unable to access any of the glucose they need for fuel and are basically starving. Fat is mobilized and muscle is broken down to help feed the tissues but it does not do much good without insulin to bring fuel inside the cells. The patient shows Excessive Appetite because his/her body is in a state of starvation. Because the body is rapidly breaking itself down, Weight Loss is also a classic sign.

All the sugar in the urine presents a desirable growth medium for bacteria and Urinary Tract Infection is a common finding in diabetes mellitus.

In diabetic dogs (but not cats), a special type of cataract rapidly develops in the eye when glucose enter the lens of the eye in high amounts. Glucose normally feeds the lens of the eye but the amounts of glucose coming into the lens in the diabetic state are much higher. Excess glucose is converted to another sugar called sorbitol, which in turn attracts water. The excess water disrupts the clarity of the lens creating a diabetic cataract which leads to blindness in almost all diabetic dogs.

The main symptoms of Diabetes Mellitus are:

Excessive Thirst
Excessive Urination
Excessive Appetite
Weight Loss

(original graphic by marvistavet.com)

(original graphic by marvistavet.com)

First, an insulin type and dose will need to be selected. There are several types of insulins to select from and it is not possible to know exactly how much insulin your individual pet will require; trial and error is needed. Your veterinarian will make a guess based on what works for other cats and dogs and what has been reported in the literature. Most pets require injections twice a day, approximately 12 hours apart, in conjunction with a meal. Because overdose of insulin is potentially an emergency, it may be prudent to start with once a day insulin, just in case. If you like, discuss the pros and cons of each approach with your veterinarian.

Insulin has traditionally been given by syringe in a shot but insulin pens are proving more and more popular. The syringe method involves buying a box of syringes and a bottle of insulin, drawing up a measured amount of insulin and giving a shot. The pen involves applying a needle tip to the "pen," dialing a dose on the "pen," sticking the tip into the pet's skin and pressing a button on the "pen." Most people feel the pen method is much easier to perform but it may be difficult to find needle tips that are long enough for pet use as pet skin is much thicker than human skin. In some situations, the pen is used as a dispenser for the syringe as the pen cartridges may be more cost effective than bottles of insulin. Without video or first hand experience with insulin pens or syringes, it may be hard to visualize the difference. See our section on insulin administration for dogs or insulin administration for cats for details. Not all pet insulins are available in a pen format. Your veterinarian will instruct you regarding option.

Insulin and syringe
(Photocredit: Public Domain Image via Wikimedia Commons)

(original graphic by marvistavet.com)

(original graphic by marvistavet.com)

CONTINUOUS MONITORING

Continuous monitors have changed the way diabetic pets are monitored. A sensor with a tiny needle is implanted on the pet and paired wirelessly to either a phone or a reader. It reads tissue glucose levels constantly and reports its data to the device or your choice as well as to an internet portal where your veterinarian can access it. The sensor set up lasts up to 2 weeks and typically costs less than an in-house glucose curve run in the hospital. This is a fantastic option when it is time to get get a glucose curve. If one simply wants to spot check a glucose level, one will need a glucometer and you will need to be able to take a blood sample from your pet.

Many pet owners like to check glucose levels prior to insulin injections on a daily basis or simply want the ability to check a glucose level if there is a concern for hypoglycemia. For these situations, a glucometer is needed. Human meters can be obtained at any drugstore but we recommend getting a veterinary meter as the calibration is different. AlphaTrak is a popular brand but there are presently several other brands available.

The meter kit will contain measuring strips, solutions for calibration, and a spring-loaded lancet device for taking blood samples (usually from the ear margin). For details please visit the Diabetes Monitoring section of this library. Taking single drop blood samples turn out to be easier than you might think and video links are provided in the monitoring section. Still, not every pet is amenable to blood sampling and we do not want anyone getting bitten or scratched.

If you choose to use a glucometer at home, be sure to keep a log of when your pet was fed, when insulin was given, and what the glucose levels were that you found. (There are many phone apps to assist with this). Bring this log to your veterinarian when you come for check ups. Glucose levels obtained prior to the first insulin administration of the day are particularly useful. Your veterinarian will also be particularly interested in signs associated with poor regulation: excessive thirst, excessive urine production, excessive appetite, and weight loss.

The most serious problem to watch for is hypoglycemia (low blood sugar). This results from a mismatch in food consumption and insulin dose. If the dose is too high you can get hypoglycemia. If the pet doesn't eat, you can get hypoglycemia. Your pet may look simply tired, weak, or sleepy. If he/she is roused, he will seem drunken or may not be able to fully come to alertness. This can be an emergency and can progress to seizures so it is good to know what to do at home to prevent disaster.

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. The sugar will absorb directly from the mouth; swallowing is not necessary. 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.

It is best to know that your pet has recently eaten before giving the scheduled insulin dose.

(original graphic by marvistavet.com)