Causes Of Diabetes Disregulation In Dogs And Cats

Why does a perfectly-well-regulated diabetic pet suddenly become disregulated?

Diabetic pets, once regulated, are usually easy to maintain unless complicating factors come along.

The possible reasons are many, and we will cover some of them today.

Statistically, the single most common disregulating factor is urinary tract infection (UTI). Diabetic dogs and cats often have compromised immune systems, so their normal body defenses don’t work properly.

In addition, there is ample fuel in the diabetic pet’s urinary tract to support UTI. Normal urine should be completely glucose-free. Even the best-controlled diabetic pet has glucose in the urine at least part of the day. Under perfect conditions, bacteria entering the urinary tract would be attacked by the immune system’s protective functions and be eliminated. Combine a weakened immunity with an essential nutrient for rapid bacterial reproduction and the scenario is excellent for infection to occur.

Indeed, we know that many diabetic pets even lack the ability to mount a significant cell-mediated immune (CMI) response. From a practical standpoint, that means that not only does the urinary tract easily become infected, but tests may fail to show classic immune system responses, such as the presence of white blood cells (WBCs) on the urinalysis. Bacterial culture and sensitivity is the gold standard of urinary tract infection diagnosis.

Cushing’s Disease is another common complicating factor for canine (and much less commonly, feline) diabetics. Unfortunately, some of the breeds of dogs most likely to suffer from diabetes mellitus also are predisposed to hyperadrenocorticism. Case in point:  I recently treated Sasha, a longstanding Cushing’s patient for what seemed at first to be failure of her Cushing’s regulation. She had begun drinking more water, eating more and losing weight. A
chemistry profile and urinalysis quickly confirmed that the long duration of steroid excess, the hallmark of Cushing’s, had taken a toll on her pancreas’ ability to produce insulin.

The opposite also occurs, in which diabetic dogs develop Cushing’s Disease.

Any form of inflammation, chronic or acute, can throw a diabetic out of balance. Arthritis, which is inflammation in a joint cavity, can be a factor, especially if something causes a sudden worsening of the arthritis.

Infection anywhere in the body causes inflammation, just as it does in urinary tract infection. From pyoderma to an abscess from a bite wound, infections are more complicated in diabetics.

Certain medications can interfere with insulin regulation. Corticosteroids are the ultimate culprit, and sometimes pet owners contribute unknowingly. Use of over-the-counter (OTC) ointments containing cortisone or hydrocortisone are quickly absorbed through the skin and into the bloodstream. Likewise, steroid medications used to control skin problems, eye conditions and even steroid injections into joints and tendons can disregulate diabetics.

Just as in people, exercise is important in the management of diabetes in our pets. Changes, whether increasing or decreasing exercise, must be made gradually, and resulting alterations in appetite and water intake must be noted.

Hyperlipidemia, a condition of increased fats in the bloodstream, often causes disregulation or can even interfere with initial regulation.  Click the link above for a better understanding about hyperlipidemia and ways to help control it.

Then, there is the category of “operator error” problems:

  • using insulin beyond its expiration date
  • allowing insulin to reach room temperature (especially repeatedly) or even become overheated sitting in the sun or in a warm room such as kitchen or bathroom
  • other damage to insulin, such as dropping or shaking it
  • failure to “roll” the insulin bottle to resuspend the crystals into suspension
  • dietary changes (especially visitors feeding your pet or getting into the garbage)
  • changing the insulin dosage without a good reason, such as glucose curve or fructosamine test
  • accidentally purchasing U-40 insulin syringes when your insulin is U-100
  • failing to wear one’s glasses, which can result in incorrect dosing, as well as missing the skin with the needle

Diabetes mellitus in dogs and cats requires attention to consistency, making sure that every day is the same as the day before from diet to exercise to injection technique.

See you tomorrow, Dr. Randolph.


  1. Enjoyed the information about diabetes in dogs. I was wondering if there are any safe treats that can be given?

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