Blood glucose monitoring

Editor's Note: In a continuing series of articles, DVM Newsmagazinehas teamed up with the American College of Veterinary Internal Medicine,(ACVIM) to bring you the latest in research abstracts on a variety of topics.Every month, an ACVIM diplomate will summarize, in abstract form, the latestresearch in specialty fields. These articles are coordinated with the helpof Dr. Ron Lyman, Ft. Pierce, Fla.

"Many inexpensive blood glucose monitoring systems have been usedby human diabetic patients for accurate assessments of their blood glucoselevels for many years.

Recently, pet owners have been using these devices on the ears of dogsand cats with diabetes to get immediate and accurate blood glucose sampleson their diabetic pets. This has improved quality of glucose regulationand accurate assessments of insulin requirements."

Management of diabetes mellitus in dogs and cats has always been a challengefor the pet owner and the veterinarian.

When an animal is first diagnosed with diabetes mellitus or developsa crisis due to dysregulation, pets are typically evaluated in a hospitalsetting, at which time glucose curves are performed from venous blood samplesat regular intervals to evaluate the animal's response to insulin. Oncean acceptable insulin dosage is determined, the pets are sent home to theirnatural environment, where the pet owner's subjective analysis (or an actualmeasurement) of the dog or cat's water consumption, appetite, weight, urineglucose and urine ketone levels and are used to determine glucose control.

Close monitoring of the pet's activity, diet and consistent schedulesare also very helpful in controlling or maintaining consistent blood glucoselevels at home.

Change over time

Because the patterns established from blood glucose curves done in thehospital, in a stressful and unnatural environment, are used to determinethe insulin dosage the pet will go home on, it is rare if the prescribedinsulin requirements do not change over time at home.

Insulin dosages are selected by assuming that the glucose curve is representativeof what occurs in the pet's body once it leaves the hospital. In fact, ithas been shown that there is a large variation in the day-to-day resultsof serial blood glucose curves in diabetic dogs.

This has very important clinical implications, especially when a singlepredetermined dose of insulin is prescribed based on such curves. (Proceedingsof the 19th ACVIM Forum, Abstract # 101).

Traditional monitoring of glucose control

Traditionally, the mainstay of home management of blood glucose and insulindosages involves the owner and veterinarian's interpretation of urine glucosemeasurements.

There has never been a debate about the disadvantages of urine glucosemonitoring.

For example, the urinary bladder can store urine for several hours; thereforeit is rarely an accurate reflection of blood glucose at a particular time.Obtaining a urine sample is not always a simple task, therefore is oftennot performed on a consistent basis. Monitoring urine glucose is virtuallyimpossible in an outdoor-only cat or in a dog or cat with primary renalglucosuria. (Schaer, M. A justification for urine glucose monitoring inthe diabetic dog and cat. J Am Anim Hosp Assoc 2001;37:311-312.)

Inability to differentiate hyperglycemia due to the Somogyi phenomenonvs. true hyperglycemia can be a deadly consequence of using urine glucoseas the daily determinant of glucose control. Nevertheless, when the clientis compliant and other monitoring parameters such as weight, degree of polyuriaand polydipsia, serum fructosamine levels and regular glucose curves inconjunction with urine glucose monitoring, it has been an acceptable methodof monitoring for many years.

At-home monitoring of blood glucose

For many years, inexpensive blood glucose monitoring systems have beenused by human diabetic patients for accurate assessments of their bloodglucose levels.

There is a trend developing in veterinary medicine: using a blood glucosemeter designed for human diabetics as a simple, rapid, pain-free methodof getting immediate and accurate blood sugars on diabetic pets. The advantagesof such a technique are clear: the pet is in its natural home environment,thus diminishing the role of stress on blood glucose values. Samples canbe obtained easily in dogs and cats using a device purchased in any pharmacyby performing a simple ear stick technique to obtain a blood sample. Repeatedsampling is easily performed. The results are a true measure of blood glucoseat the time of the test (Proceedings of the 19th ACVIM Forum, Abstract #100).

The test is simple to do and owner compliance is likely. The day-to-dayvariations of blood sugar in pets can be taken into account and insulindosages can be adjusted on a daily basis, if need be. These methods havebeen described and have improved quality of glucose regulation and accurateassessments of insulin requirements. (Reusch CE, Wess G, Casella M: Homemonitoring of blood glucose concentration in the management of diabetesmellitus. (Comp Cont Ed Pract Vet 2001;23:544-556.)

It is important to remember, however, that this testing method, althoughan excellent advancement in management of diabetes mellitus for veterinarypatients, should not be the sole method of evaluation.

The veterinarian should make treatment decisions with the client on aregular basis based on home blood glucose monitoring in and all other aspectsof diabetes management such as the patient's weight, degree of polyuriaand polydipsia, serum fructosamine levels, and some urine glucose and ketonemonitoring.