Diabetes Mellitus (DM) is a chronic condition in which a deficiency of the hormone Insulin impairs the body’s ability to metabolize sugar. It is one of the most common endocrine (hormonal) diseases of cats and dogs. There are two types of diabetes mellitus: Type I DM occurs when the body does not produce enough insulin; therefore insulin injections are required to control the disease. Dogs nearly always (99%) have the type I variety while approximately 50 to 70% of cats are diagnosed. Type II DM occurs when the pancreas produces enough insulin but something interferes with its ability to be utilized by the body. Type II DM is less common and is identified in approximately 30% of cats. It is treated with dietary management, weight control, and oral drugs.
Diabetes mellitus usually affects middle-aged to older cats and dogs. It is most common in female dogs and neutered male cats. Juvenile-onset diabetes may occur in cats and dogs less than 1 year of age. Any breed of cat or dog can be affected. Dog breeds at increased risk include: Australian terriers, Samoyeds, Schnauzers (miniature and standard), Bichon frises, Cairn terriers, Keeshonds, Spitzes, Fox terriers, and Poodles (miniature and standard). Risk factors for diabetes mellitus include: obesity, recurring or previous pancreatitis, Cushing’s disease, and drugs such as glucocorticoids and progestagens that antagonize insulin.
In order to understand the problems involved in diabetes mellitus it is necessary to understand something of the normal body’s metabolism. The cells of the body require sugar (glucose) as food and they depend on the bloodstream to bring glucose to them. They cannot, however, absorb and utilize glucose unless a hormone, Insulin, is present. Insulin is produced by the pancreas.
Glucose comes from the diet. When an animal goes without food, the body must break down fat, stored starches, and protein to supply calories for the hungry cells. Proteins and starches may be converted into glucose. Fat, however, requires different processing which can lead to the production of ketones rather than glucose. Ketones may be detected in the urine of starving animals as massive fat mobilization is required for ketone formation.
In the diabetic animal, there isn’t enough insulin. The cells cannot receive glucose from the blood because there is no insulin to permit it to be absorbed and utilized. The body is unable to detect the glucose present in the blood and is fooled into thinking starvation is occurring. Protein, starch, and fat breakdown occur as in starvation. Yet, all along there has been plenty of glucose in the blood; in fact, by now, there is a large excess of glucose in the blood as all resources have been mobilized. The normal kidney is able to prevent glucose loss in urine. In the diabetic animal, there is so much glucose in the blood that the kidney is overwhelmed and glucose spills into the urine and is lost. In severe cases, ketones are also found in the urine, a more complicated diabetic emergency, known as Diabetic Ketoacidosis (DKA). Glucose is able to draw water with it into the urine. This leads to excess urine production and excess thirst to keep up with the fluid loss in excess urine production.
Clinical Signs/What to Watch For:
- Increased thirst/Excessive drinking
- Increased frequency and/or amount of urination
- Weight loss despite a good appetite
- Poor body condition/poor haircoat
- Weakness in cats – especially in rear legs
- Sudden blindness due to cataract formation in dogs
*Another common issue with diabetes mellitus is urinary tract infection. All the sugar in the urine makes the bladder an excellent incubator for bacteria. Antibiotics are often necessary to clear up any infections and some future monitoring is advised to help detect them.
Veterinary care should include diagnostic tests to determine the underlying cause of any clinical signs you are seeing in your pet. Your veterinarian will ask questions about your pet’s medical history and perform a thorough physical exam. Routine bloodwork can help screen for any metabolic disease, and also help diagnose diabetes. A CBC (complete blood count) and Chemistry panel (serum biochemical analysis) can determine the blood glucose concentration and exclude other potential causes of the same symptoms. A urinalysis is also done to check for glucose and any evidence of a urinary tract infection. Other diagnostic tests, such as abdominal radiographs (x-rays) or abdominal ultrasound (US) may be done if complications or concurrent diseases, like pancreatitis (inflammation of the pancreas), are suspected.
Most dogs and cats will require twice daily injections of insulin to control their blood glucose. These injections are given under the skin using a small needle. Most dogs and cats become readily accustomed to the treatments. Your veterinarian’s office will train you thoroughly in the proper use of insulin and subcutaneous injection techniques. Proper weight management, and regular exercise, in combination with therapeutic diets can aid in the control of diabetes. Ovariohysterectomy (spaying) is indicated in female diabetic animals to reduce the effects of estrogen on diabetes and insulin.
Complications such as urinary tract infections may require additional medications, but certain drugs (e.g. steroids like prednisone) should be avoided in diabetic patients. Prepare for frequent adjustments to therapy early in the course of treatment. Veterinarians prefer to start with a low dose of insulin initially and adjust upwards slowly to avoid overdosing. Your veterinarian may recommend hospitalization to measure the blood glucose every few hours (this is known as a glucose curve). Insulin overdose may cause low blood glucose (hypoglycemia), potentially resulting in disorientation, weakness, or seizures (convulsions, tremors). If you notice any of these symptoms in an otherwise responsive cat or dog, offer food immediately. If the cat or dog is unconscious, Karo syrup can be applied to the gums. In either case, call your veterinarian as soon as possible.
While there is no way known to prevent type I diabetes mellitus, proper weight management can reduce the likelihood of your dog or cat developing type II diabetes (which is the most common).
Please call us at 706-546-7879 if you are interested in having your pet screened for diabetes. You can also visit our website at www.hopeamc.com for more information. We here at Hope Animal Medical Center hope you have a very Happy Thanksgiving!