Diabetes Mellitus

Diabetes mellitus is a hormonal disease that occurs in about 1 out of every 400 cats. It is characterised by elevated blood glucose (blood sugar) levels. If untreated, it can lead to life-threatening metabolic disturbances.  Diabetes in cats is most similar to type II or adult onset diabetes in humans.

The hormone insulin is produced in the pancreas and is responsible for allowing glucose to be transported into cells to provide energy.  If there is resistance or reduction in the amount of insulin produced, then the cat becomes diabetic.

Cats who are MOST at risk:
  • Over eight years old
  • Male
  • Burmese breed
  • Overweight

Signs and Symptoms

Clinical signs of diabetes include:
  • Excessive drinking
  • Excessive urinating
  • Increased appetite
  • Problems with mobility e.g walking or jumping (this is caused by neuropathy - poor nervous control to the cat’s hind legs)


Blood and urine tests are used to demonstrate high blood glucose and the presence of glucose in the urine. Occasionally, a test for fructosamine is required to distinguish between cats which are stressed and those that are truly diabetic.


Diabetes is a very treatable disease, but requires long term commitment.

Treatment options include:
  • Treating underlying disease (if there is one)
  • Insulin therapy (the preferred method, and the one that provides the best control of blood sugar)
  • Dietary management (there have been significant advances in dietary treatment of feline diabetes recently)

After your cat has been diagnosed, the next step is to determine the correct type and dose of insulin for them; this varies for each cat. Your cat will spend several days in the hospital while blood glucose is measured every few hours to determine the correct dose.

Insulin Instructions

  • Must be stored in the refrigerator
  • IF your cat is on a crystalline insulin it must be gently mixed by rolling for 30 seconds prior to each use
  • Glargine (Lantus) insulin does not need to be mixed
  • New syringe should ideally be used for each injection
  • Injections can be given under the skin anywhere on the body but the "scruff" is often easiest and less painful

Your cat MUST be monitored closely during insulin therapy.

Monitoring the effect of insulin dosing including:
  • Placing a continuous glucose monitor which lasts for 2 weeks
  • Ear vein sampling OR
  • Regular blood glucose curves at the clinic

Insulin dose can be changed according to the Home Glucose Monitoring guidelines without consulting your veterinarian but initially most clients phone us to discuss their decisions and we are happy to provide this service.


If your cat gets TOO MUCH insulin it can cause blood glucose levels to become dangerously low, become weak, lethargic or unsteady on their feet and in severe cases could go blind, go into a coma or die.

If your cat accidentally gets too much insulin or if it shows any of these signs, take her to the vet immediately. You might try rubbing honey or glucose syrup on her gums as an emergency treatment.


Approximately 50% of cats diagnosed with diabetes and treated appropriately will go into remission and no longer require insulin injections. Early diagnosis and aggressive treatment with long-acting insulin and a low carbohydrate diet will increase the chance of your cat going into remission.


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