Causes of Diabetes Mellitus
Diabetes mellitus is a relatively common disease that results in an overabundance of glucose (a simple type of sugar) in the bloodstream and not enough glucose in the cells. Insulin, a hormone produced by the pancreas, normally helps transport the glucose from the blood into the cells. Diabetes may be caused by a deficiency in the amount of insulin produced because of poor development of the pancreas due to a hereditary defect or destruction of the pancreas by inflammation, viruses, or antibodies. Diabetes may also exist with normal pancreatic production of insulin if something destroys or interferes with the insulin. This situation may occur with certain drugs, hormonal diseases, and obesity.
Results of Diabetes Mellitus
Uncontrolled diabetes will cause an increase in water drinking and urination, and may lead to weight loss despite an increased appetite. Diabetes may result in urinary tract, skin, and mouth infections, cataracts, blindness, liver disease, pancreatitis, hair loss, heart failure, and reproductive abnormalities. Severe, uncontrolled disease may lead to coma and death.
The diagnosis of diabetes is based on history, physical examination, and blood and urine tests. Thorough testing for associated diseases is also necessary.
A stable diet of a specially formulated food is helpful in reducing and stabilizing the blood glucose. Snacks should be avoided. Dogs should be fed twice daily. Cats should have food available at all times, unless otherwise directed by your veterinarian.
Exercise will increase your pet’s use of glucose and will change the insulin requirement. With dogs, provide regular, moderate exercise instead of sporadic, more rigorous activity will make it easier to control the diabetes.
Oral hypoglycemic agents may be useful in a small number of cats. These medications are unpredictably effective and are only considered in select cases. Close monitoring of blood values and signs of illness is necessary.
Most dogs and cats with diabetes mellitus require daily injections of insulin to remain healthy. Despite some owners’ initial concerns about giving injections to their animals, most people soon become proficient at giving the insulin. Correct procedures for handling and administration of the insulin will be demonstrated.
The injection of the insulin will cause the blood glucose to decline over a period of time. Later, as the insulin decreases in your pet’s system, the blood glucose will increase again. Too little insulin will allow your pet’s blood glucose to stay too high and cause the problems associated with uncontrolled diabetes. Insulin that is given too infrequently may lower the glucose temporarily but will only work for part of the day. Too much insulin will cause the blood glucose to drop too low. When the glucose is too low (hypoglycemia), your pet may be quiet and hungry, but may become weak, appear drunken, seizure and possibly die. If you see these signs, rub some Karo syrup or similar high sugar substance on your pet’s gums, then offer food. Immediately consult your veterinarian concerning follow-up care and changes in the insulin dose. Strenuous exercise, decreased appetite, or illness while receiving the same amount of insulin may also cause hypoglycemia.
Some diabetic animals require hospitalization for stabilization and initiation of insulin treatment. During this time, a starting point for insulin dosage will be determined. Some animals will be started on a low dose of insulin given once daily, but most will require twice daily insulin.
There are many different types of insulin and your pet’s requirements are unique and will change over time. Close monitoring of your pet’s progress is essential to determine the correct insulin type, dosage, and frequency of administration. Click here to read more about Insulin Administration.
Blood glucose curve
The most accurate method for initial evaluation is blood glucose testing done in the hospital. A blood glucose curve involves frequent (usually every 1-2 hours) blood glucose measurements over 12 to 24 hours. This test allows us to determine the time of greatest activity, duration, and overall effectiveness of the insulin in your pet.
Glucose spot testing involves measurement of the blood glucose at the time of greatest effect of the insulin as determined by the blood glucose curves or typical duration of activity. The blood glucose spot tests and curves will be done as needed to ensure adequate control over your pet’s diabetes.
Fructosamine is a simple blood test that reflects average blood glucose concentration over the prior 2 to 3 weeks. This test measures the overall control of your pet’s diabetic state and is repeated every 3 to 6 months.
Monitoring Urine Glucose
Glucose will enter the urine when the blood glucose rises significantly above normal. Ketones may be present in the urine if your animal has had very high levels of blood glucose for a long time. It is the presence of glucose in the urine that causes the excessive urination and water drinking, as well as the tendency to develop urinary tract infections. With ideal control, diabetic animals may have blood glucose levels above normal, but not high enough to enter the urine. Unfortunately, most animals will have blood glucose levels above the ideal for some portions of the day. During these times, the urine will accumulate glucose and possibly ketones. Urine glucose concentrations will vary with the time of the last urination, the level at which your pet’s kidneys start to spill glucose, the amount of time the glucose is spilling into the urine, and how high the blood glucose was. Because of these factors, urine glucose is only an approximate measure of your pet’s diabetic state. Monitoring urine glucose is helpful, however, since it can be done at home. Your veterinarian will advise you on the procedure, frequency and timing of measuring the urine glucose and the action you should take depending on the results.
Routine Veterinary Care
Even with good control of the diabetes, your pet is at increased risk for infections and other diseases. We recommend an annual examination, (bi-annual for seniors), blood work, urinalysis, and urine culture be done every twelve months and a blood glucose curve or fructosamine every six months.