ISSN 2398-2950      

Diabetes mellitus: outcome and complications of treatment


Carmel Mooney

Outcome of diabetes mellitus

  • Some diabetic cats achieve remission after instituting therapy.
  • Remission in diabetic cats:
    • Occurs in many cats but the actual number is dependent on diet fed, intensity of monitoring regimen and possibly insulin type.
    • Remission is more likely:
      • In newly diagnosed (<6 months since diagnosis) diabetic cats.
      • In cats that achieve more rapid glycemic control.
      • In those with less severe hyperglycemia before treatment.
    • Remission is most likely within the first 3-4 months of therapy.
    • Approximately 25-30% of cats in remission relapse:
      • Remission becomes less likely the more relapses occur.
    • Cats in remission have a greater survival time compared to those that remain diabetic.
      Follow the diagnostic tree for Diabetes remission in cats Diabetic remission in cats.
  • Many diabetic cats are stable on treatment. Such cats:
    • Exhibit adequate resolution of clinical signs such as polyuria/polydipsia.
    • Maintain a good appetite and optimal body condition.
    • Have a reasonable quality of life as judged by their owners.
    • Show minimal complications such as ketosis, infections and other diabetic complications.
    • Have reasonable fructsamine Blood biochemistry: fructosamine concentrations.
    • Receive conventional insulin doses between 1 and 5 IU/cat/injection Diabetes: management regimens.
    • Have acceptable blood glucose concentrations Blood biochemistry: glucose although not necessarily euglycemia during the inter-injection intervals.
    • Have a reasonable prognosis and life expectancy, often succumbing to diseases other than diabetes mellitus.
  • A proportion of diabetic cats require investigation because of persistence or recurrence of diabetes mellitus despite what is considered adequate treatment:
  • Unstable diabetic cats:
    • Exhibit poor control of clinical signs:
      • From the initiation of treatment.
      • Or after achieving stability for a variable period of time.
    • Are at high risk of diabetic complications such as ketoacidosis Diabetic ketoacidosis and worsening neuropathies.
    • Have inappropriately high blood glucose concentrations during the inter-injection interval but not always at the nadir point.
    • Have high or rising fructosamine concentrations.
    • Usually receive increasing doses of insulin to control clinical signs, often greater than 5 IU/cat/injection with associated risks of developing hypoglycemia Hypoglycemia.

The potential causes of diabetic instability can be broadly divided into 3 categories

Management issues

  • Problems with insulin administration:
    • Incorrect preparation of dose.
    • Inappropriate syringe type for insulin strength.
    • Injection into hair.
    • Injection into fat.
    • Injection into single fibrosed site.
    • Wide dose adjustments.
  • Timing of insulin injections:
    • Variable timing.
    • Frequently missed injections.
  • Feeding:
    • Variable diet.
    • Inappropriate timing.
    • Incorrect composition regarding protein and carbohydrate.
  • Handling of insulin:
    • Dilution.
    • Improper storage.
    • Inactivation due to vigorous shaking.
    • Use of out-of-date insulin.

Insulin problems

  • Inadequate dose.
  • Short duration of activity.
  • Prolonged duration of activity.
  • Excessive dose resulting in Somogyi overswing.

Insulin resistance

Follow the diagnostic trees for Lack of Diabetic Control in Cats Lack of Diabetic Control in Cats and Persistent Hyperglycemia in Diabetic Dogs and Cats Persistent Hyperglycemia in Diabetic Dogs and Cats.

Print off the owner factsheet on Diabetes mellitus Diabetes mellitus  and give to your client.

Investigation of unstable diabetes mellitus

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Other complications

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Further Reading


Refereed papers

  • Recent references from PubMed and VetMedResource.
  • Sparkes A H, Cannon M, Church D et al (2015) ISFM consensus guidelines on the practical management of diabetes mellitus in cats. J Feline Med Surg 17 (3), 235-250 PubMed.
  • Gostelow R, Forcada Y, Graves T et al (2014) Systematic review of feline diabetic remission: separating fact form opinion. Vet J 202, 208-221 SemanticScholar.
  • Callegari C, Mercuriali E, Hafner M et al (2013) Survival time and prognostic factors in cats with newly diagnosed diabetes mellitus: 114 cases (2000-2009). JAVMA 243 (1), 91-95 PubMed
  • Niessen S J (2010) Feline acromegaly: an essential diagnosis for the difficult diabetic. J Feline Med Surg 12 (1), 15-23 PubMed.
  • Williams D L & Heath M F (2006) Prevalence of feline cataract: results of a cross-sectional study of 2000 normal animals, 50 cats with diabetes and one hundred cats following dehydrational crises. Vet Ophthalmol (5), 341-349 PubMed.
  • Thoresen S I, Bjerkås E, Aleksandersen M et al (2002) Diabetes mellitus and bilateral cataracts in a kitten. J Feline Med Surg (2), 115-122 PubMed.
  • Whitley N T, Drobatz K J & Panciera D L (1997) Insulin overdose in dogs and cats - 28 cases. (1986-1993). JAVMA 211 (3), 326-330 PubMed.
  • Hatchell D L, Toth C A, Barden C A et al (1995) Diabetic retinopathy in a cat. Exp Eye Res 60 (5), 591-593 PubMed.
  • McMillan F D & Feldman E C (1986) Rebound hypoglycaemia following overdosage of insulin in cats with diabetes mellitus. JAVMA 188 (12), 1426-1431 PubMed.

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