Insulin is produced in the pancreas, which is located along side the small intestine, near the stomach. The pancreas also produces and secretes digestive enzymes into the small intestine to help in the digestion of food.
The cells of the body require a sugar known as glucose for food. To absorb and utilize glucose, the cells need the hormone, insulin. It basically unlocks the cell walls so that the glucose can enter and provide the cells the energy they need to work. Glucose comes from the diet. The food is broken down into parts, including protein and carbohydrates. If the animal does not have food, the body must break down fat, stored starches and protein to provide energy for the cells. Proteins and starches can be converted into glucose but fat is broken down into ketones. Ketones can be uses for energy in a emergency by the body but too much ketones in the blood can be very unhealthy.
In a diabetic animal there isn’t enough insulin.
The cells cannot receive glucose from the blood because there is no insulin to allow the cell to absorb it.
The cells then tell the body that they are starving. They can’t recognize that there is plenty of glucose in the bloodstream.
Protein, starch and fat are broken down from the body’s stores to help with this perceived starvation. This elevates the level of glucose in the blood even more and it also starts to build up the level of ketones in the blood.
Normally, the kidneys do not allow glucose to be lost in the urine. When an animal is diabetic, there is so much glucose in the blood that the kidneys are overwhelmed and the glucose spills into the urine and is lost. Glucose draws water with it into the urine which leads to excessive urine production and then the body becomes thirsty as it needs to keep up with the extra fluid loss.
Thus the main signs of diabetes are:
- Excessive eating
- Excessive drinking
- Excessive urination
- Weight loss
How is Diabetes Mellitus diagnosed
Diabetes is diagnosed by a blood and urine test. Usually the blood test shows a dramatic increase in blood glucose and also glucose in the urine. Blood glucose levels can fluctuate rapidly depending on time of meals and also can be elevated with stressful situations (like getting blood drawn at the veterinary hospital). If there is any uncertainty over the blood glucose value, a test called fructosamine can be requested. This test reflects an average blood glucose level over the past few weeks and can then distinguish a one-time elevated blood glucose from persistent elevations seen in diabetes. Urine testing can also check for evidence of ketones, which indicates to a certain extent the severity of the condition, and also will detect any urinary tract infections, which are more common in diabetic patients.
Type I and Type II Diabetes Mellitus
Diabetes in humans is broken down into two forms: Type I and Type II. These are also called juvenile onset and adult onset diabetes. Type I is the type where the pancreas produces no insulin at all and type 2 the pancreas produces some insulin but not enough. Most dogs have a type I diabetes where the pancreas for some reason does not produce any insulin. Most cats have a diabetes similar to the adult-onset type in people. In some cases, cats may be able to resolve their diabetes but in both cats and dogs, most patients will require insulin treatment for life.
Cause of Diabetes Mellitus
The exact cause of this disease in unknown in many cases. It can be related to an autoimmune disease, genetics, obesity, chronic pancreatitis, certain medications and abnormal protein deposits in the pancreas. Some breeds seem to be at a greater risk, including Australian Terriers, Standard and Miniature Schnauzers, Dachshunds, Poodles, Keeshonds and Samoyeds. Juvenile diabetes is prevalent in Golden Retrievers and Keeshond and obese dogs and female dogs may run a greater risk of developing diabetes later in life. The Burmese is the only predisposed feline breed. In cats it is believed that Diabetes is often related to an insulin resistance and glucose toxicity, although decreased production of insulin can also be found.
How is Diabetes Mellitus Treated
In most cases, diabetes patients will need insulin injections, just like in people. Insulin cannot be given orally because the stomach acid would destroy the hormone before it could be absorbed into the bloodstream. Also, the insulin injections most often need to be given twice a day, approximately 12 hours apart. Owners need to learn how to give insulin injections to their pets. The injections are given under the skin, or subcutaneously. It is not difficult to learn, the needles are very small and most pets will not mind the injections. In the first few weeks of treatment it may take a few blood sugar tests to determine the best dose. Sometimes these tests can be just at peak times, to get a general idea of how the blood sugar is doing, and sometimes a 10 – 12 hour blood glucose curve will be needed. This test takes samples of blood every 1-2 hours through the day to see how much of a response the patient has to the insulin and how long that response lasts. Finally, most patients are monitored periodically with either blood glucose or fructosamine tests to make sure there are no problems arising or dose changes required. Insulin doses should never be altered without a doctor’s advice.
If Diabetes is left untreated or unregulated it can cause complication in many parts of the body. In dogs, sugars can enter the lens of the eye causing cataract formation. Diabetic animals may be more susceptible to urinary tract infections.
What to Watch For
Diabetic patients should be rechecked if any of the following signs occur:
- if they seem to feel ill
- if they are losing weight
- if they have either a ravenous appetite or loses their appetite
- if they are drinking or urinating excessively
- if they become disoriented or groggy
After an increase in insulin dose or if the patient is not eating well, a low blood sugar level is a concern. An insulin overdose can result in blood sugar levels dropping too low. The signs of too low blood sugar are lethargy, weakness, restlessness, shivering, convulsions or seizure. Low blood sugar can be much more dangerous than high blood sugar and should be treated immediately. If low blood sugar is suspected, it is important to try to get the pet to eat. If they will not eat, you can give Karo syrup, honey or sugar water . If there is no improvement, they should be seen by your veterinarian immediately.
Problems with Regulating Insulin Dose
Some pets can be difficult to regulate. There may be an underlying reason to sort out. Conditions such as urinary tract infections can make the body more resistant to the effect of insulin. The hormone progesterone can also interfere with insulin so intact female diabetic patients should be spayed. Certain drugs, such as steroids can interfere with the insulin as well. Improper administration or handling of the insulin can be a problem with regulation. If there are any concerns about this the veterinarian can give advice and demonstrations to ensure that things are done effectively. Some patients have different rates of insulin metabolism and may need a different insulin type to help become properly regulated. Insulin overdosage can actually lead to an elevated glucose level. The body will try to compensate to a low blood glucose by breaking down stored energy and causing a rebound high blood sugar level.
It is important to try to give the insulin at the same time each day and feed meals in conjunction with the insulin. This allows the increased nutrients in the blood after a meal to coincide with peak insulin levels.
Feeding a Diabetic Pet
Regulation is achieved via a balance of diet, exercise, and insulin. In cats, the most beneficial diet is one that is low in carbohydrates and high in protein. In dogs, it is recommended to use high fiber diets which help to slow down the release of sugar into the bloodstream. Foods such as breads or sweet treats should be avoided.