There are actually several diseases/syndromes that begin with the word diabetes—we’re going to discuss diabetes mellitus. Lets start with some basic underlying physiology.
The pancreas is an L shaped gland that sits near the stomach and the first part of the small intestine. It produces digestive enzymes that empty into the small intestine and insulin that is secreted into the bloodstream to help the body bring glucose into cells. In diabetes mellitus there is not enough insulin to perform that job and the body feels like it is starving even though there is lots of glucose (sugar) circulating. The body begins to break down body stores of protein, carbohydrate (sugars) and fat. There is lots of glucose circulating and the kidneys can’t filter it out. Sugar begins to spill into the urine and as a result water follows this molecule. This leads to excess thirst and urination usually seen in unregulated diabetic animals. This glucose in the urine also makes a great place for bacteria to set up housekeeping so diabetics frequently have bladder infections as well. In addition, in more advanced cases the breakdown products from fat metabolism cause ketones to build up in the blood and spill into the urine. Ketones wreak havoc on the ph levels of the body and cause a more serious form of diabetes called diabetic ketoacidosis. Ketones are detected in the urine along with glucose and the patient is typically much sicker at this stage of the disease.
The symptoms we typically see with diabetes mellitus are excessive appetite/eating, excessive thirst/drinking, excessive urination, and weight loss. In cats we can also see walking with dropped hocks that can signal early weakness from diabetes.
To make a diagnosis the signs are not enough. Other disease processes can mimic these symptoms. We need the history, a physical exam, bloodwork and a urinalysis. Cats can have a stress glucose elevation in the blood and often we add an additional test called a fructosamine to differentiate between stress hyperglycemia (high blood sugar) and true diabetes.
Once we make the diagnosis, treatment varies based on how ill the patient is, are they ketoacidotic, do they have a bladder infection, etc.
An uncomplicated diabetic is one who has no ketones, no infections, and is typically early in the course of the disease. In those cases we start them on one of several possible forms of insulin injections. Most patients require hospitalization in the initial phase of regulation so we can check frequently for too rapid drops in blood glucose and electrolyte changes.
In those animals who are sicker with infections, ketones, and depression—those patients need more aggressive intervention which can include repeat bloodwork, intravenous fluids, repeat urinalysis, antibiotics, and more intense monitoring and hospitalization sometimes for several days to stabilize them.
To treat diabetic patients long term, once that patient is stable, they need insulin injections. Dogs will need insulin typically twice a day for the rest of their lives. Some cats, if we catch the disease early enough, will need insulin for a period of time and can sometimes begin to produce enough insulin on their own again and go off the injections. A prescription diet makes managing this problem much easier in both dogs and cats.  If possible we want to feed the patient the same amount of food twice a day and the insulin following the meal. It’s important not to give these diabetic patients food or treats in between meals. Each time they eat, their blood sugar goes up. The insulin follows to bring that glucose level down. We want to keep the glucose levels within a narrow normal range if we can. When you feed treats or other meals at additional times during the day this causes an elevation out of this range and can cause a return of symptoms and further problems. It is also wise not to feed the semi-moist pouches of food as these foods have more sugar in them.
Most owners are intimidated by the idea of giving their beloved pets an injection twice a day. Insulin syringes have extremely tiny, thin needles and I have yet to see a patient who seems to react to the injection. Its is much easier than it sounds and most people can master this task with a little instruction when we show them how to do it and how little their pet minds the process.
Long term monitoring requires blood glucose checks and typically rechecks of urine as diabetics are very prone to bladder infections and infections in general. Exercise, diet, stress, and infections can all affect glucose levels and insulin needs. Things can change over time even when everyone is doing everything right and sometimes patients have problems that need to be addressed. It is a commitment in time and attention to detail to keep these patients as healthy as we can. They do best when they get meals and insulin roughly 12 hours apart every day. So when clients want to leave on vacation or even short trips, its vital that someone can take care of these patients and continue to medicate and feed them on a routine schedule.
Insulin needs to be handled gently and not shaken. If shaken it destroys the delicate insulin molecules and becomes inactive. Typically a bottle of insulin will last a patient 6-8 weeks if handled correctly. Your veterinarian has several insulins to choose from and that needs to be addressed on an individual case basis.
Once your diabetic pet is regulated and on a schedule these are things to watch for that could signal a problem that needs to be addressed. If your pet begins to lose weight again, begins to drink or urinate excessively, seems to feel ill, has a ravenous appetite, becomes disoriented or depressed or groggy, have that animal checked quickly. If your pet seems wobbly or drunken, the blood sugar level may be too low. This would occur if too much insulin is given or the regular dose is given without the animal eating its regular meal or only part of its meal. Try to feed the pet if they are alert enough to swallow but if that is not possible or if the patient seizures, take a little Karo syrup, orange juice, sugar water or honey and rub it on the gums in the mouth until the animal appears more alert (typically 1 tablespoon per 5 lbs). If this does not stabilize the patient seek immediate medical attention. If the animal does respond and seems more alert, try to feed the patient and have that animal checked preferably that day if possible.
Some pets can be difficult to regulate due to drugs used like forms of cortisone, the presence of hormones like progesterone (unspayed females), other health issues like Cushing’s disease or chronic sources of infections like severe dental disease just to name a few. Its important to identify these causes and correct the underlying problem to make regulation more effective.
Diabetes mellitus is a time consuming ailment that takes dedication to manage and it’s a lifelong problem unless you happen to be that lucky cat that is able to go off insulin with early, successful management. Your veterinarian can discuss the process in more detail but this overview gives you an idea of what this disease is and how we can keep our diabetic pets with us longer after diagnosis.
Dawn Hess, DVM
