Diabetes in dogs and cats is not a static disease and pets receiving insulin for the treatment of diabetes need to be monitored closely to insure a proper response to insulin therapy. Blood glucose curves are one of the most common and most valuable means of evaluating the efficacy of treatment and may be used to make changes in the insulin dosage or treatment schedule.
Performing a Blood Glucose Curve in a Diabetic Dog or Cat
Blood glucose curves are normally performed within 10-14 days of initiation of insulin therapy for most diabetic animals. This time period allows for equilibration of blood glucose levels and insulin levels. However, when glargine insulin is used, many veterinarians recommend performing additional blood glucose curves for the first three days of treatment because of the increased risk of hypoglycemia (low blood glucose) with glargine.
To perform a blood glucose curve, the normal insulin dose is administered and the time and dosage of insulin is noted. The first blood glucose reading should be performed directly before administering the insulin dosage or as soon as possible after the administration. If the blood glucose curve is to be done at the veterinary hospital, the pet owner may be asked to administer the insulin and feed the pet as normal before transportation to the hospital. Pet owners should always check with the veterinarian beforehand to get specific directions though.
After the insulin has been administered, the pet should have access to food and water as normal. Blood glucose readings should be measured every 1-2 hours until the glucose reading reaches 150 mg/dL or below, at which point readings should be obtained every hour until the glucose readings begin to increase again.
For pets who receive insulin twice daily, 12 hour blood glucose curves are sufficient as long as the blood glucose readings are increasing at the end of the 12 hour period. For those pets receiving insulin only once daily, blood glucose curves must be performed over a 24 hour period.
When beginning insulin administration for a newly diagnosed diabetic dog or cat, the veterinarian may also recommend measuring the fructosamine level after approximately 10-14 days of insulin administration as an additional monitoring test. Many veterinarians recommend periodic fructosamine levels for diabetic pets as an adjunct to the blood glucose curve.
Information Provided by Blood Glucose Curves for Pets with Feline and Canine Diabetes
Blood glucose curves safely and effectively allow the evaluation of the efficacy of the insulin dose being administered and allow veterinarians to make informed choices about increasing or decreasing insulin dosages, changing the scheduling of insulin administration, or changing the type of insulin administered.
In canine and feline diabetes which is being treated with insulin, blood glucose curves can be used to determine:
- whether the insulin is being absorbed properly, which may indicate that further investigation of administration techniques or storage of insulin is needed.
- onset of action of insulin (how long it takes the insulin to begin to work).
- the blood glucose nadir (the lowest glucose reading obtained). The glucose nadir corresponds to the peak of insulin activity. If the nadir is too low, a hypoglycemic crisis may be initiated which may become life-threatening for the diabetic cat or dog.
- the blood glucose delta (the difference between the highest glucose reading and lowest glucose reading). If the delta is too wide, it may indicate that a different type of insulin may be in order.
- fluctuations in glucose for the individual patient.
- the duration of action of the insulin (how long the insulin remains effective).
Performing Blood Glucose Curves at Home for Cats and Dogs with Diabetes
Once the diabetic dog or cat is stabilized, performing a blood glucose curve at home may be preferable to hospitalization in order to perform the curve. At home testing eliminates the stress associated with a hospital visit and may allow more accurate measures of blood glucose for many animals.
Blood glucose curves are easily performed for most dogs and cats. Pet owners can be easily taught to locate the vein along the margins of the ears and obtain a small sample of blood from these veins using a small needle prick. Glucometers, such as the Alpha-Trak® monitor, require only a very small sample of blood to measure blood glucose and are generally reasonably accurate.
Once the pet owner has successfully obtained the blood glucose readings, the values can be supplied to the veterinarian for evaluation. Dog and cat owners should not attempt to make insulin dosage changes without consulting their veterinarian, however.
Keeping a Diary to Monitor the Progress of Diabetic Pets
Dog and cat owners treating a pet for diabetes should also keep a diary of their pet's progress. The daily diary should include:
- the date,
- the time of insulin administration,
- the dosage of insulin administration,
- the activity level of the pet,
- bowel movements (form, consistency, color),
- the amount of urine (approximated by number and size of clumps in litter),
- the amount of food eaten, and
- the amount of water the pet has consumed.
Proper monitoring of diabetes in dogs and cats is necessary to properly regulate the dosage of insulin and schedule of insulin administration. Blood glucose curves are a commonly performed test to help monitor diabetic pets and can be easily be done by pet owners at home.
Sources:
Diabetes Mellitus in Cats, Jacquie Rand & Rhett Marshall, Veterinary Clinics of North America Small Animal Practitioner, January, 2005, Pg. 211-224.
Home monitoring of the diabetic cat, Claudia Reusch et al. Journal of Feline Medicine and Surgery April, 2006, Pg. 119-127.
Monitoring Diabetic Dogs, Part 1: Blood Glucose Curves, Keven P. Gulikers, William E. Monroe Veterinary Medicine December 2003;98(12):1025-1031.
Home Monitoring of Blood Glucose Concentration in Diabetic Dogs, C. B. Chastain, David Panciera, Small Animal Clinical Endocrinology 2004 May-Aug, Pg.9.
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