Managing diabetes complicated by ketoacidosis
Diabetic ketoacidosis (DKA) is a potentially life-threatening complication of diabetes mellitus that must be swiftly and aggressively treated.
Diagnosis is based on the presence of ketonuria with clinical signs.
Goals of treatment for diabetic ketoacidosis include correcting fluid deficits and acid-base and electrolyte imbalances, reducing blood glucose and ketonuria, initiating insulin therapy, and treating concurrent diseases. The use of intravenous fluid therapy with isotonic fluids to correct fluid deficits and acid-base and electrolyte imbalances is recommended.
Many protocols for treatment of DKA exist but IV fluids and rapid-acting insulin (regular) must be administered first to quickly decrease hyperglycemia. Once the blood glucose has decreased to 250 mg/dL using regular insulin, it is important to add dextrose to the fluids and continue with regular insulin until the cat is no longer vomiting, is eating, and no longer has ketones in the urine. At this point, the regular insulin along with the dextrose in the fluids can be discontinued and Vetsulin® (porcine insulin zinc suspension) therapy can be initiated.
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 to adjust the Vetsulin dose.
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 you suspect rebound hyperglycemia (Somogyi effect).
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 management response is to generate a blood glucose curve. Ideally, take the first blood sample just prior to or immediately following the first Vetsulin administration. Thereafter, take blood samples every 2 hours throughout the day for 12 hours.
For punctual blood glucose measurements, collect single blood samples late in the afternoon, shortly before the second meal is fed. However, this is less precise as some problems could be missed (eg, Somogyi overswing). For this reason, it is not recommended to increase the dose of Vetsulin based on a single blood glucose sample (spot check).
Urine only tests positive for glucose if the blood glucose concentration remains above the renal threshold for a substantial period of time. Therefore, urine monitoring is not a very reliable method by which to adjust a cat's insulin dose and should only be used when it’s impossible to take blood samples or to monitor for ketones in the urine.
After you’ve successfully stabilized the pet, do routine rechecks at regular intervals of 2 to 4 months. Recheck evaluations sometimes reveal slight hypo- or hyperglycemia and if all other parameters (urine, appetite, water uptake, general conditions, etc.) are normal, repeat glucose testing the following day is recommended before making any dose adjustment.
Measurement of the glycosylated proteins serum fructosamine (SF) and glycosylated hemoglobin (GHb) is another way to evaluate 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 regulation for 2 to 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.