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The feline diabetic–friend or foe?(Proceedings)

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Nov 01, 2010

Is the feline diabetic patient every veterinarian's nightmare? Since diabetes mellitus is one of the most common endocrinopathies in cats, it is likely you will face this disease many times in your veterinary career. The focus of this presentation will be to discuss the problems you may encounter with your feline diabetic foes using case studies to illustrate how these feline diabetics can be your friends.

Monitoring:

      Clinical signs – water consumption, urination habits, appetite, activity, weight gain/loss
      Blood glucose curves – useful to find nadir (low point), identify Somogyi effect but overall frustrating and difficult to interpret. Use sparingly.Some clients are willing to follow blood glucose readings at home, which has its advantages and disadvantages. The personal blood glucometers are sufficiently accurate, though some meters are more accurate than others. I rely on my in-house readings to adjust insulin doses.
      Fructosamine levels – Reliable; useful for all cats, especially fractious ones...! These levels inconjunction with spot blood glucose readings have replaced blood glucose curves in my hands.
      Urine glucose monitoring – urine glucose test squares (Glucotest Feline Urinary Glucose Detection System; Ralston Purina, St. Louis, MO) can be mixed in cat litter. Useful for non-insulin dependent patients to determine if glucosuria has recurred; persistent glucosuriasuggests inadequate control and the need for reevaluation. Do not have owners adjustinsulin levels based on urine glucose measurements.

Suspect insulin resistance when:

      Dose of insulin is 6-8U (cat) q.12h and all BG levels >300 mg/dl
      Dose of insulin is >2.2U/kg to maintain BG < 300 mg/dl

Insulin resistance problems: The hunt for the problem(s) begins...

Insulin administration problems are the most common problems identified in poorly regulated diabetics. Over 80% of poorly regulated diabetic patients are due to administration issues...!

     • Vary location of injection sites.
     • Shave injection sites. (Eliminate the "fur" injection problem.)
     • Spend time training/testing clients on insulin administration. Make sure all the familymembers who will be giving the injections are trained.
     • Have the client obtain a new bottle of insulin every 4 weeks for all insulin types except Lantus.Lantus should remain potent for up to 4-6 months. If diabetic control with Lantus is poor, have the Client change to a new bottle every 2-3 months.
     • When poor diabetic control is present, review insulin administration techniques with the client and everyone giving the insulin injections. Don't forget to include the petsitter.

Every diabetic cat, especially those that are difficult to regulate, should have a full physical examination, complete diagnostic evaluation (CBC, biochemistry profile, serum T4, urinalysis), blood pressure measurement, and fructosamine level.

Imaging studies (radiographs, ultrasound) and more extensive testing may be needed to rule out concurrent diseases.

Don't forget to check for urine ketones.

Ketones are the end-product of rapid or excessive fatty-acid breakdown.

     • Acetoacetic acid
     • Acetone
     • Beta-hydroxybutyrate

Glomeruli freely filter ketones and the tubules then resorb them completely. If the tubular resorptive capacity is saturated, then the ketones are incompletely resorbed, resulting in ketonuria. Ketonuria occurs quickly in younger animals and is more easily detected than ketonemia. Ketonuria does not signify renal disease, but rather excessive lipid or defective carbohydrate metabolism. Ketones will be present in the urine when the ketones in the blood go above a certain level.

The ketone present in the largest amount, beta-hydroxybutyrate, does not register on the urine dipstick. Dipstick tests are semiquantitative and only detect acetone and acetoacetic acid. Reagent strips contain nitroprusside that does not react with beta-hydroxybutyric acid. However, you can perform a simple chemistry maneuver to determine if any ketones are present. One drop of urine plus one drop of hydrogen peroxide will convert beta-hydroxybutyrate to acetoacetic acid which does register on the urine dipstick.