Diabetes mellitis is common in middle-aged to older cats (especially overweight cats) and middle-aged dogs. The disease occurs when the pancreas doesn’t produce enough insulin, which then causes blood sugar to rise. We diagnose diabetes when we see a combination of high blood sugar and glucose in the urine. Some pets (especially cats) can have high blood sugar from stress alone. In these cases, we perform a fructosamine test, which measures the average blood glucose level over the previous couple of weeks. This helps us differentiate between a one-time elevated glucose level due to stress and persistent elevations of glucose seen in true diabetics.

Symptoms of Diabetes

Early on, most diabetics usually don’t feel sick, however pet owners usually notice excessive water drinking and urination, weight loss (despite good appetite), and weakness. If the diabetic pet goes undiagnosed for a prolonged period, more severe signs of disease (e.g. Ketoacidosis) ensue. These pets are presented usually in medical emergency. Therefore, early diagnosis and treatment are important.  Treating with insulin is almost always necessary and the only way to stabilize symptoms.


Other Signs of Diabetes include:

  • Cataracts:  In dogs, high blood sugar levels cause rapid cataract formation.  This is rarely seen in cats.  Cataracts can form so quickly that a cloudy eye and vision loss are the first signs noticed at home.  Cataract surgery to correct this problem will improve vision and quality of life in many pets.
  • Infections:  Diabetics are at increased risk for infection, especially urinary tract infections. In many cases, diabetics don’t show signs of infection (accidents in the house, blood in the urine).  A urine culture should be performed in new or unregulated diabetics.


Treatment of Diabetes


  • Insulin

Most diabetic pets are dependent on insulin shots to control their blood sugar.  There are many types of insulin on the market including some produced specifically for pets. Finding the right type of insulin and the proper dose requires time and some trial and error. For many owners, giving insulin injections is the most intimidating part of caring for a diabetic pet.  Once you are shown how to give  insulin injections, you’ll be surprised at how easy it is and how most pets don’t mind their shots. However, diabetic pets need routine follow-up examinations to determine if their insulin needs have changed.

  • Diet

Diets that have a low glycemic index (diets that don’t cause spikes in blood sugar) are important in diabetics.  Treats that aren’t sweet are allowed, but it is important to be consistent both in diet and feeding time.


Common Complications of Diabetes Mellitus 


  • Pancreatitis

Diabetics are at increased risk of pancreatitis (inflammation of the pancreas). Common signs of this include vomiting, abdominal pain, poor appetite, and lethargy.

  • Diabetic Ketoacidosis (DKA)

In uncontrolled diabetes, fat stores are broken down resulting in a buildup of ketones (an acid) in the blood and urine, eventually making the animal feel sick. DKA is a serious condition that occurs most commonly in new diabetics, in diabetics who haven’t received their insulin, or those who have developed other diseases (pancreatitis, urinary tract infections, etc.). Signs of DKA include loss of appetite, vomiting, lethargy, and signs of uncontrolled diabetes (increased thirst and urination).

  • Hypoglycemia

Hypoglycemia can be a more serious problem than high blood sugar. This can occur with overdoses of insulin (e.g. if a second dose of insulin is mistakenly given or if too much is drawn up) or if an animal’s insulin needs have changes. If your pet appears wobbly, disoriented, or spacey, it may be due to low blood sugar.


If You Suspect Low Blood Sugar in Your Pet:

  • Try feeding a small meal. Do not attempt to feed your pet if they are unconscious or weak enough that they may not be able to swallow normally
  • If they are not willing or are unable to eat, rub some corn syrup or honey on their gums
  • For all cases of hypoglycemia, please seek medical attention for your pet as soon as possible