Diabetes mellitus (Proceedings) - Veterinary Healthcare


Diabetes mellitus (Proceedings)


When multiple daily urine glucose determinations are performed, the pattern of glucosuria may provide useful information. Persistent glucosuria greater than 1000 mg/dl throughout the day, is clear evidence that the insulin dose needs to be increased whereas variation in urine glucose concentration from negative to 1000 mg/dl demands some analysis. Urine formed during the anticipated waning period of action after insulin administration, for example, may have urine concentration of 1000 mg/dl (1%) while urine formed earlier during peak insulin action may be negative. On the other hand, if urine glucose at peak insulin action is 500 mg/dl (1/2%) and 1000 mg/dl near the end of insulin activity, increased insulin dose is needed whereas in the first example, it is more likely that the duration of insulin action is slightly less than anticipated.

Urine Ketone Estimating – When the concentration of urine ketone bodies in glomerular filtrate exceeds tubular resorptive capacity, acetoacetate can be detected by KetoDiastix urine reagent pad analysis. Urine ketone bodies are often present in urine of diabetic dogs when initially treated with insulin at home. Resolution of ketonuria is usually accomplished in 3 or 4 days. Thereafter, ketones are seldom detected in urine unless the insulin dose is chronically less than required and diabetes is poorly controlled. An exception to this generalization is the occasional diabetic dog that is prone to form ketones in spite of adequate control of diabetes.

Blood Glucose Curves – The determination of blood glucose concentration at approximately 2 hour intervals for 12 to 24 hours has been termed a blood glucose curve. The blood sampling and determinations are usually done in the veterinarian's office. The results are used to gain a more complete understanding of the effects of each insulin administration and the overall control of diabetes. It has been documented, however, that the results are not as reliable as previously thought. Lack of reliability and relevance of the procedure is thought to be related to factors such as apprehension and excitement. Although validity of glucose curves can be improved by performing them 3 days in succession, overall patient care is disrupted and compromised. For these reasons, blood glucose curves are not routinely done on every diabetic but are reserved for problem cases. In general, the shape of the curve obtained is of greater validity than are the individual determinations.

Spot Blood Glucose Determinations – Individual blood glucose determinations have also been used to assess diabetes control but limitations must be kept in mind. Blood glucose may not be representative of the concentrations an hour before or after and the blood glucose nadir cannot be predicted. A previously determined blood glucose curve may be helpful in predicting nadir because the shape of the curve does tend to be reliable although the actual individual determinations are subject to lack of reliability.

Caregiver Home Blood Glucose Monitoring – It is increasingly common for caregivers to monitor blood glucose using commercially available glucometers used by human diabetics. Selection of the site for procuring the necessary drop of blood is highly individualized and dependent on the response of the dog and the preference of the caregiver. Sites include ear tips, footpads and elbow calluses.

Glucometers – Commercially available glucometers designed for home monitoring by human diabetics are readily attainable at a reasonable price. The instruments are quite accurate when used with dog or cat blood except at the lower range of blood glucose concentration (< 80 mg/dl). In this range, human glucometers tend to underestimate glucose concentration of cat and dog blood because of species difference in erythrocyte size. In the course of home monitoring diabetes, it is not common for the home caregiver to be dealing with hypoglycemia. Regardless, the glucometers tend to under estimate rather than over estimate blood glucose. Glucometer systems marketed for dogs and cats include AlphaTRAK™ by Abbott Laboratories and GlucoPet® and GlucoVet® by Animal Diabetes. Dog and cat glucometer systems are more expensive than human products.

Continuous Glucose Monitors – Glucose monitoring systems that provide interstitial fluid glucose determinations at 5-minute intervals for 3 days are also available. Systems such as Medronics' Continuous Glucose Monitoring system have been used in cats and dogs. A small, light-weight (less than 1 ounce) subcutaneous sensor with transmitter sends glucose readings at 5-minute intervals to a remote receiver that stores the data until retrieved for analysis. Calibrating glucose determinations from an external source must be performed and entered into the system every 12 hours. Although some study time must be devoted to gain familiarity with the system, remarkable data are generated for understanding the diabetic's response to insulin.

Fructosamine-An assessment of glucose control over the preceding weeks or months is possible by determining the degree to which body proteins have become non-enzymatically combined with glucose. Fructosamine is the established term foserum or plasma proteins that are glycated or glycosylated (non-enzymatically combined with glucose). Fructosamine determinations are useful for assessing glycemic control during the preceding 1-3 weeks and are commonly used by veterinarians to assess diabetes control in dogs and cats. Physicians more commonly use glycated hemglobin (hemglobin A1c) to assess glycemic control over the preceding 3-4 months.


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