Diabetes Mellitus

25 Diabetes Mellitus

10. What is the recommended protocol for initiating treatment for diabetes mellitus?

The intermediate-acting insulins, lente insulins, and neutral protamine Hagedorn (NPH) insulins, are recommended for initial management of diabetes mellitus in dogs. The duration of action of lente insulin is slightly longer that of NPH insulin in some dogs. Although the structure of porcine insulin is identical to that of canine insulin, recombinant human insulin can be used successfully as well. Insulin analogues, such as glargine insulin, can be used in dogs, but advantages over other insulins have not been reported. The author currently recommends porcine lente insulin or human recombinant NPH insulin for initial treatment. Twice-daily administration of insulin provides better control than once-daily administration in most dogs, although once-daily insulin administration is effective in some dogs. Because insulin requirements vary considerably between individuals, a conservative initial dose of 0.5 U/kg is recommended. It is recommended that two to three blood samples be obtained 4 to 8 hours after the initial injection to evaluate for hypoglycemia. If hypoglycemia is not present, the dog is discharged to the owner after it has been ascertained that the owner has been thoroughly educated about the disease process, possible complications (cataracts, hypoglycemia), how to monitor the clinical response to insulin, and how to handle and administer insulin. An appointment to assess response to treatment is scheduled for approximately 1 week after discharge.

12. How is the response to insulin treatment monitored?

A combination of clinical signs, physical examination findings, and blood glucose determinations is used to assess the response to treatment of diabetes in dogs. An observant owner is often able to assess the response to treatment by monitoring the dog’s activity level, water consumption, urination, and strength. Assessments based on these observations have been shown to be similar in accuracy to assessments based on other measures. It is useful to have owners of diabetic dogs document their assessments on a standardized form, so they can provide a consistent and complete history of the dog’s response to treatment. Stable or increasing body weight, improved quality of hair coat and skin, and improved muscle mass are indications of good control of blood glucose levels. Glucose curves are a very useful measure of how well the diabetes is controlled, but do have some limitations. Stress response or inappetance can invalidate the glucose curve and there is substantial variation from day to day in an individual dog, so the information gained from a glucose curve must be interpreted in light of other measures of glycemic control.

Follow-up visits are scheduled for the morning. For the initial follow-up visit, the owner is instructed to feed the dog as usual but to wait to administer the insulin injection until the office visit. At the visit, the owner administers insulin under observation by the veterinarian or technician, so that any problems with insulin handling and injection can be addressed. For subsequent follow-up visits, the owner is instructed to feed the dog and administer the insulin at home as usual prior to the appointment. A blood glucose curve is obtained by measuring blood glucose concentration every 2 hours for 8 to 12 hours after administration of insulin. Most handheld glucometers are sufficiently accurate for this purpose, and the stress of obtaining the sample can be minimized by using a lancet to collect capillary blood from the inner surface of the pinna. Some owners may be able to perform this procedure at home, but substantial training is necessary to ensure accurate results.

14. What can be learned about blood glucose control by evaluating a glucose curve?

The blood glucose concentration at its nadir and the duration of effect of the insulin are the most important information that can be learned from a glucose curve. The nadir is the lowest glucose concentration obtained during the sampling and ideally should be between 100 and 150 mg/dl. If the nadir is below 80 to 100 mg/dl, the insulin dose should be reduced and if it is greater than 150 mg/dl the insulin dose should be increased. The amount by which the insulin dose should be altered depends on the degree to which the nadir varies from the ideal. If the nadir is higher than desired, an increase in the insulin dose by 1 to 3 units is indicated.

The duration of insulin effect is the time that the blood glucose concentration remains below 250 mg/dl. The optimal duration of effect for a dog receiving once-daily insulin injections is 22 to 26 hours, while the ideal duration with twice-daily dosing is 10 to 14 hours. If the duration of effect is inadequate, administration of a longer-acting insulin is necessary. If the duration of effect of insulin administered once daily is inadequate, administering that insulin twice daily is usually sufficient. When switching from once- to twice-daily insulin administration, the once-daily dose should be reduced by 25%. Lente insulin can be administered if NPH insulin is of insufficient duration. If lente insulin administered twice daily has too short a duration of effect, protamine zinc insulin (PZI) or ultralente insulin may be administered. About 1 week after a change in insulin dose or formulation, another assessment of clinical signs should be performed and a glucose curve should be obtained and the dosage of insulin should be adjusted if necessary, as just described.

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Jul 31, 2016 | Posted by in INTERNAL MEDICINE | Comments Off on Diabetes Mellitus

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