Diabetes mellitus is a diseased state by which the body suffers from either an absolute shortage of insulin (Type I), or from an incorrect response from the cells to the insulin that is being produced, a condition termed insulin resistance (Type II). Both of these conditions will prevent the muscles and organs from converting glucose to energy, and will result in excessive amounts of glucose in the blood, which is also referred to as hyperglycemia.
Diabetes is a disorder of carbohydrate, protein, and fat metabolism caused by an absolute or relative insulin deficiency. Metabolism refers to how the body digests and uses food for growth and energy, and this process is largely dependent on a sufficient amount of insulin in the body.
Insulin is a hormone that is produced in the pancreas, releasing into the cells in response to the digestive conversion of proteins into glucose in the bloodstream. Much of the food that is ingested is broken down into glucose, a type of sugar in the blood and one of the body's main sources of energy. Appropriate insulin function will trigger the liver and muscles to take up glucose from the blood cells, converting it to energy.
Diabetes, a common condition for humans, is also relatively common in domestic animals like dogs. Type I diabetes is the more severe form of the disease, as it is dependent on daily insulin injections for maintaining blood sugar balance (insulin dependent diabetes mellitus – IDDM).
An affected dog will be hungry a lot of the time, since glucose is not making it to the brain; glucose levels in the brain are too low for the brain to register that it is receiving food. Because insulin is not giving the muscles and organs the signal to convert glucose to energy, the excess glucose in the blood will be carried out of the body in urine instead of being used for energy, and there will be a concurrent lack of energy. There is also increased thirst as a result of the increase in urine. The liver is adversely affected by this condition, as are the eyes and kidneys.
At heightened risk are obese dogs and female dogs. While many cases of diabetes are seen in older dogs, it can occur at any age.
Symptoms and Types
- Excessive urination
- Excessive thirst
- Weight loss even with normal appetite
- Anorexia – complete loss of appetite
- Lethargy and depression
Development of Ketoacidosis – metabolic acidosis caused by the breakdown of fat and proteins in the liver in response to insulin deficiency
- Enlarged liver
- Bladder or kidney infection
There are several possible causes for diabetes mellitus. Genetic predisposition is one likely cause, since some breeds seem to be predisposed to diabetes, and dogs that have diabetes often also have relatives with it. However, there is also thought to be a relation to hormones therapies, since dogs that are receiving drugs to control heat cycles are at a higher risk for developing diabetes. This is due to their interference with insulin production. Pancreatitis is also likely to be a factor.
Some causes that are still being investigated are immune-system disorders, and there are indications that viral diseases can also lead to this condition. The prevalence of diabetes in dogs is not great; it varies between one in 400 and one in 500.
The following breeds are at a higher risk:
Your veterinarian will take detailed medical history from you of your dog's health leading up to the onset of symptoms and details of the exact symptoms. Standard tests will include a complete blood count, chemical profile, and urinalysis. These tests should be sufficient for diagnosis and initial treatment.
Typically, with diabetes, an unusually high concentration of glucose will be found in the blood and urine. Abnormally high levels of liver enzymes and electrolytes imbalances are also common. Urine test results may also show evidence of abnormally high levels of ketone bodies - water-soluble compounds produced as a by-product of fatty acid metabolism in the liver and kidney. A numbers of other abnormalities may also be found.
Radiographic studies, including x-rays and ultrasonography, can be helpful for the diagnosis of concurrent diseases and complications due to diabetes. Abdominal X-rays and ultrasound will help to determine the presence of kidney stones and/or inflammation of the pancreas and liver, as well as other associated abnormalities. In the case of liver disease, should it appear suspect, your veterinarian may decide to take a sample of liver tissue for further diagnostic evaluation.
Treatment and Care
Your veterinarian will prescribe a course of treatment that will include daily exercise in your dog’s schedule. Lowering insulin demands and balancing your dog's food and liquid cravings to healthy levels will be the first priority. Obesity is one of the major risk factors for diabetes, and this condition can make management of diabetes difficult, but it can only be brought under control slowly and with great care. The target weight may be reached in 2-4 months, but your veterinarian will need to suggest a practical time line that is appropriate for your dog. If your dog has actually lost weight, you will need to work with your veterinarian on a plan to increase your dog's weight to normal levels.
Soft and moist foods will have to be avoided because they cause rapid accumulation of glucose in the body. However, do not change your dog food suddenly and without first discussing it with your veterinarian. Your dog will need a well-thought out and strictly enforced diet plan. Your veterinarian can help you to design a plan that is well suited to your dog's needs, with life-style changes to facilitate proper management of the diabetes.
Most patients' diabetes can be managed without complications, but for some dogs the situation may be more challenging. Your veterinarian will make an individual treatment and management plan for your dog based on the dog's current disease status. Your veterinarian will also brief you on what to look for in case of eitherhypoglycemia (low levels of glucose) or hyperglycemia (high level of glucose), both of which can be seen in diabetic dogs. Keeping a daily and weekly chart of your dog's diet, glucose test results, daily insulin dose, and weekly body weight is highly recommended for following patterns and recognizing when your dog deviates from it's regular pattern. There are various types of insulin available and a selection of the type that is appropriate to your dog will made by your veterinarian.
For instance, smaller dogs usually need multiple doses of insulin as part of their daily insulin therapy, while larger dogs may only need one dose per day. Likewise, doses are calculated according to the weight, age, gender and individual insulin requirements of the affected dog. Depending on how severe the diabetic condition is, and how the amount of insulin in the body variates from day to day, you may need to evaluate your dog's blood glucose levels on a daily basis and adjust the insulin dose accordingly.
If this is a serious issue, and there are no plans to breed, your veterinarian will recommend a hysterectomy for your female dog. This is to avoid the surge of hormones at the time of estrus, which can further complicate your dog's health. Unfortunately, this is not a disease that will be cured, but your dog's health can be kept stable and it can go on to live a fully enjoyable life. This will be dependent on your willingness to adhere to your doctor's dietary recommendations. If properly managed, diabetic patients do well and usually have normal life-spans. The best preventive from complications is practicing careful maintenance.