Continuous glucose monitoring in diabetic dogs and cats

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Continuous glucose monitoring in diabetic dogs and cats

Continuous glucose monitoring in diabetic

dogs and cats


Diabetic Monitoring

Usually performed in diabetic dogs and cats by:

History

Clinical examination findings

Urine glucose monitoring at home

Serial blood glucose curves

- in hospital or at home

Serum fructosamine

Slide 2


Blood Glucose Curve

Measurement every 1-2 hours

Advantages

- Duration of insulin effects

- Degree of blood glucose fluctuation

- Nadir

Disadvantages

- Stress hyperglycaemia in cats

- Inappetence and change in activity

- Variability in insulin administration

- Day to day variability

- Time of curve (generally during day only)

Slide 3


Serum Fructosamine

Fructosamine – glycosylated serum proteins

Advantages

- Proportional to blood glucose over life span of protein: (1-2 weeks)

Disadvantages

- Affected by conditions that alter serum fructosamine

- Does not provide information on

‣ nadir

‣ acute change in glucose concentrations

Slide 4


Continuous Glucose Monitoring

(CGM)

228 data points per 24 hours

We use the Guardian Real-Time CGM system

- Disposable sensor

- Transmitter

- Pagerised monitor

Oxidation of hydrogen peroxide from glucose and oxygen

in interstitial fluid generates a current that is converted to

glucose concentration

Slide 5


Placement and Calibration

The device is a very small needle attached to a sensor that

we generally place over the side of the thorax. The

transmitted is then attached and bandaged in place, with the

monitor kept close by (generally front of cage).

There is then a period of initialisation followed by calibration

every 6-8 hours.

The BG results can then be downloaded for up to 72

continuous hours.

Slide 6


Literature Review

Evaluation of a continuous glucose monitoring system in cats

with diabetes mellitus (Ristic et al. 2005)

-14 diabetic cats

-MiniMed CGM 72 h

-Blood glucose measured q4 hours

-Spearman Rank correlation coefficient - interstitial fluid

glucose concentrations to blood glucose r = 0.862

Slide 7


Literature Review

Evaluation of a Novel Real-Time Continuous Glucose-

Monitoring System for Use in Cats (Moretti et al. 2010)

-39 cats (32 diabetes mellitus, 2 insulinoma, 5 healthy)

-10-15 paired glucose measurements from each cat = 448

data pairs

-CGM was 100%, 96.1% and 91% accurate at high, normal

and low blood glucose measurements

Slide 8


Literature Review

Comparison of a Continuous Glucose Monitoring System with a

Portable Blood Glucose Meter to Determine Insulin Dose in Cats

with Diabetes Mellitus (Dietiker-Moretti et al. 2011)

-14 cats with diabetes mellitus (glargine insulin)

-Concurrent blood glucose measurements over 8-10 h

-21 paired profiles generated from 13 cats

-3 small animal boarded clinicians assessed independently

- No significant overall difference between the insulin

doses deduced from the 2 methods

-Limitations: small numbers, short time frame, repeated

handling and phlebotomy (stress)

Slide 9


Nocturnal Hypoglycaemia

and the Somogyi effect

Nocturnal hypoglycaemia recognised in human

medicine, but we suspect in veterinary patients

- Would be missed with day-time glucose curve

Somogyi effect - High morning fasting

hyperglycaemia following nocturnal

hypoglycaemia

- due to the release of counter-regulatory hormones in response to nocturnal

insulin induced hypoglycemia

- the existence of the Somogyi effect remains a matter of debate

- studies in human medicine support and oppose the phenomenon

Slide 10

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