How Diabetes is Diagnosed
The primary symptoms of insulin-dependent diabetes mellitus in dogs are increased thirst and water consumption, increased urination, increased appetite, increased food intake and weight loss. While the presence of these symptoms can lead to a tentative diagnosis of diabetes, in order to confirm the diagnosis the veterinarian must perform a number of tests to rule out other possible causes of the dog’s symptoms and to determine an appropriate course of treatment. Fortunately, diabetes mellitus is not particularly difficult to diagnose, and it is one of the more manageable metabolic diseases of companion dogs.
Dogs with diabetes mellitus cannot properly metabolize or use dietary sugars either due to insulin insufficiency or insulin resistance. Unprocessed sugars will build up in circulating blood, which is called “hyperglycemia.” Eventually, glucose will start to be excreted in the urine (this is called “glycosuria”). Hyperglycemia and glycosuria can easily be detected through simple blood and urine tests that can easily be conducted at almost any veterinary clinic. One of those tests involves fasting the dog for a period of time and then assessing a blood sample for its glucose levels. Dogs with fasting hyperglycemia probably have diabetes. Routine blood work (a complete blood count and serum biochemistry profile) can also help identify kidney or liver disease. Any detectable amount of glucose in a dog’s urine is abnormal and highly suggestive of diabetes mellitus.
Diabetes also causes the dog’s body to enter starvation mode. Because the dog is unable to process and use glucose normally, over time its body begins to break down and use stored proteins and fats for energy, so that essential bodily functions can continue. The breakdown of fat causes substances called ketones to build up in the dog’s blood and eventually be excreted in the urine. The presence of ketones in urine can also be detected by a urinalysis and is a very strong positive indicator for diabetes mellitus. Dogs with ketoacidotic diabetes mellitus are very sick and typically present with profound dehydration, weakness, depression, vomiting and signs of shock. This presentation, together with elevated blood and urine levels of glucose and ketones, are diagnostic of this stage of the disorder in almost all cases.
Most dogs that suffer from diabetes mellitus have an increased chance of developing urinary tract infections (UTIs), because the high level of sugar in their urine provides a good environment for bacterial overgrowth in the urinary tract. A simple urinalysis will let the veterinarian know whether the dog needs to be treated for a UTI.
Diabetes of any type is a serious disease that requires regular treatment and monitoring. Typically, diabetes mellitus can be effectively controlled through dietary management and insulin administration and regulation. Many people have diabetic dogs that lead happy, healthy and long lives, thanks to the diagnostic and treatment options that are now available.