Diabetes Mellitus in Cats and Dogs

What is Diabetes Mellitus?

Diabetes Mellitus (DM) is a condition in which there is a deficiency of, or insensitivity to, insulin.  The pancreas produce insulin which is normally responsible for controlling appropriate levels of glucose (sugar) in the blood.  Insulin works to move glucose into the body's cells where it can be utilized for energy.  When insulin is lacking, the blood sugar rises in the blood.  Pets who are overweight are at the greatest risk of developing DM.  Cats and dogs typically present to their veterinarian with excessive drinking and urination, an increased appetite in the face of weight loss, and sticky sweet-smelling urine.  Diabetes Mellitus can be diagnosed through blood work and urinalysis.

There are two types of DM:  Type 1 and Type 2.  Type 1 occurs when the pancreas cannot produce insulin.  This is the most common form of DM in dogs.  Type 2 diabetes occurs when the pancreas only produce a small amount of insulin or the cells cannot utilize the insulin that is present.  This is the most common form of DM in cats.  All pets will need to start a treatment protocol to manage the disease, regardless of the type.

How is it treated?

The most common treatment for Diabetes Mellitus (DM) is insulin administration.  This may require a once or twice daily injection under the skin.  Glucose levels should be closely monitored, especially early in treatment to determine the proper dose of insulin.  Too much insulin will lead to hypoglycemia (low glucose) and not enough insulin will keep glucose levels higher than ideal.  Both low and high blood glucose result in particular symptoms that you should watch for.  Low blood glucose can be life threatening.

There are also oral medications that work in some cats helping to stimulate insulin production by the pancreas as well as improve the cell's insulin receptiveness.  Diet is important and can help regulate glucose levels.  High protein diets will help to maintain proper body weight and keep blood glucose levels lower.

 What is the prognosis for Diabetes Mellitus?

Once glucose levels are regulated and remain stabilized your pet can live many happy, quality years.  If regulation becomes difficult due to resistance to insulin, concurrent disease, etc., this disease will ultimately shorten your pet's life.  If glucose levels remain high, your pet may develop a condition called ketoacidosis in an effort to produce the energy needed to survive.  If left untreated ketoacidosis is fatal.  A personalized treatment plan is important to slow the progression of diabetes.  Your veterinarian will provide the best treatment protocol for your pet.

What symptoms can present as the disease progresses?


  • Increased drinking and urination
  • Increased appetite
  • Weight loss
  • Sticky, sweet-smelling urine
  • Bladder infections
  • Dental problems
  • Lethargy
  • Persistent early stages
  • Severe weight loss
  • Cataracts/blindness - Dogs
  • Organ failure
  • Dehydration
  • Neuropathies in cats
  • Unable to stand
  • If your pet exhibits any of the following symptoms immediate veterinary assistance is needed regardless of the disease.
    • Difficulty breathing
    • Prolonged seizures
    • Uncontrollable vomiting/diarrhea
    • Sudden collapse
    • Profuse bleeding - internal or external
    • Crying/whining from pain