Diabetes Mellitus in Dogs

What is diabetes mellitus?

Diabetes mellitus is a disease in which the body cannot control the level of sugar (glucose) in the blood. In dogs it is almost always caused by the pancreas failing to make enough insulin, the hormone that moves glucose from the bloodstream into the cells that need it. Without insulin, glucose builds up in the blood and spills into the urine while the body's cells starve. This is similar to type 1 diabetes in people, and it is why nearly all diabetic dogs need insulin injections for life.

Diabetes is most common in middle-aged and older dogs. Unspayed females, overweight dogs, dogs with a history of pancreatitis, and certain breeds such as Miniature Schnauzers, Poodles, Dachshunds, Beagles, and Samoyeds are at higher risk.

What are the signs?

• Drinking far more water than usual
• Urinating more often and in larger amounts, sometimes with accidents indoors
• A big appetite paired with weight loss
• Cloudy eyes from cataracts, which develop quickly in diabetic dogs
• A dull coat, lethargy, or recurring urinary tract infections

A dog that stops eating, vomits, becomes weak, or breathes with a sweet or chemical smell may be in diabetic ketoacidosis, a life-threatening complication that needs emergency care.

How is diabetes diagnosed?

A persistently high blood glucose together with glucose in the urine confirms the diagnosis. We also run a full blood panel and urinalysis, and often a urine culture, because infections and other diseases such as Cushing's disease or pancreatitis are common alongside diabetes and can make it harder to control.

How is it treated?

Treatment has three parts that work together:

• Insulin, given by a small injection under the skin, usually twice a day about twelve hours apart, right after meals. We teach you how to draw up and give the injection; most owners find it far easier than they expected, and most dogs barely notice.
• Diet, with consistent meals of the same food at the same times each day, often a high-fiber diet that slows the absorption of sugar.
• A steady routine, because changes in feeding, exercise, or timing change how much insulin is needed.

Spaying is recommended for intact females, since the hormones of the heat cycle interfere with insulin.

How is the dose adjusted?

The right dose is worked out over the first several weeks using blood glucose curves, where glucose is measured every couple of hours through a day, or with a continuous glucose monitor worn on the skin. Never change the dose on your own. Once the dog is stable, rechecks every few months and an eye on water intake, appetite, and weight at home keep things on track.

What is hypoglycemia and what do I do about it?

Too much insulin, a missed meal, or unusual exercise can push blood sugar too low. Signs are weakness, wobbliness, glassy eyes, trembling, disorientation, and in severe cases seizures or collapse. If you see these, rub corn syrup or honey on the gums, offer food if the dog can swallow, and call us immediately. If your dog does not eat a meal, do not give the full insulin dose; call for advice.

What is the long-term outlook?

With daily insulin and a consistent routine, most diabetic dogs live happy, normal lives for years. Cataracts are very common and can be surgically removed to restore sight. The commitment is real, but it quickly becomes part of the household rhythm.

See also: Diabetes Mellitus in Cats