Dogs: Diagnosis and treatment of diabetes mellitus

Treating diabetes complicated by ketoacidosis

Diabetic ketoacidosis (DKA) is a potentially life-threatening complication of diabetes mellitus that has to be aggressively treated.

Diagnosis

The diagnosis is based on the presence of ketonuria with signs of systemic illness.

Treatment guidelines

Goals of treatment include the correction of fluid deficits, acid-base balance and electrolyte balance, reduction of blood glucose and ketonuria, and beginning insulin therapy and treatment of concurrent diseases.

Many protocols for treatment exist but rapid-acting insulin (regular) must be administered first, as decreases in the hyperglycemia must be achieved quickly. When blood sugar levels are lowered and maintained at 200−250 mg/dL for 4−10 hours, then Vetsulin® (porcine insulin zinc suspension) can be used.

Evaluation of treatment

When evaluating the regulation of insulin therapy, it is important to consider several areas including the evaluation of glycemia, urine monitoring, routine rechecks and glycated protein evaluations.

Evaluation of the glycemia

Creating a blood glucose curve is the most accurate way to evaluate glycemia in order to adjust the dose of Vetsulin.

Indications for creating a blood glucose curve are:

  • First, to establish insulin dose, dosing interval and insulin type when beginning regulation.
  • Second, to evaluate regulation especially if problems occur.
  • Third, when rebound hyperglycemia (Somogyi) is suspected.

Contraindications for creating a blood glucose curve are:

  • Concurrent administration of drugs affecting glycemia.
  • Presence of a known infection or disease.
  • Stressed animal.

The procedure is as follows:

  • The most accurate way to assess response to treatment is by generating a blood glucose curve. Ideally, the first sample should be taken just prior to insulin administration. Alternatively, after the dog has been given its first meal followed by the Vetsulin injection in the morning, the first blood sample should be taken as soon as possible. Thereafter, blood samples should be taken every 2 hours for 12, or ideally, 24 hours.

For punctual blood glucose measurements, collection of single blood samples late in the afternoon, shortly before the second meal is fed can be done. However, this is less precise as some problems could be missed (eg, Somogyi overswing).

Urine monitoring

Urine only tests positive for glucose if the blood glucose concentration remains above the renal threshold for a substantial period of time. Urine monitoring, therefore, is not a very reliable method by which to adjust a dog's insulin dose. This method should only be used when it is impossible to take blood samples.

Routine rechecks

After the animal has been stabilized successfully, routine rechecks should be done at regular intervals (2−4 months) on regulated animals. Recheck evaluations sometimes reveal slight hypo- or hyperglycemia and if all other parameters (urine, appetite, water uptake, general conditions, etc.) are normal, repeat testing of the glucose the following day is recommended before any adjustment of the dose is made.

Glycosylated proteins

Measurement of glycosylated proteins (serum fructosamine [SF] and glycosylated hemoglobin [GHb]) is another way of evaluating regulation. The level of these proteins reflects the chronic hyperglycemia characteristic of diabetes mellitus and is not affected by stress, medication or recent feeding. SF is most frequently used and reflects the mean blood glucose for the regulation for 2−4 weeks before the blood sampling. This test is available through most diagnostic laboratories and results should be interpreted according to each laboratory's guidelines.