Dogs: Diagnosis and treatment of diabetes mellitus

Diagnosis and treatment overview

Diagnosis

Diabetes mellitus is not the only cause of polyuria/polydipsia and weight loss. Each dog should be examined thoroughly to rule out any other causes before starting insulin treatment. A preliminary diagnosis of diabetes mellitus based on clinical signs must be confirmed by blood and urine tests. Reference values for blood glucose range from 80−120 mg/dL (4.4−6.7 mmol/L) in dogs. The renal threshold is around 180 mg/dL (10 mmol/L). If the blood-glucose concentration exceeds this threshold, glucose is excreted in the urine.

Treatment

The goals in treating diabetes mellitus are to minimize the clinical signs of diabetes, the risk of hypoglycemia, and the development of long-term complications. Accomplishing these goals requires that pet owners understand all aspects of diabetes management. Investment of sufficient time in a careful explanation of all of the aspects of the therapy is strongly recommended.

Treating diabetes can be an exercise in frustration until stabilization occurs; however, there are tools available to help the veterinarian evaluate the disease and treatment, and there are resources available through this web site to provide additional support.

Insulin forms one of the cornerstones of the treatment of diabetes mellitus; therefore, it is important to understand the length of action of insulin, and how to evaluate treatment.

How to evaluate treatment
Many tools are available to evaluate treatment, including:

Monitoring blood glucose is a good way to evaluate regulation of the diabetic dog. It is, accurate, rapid and requires only a drop of blood. However, in certain conditions (see below), it is not reliable because blood glucose concentration is influenced by many factors. Consequently, blood glucose curves may not show the actual result of the insulin treatment.

Various factors such as economics, logistics, and clinical situations can also force veterinarians to limit diagnostic procedures. When it is not possible to perform a complete glucose curve, punctual blood samples combined with clinical signs, general observations and evaluating glycosuria can provide an overview of the diabetic animal. Veterinarians can also rely on evaluation of glycosylated hemoglobin (GHb) and fructosamine in laboratory testing.

Certain Conditions
Food intake, exercise, pet cooperation, use of a drug (eg, xylazine, demetomidine, prednisolone, progestogens, megestrol acetate), and other conditions (eg, hyperadrenocorticism, acromegaly) or stress can affect blood glucose levels. In these cases, therefore, blood glucose measurement will not be helpful and other methods of evaluation should be used.