Canine Diabetes: Causes, Symptoms, Diagnosis & Treatment

Canine Diabetes Mellitus

Diabetes is one of the most common health conditions found in middle-aged dogs (and cats). It is a disease of the pancreas (not to be confused with pancreatitis). The pancreas has two groups of cells: one that produces enzymes to help your pup properly digest his food, and the other produces a hormone called insulin, which regulates the amount of glucose (sugar) in your dog’s bloodstream and delivers it to the necessary tissues. 

In simple terms, canine diabetes mellitus (CDM) occurs when the pancreas fails to regulate blood sugar.

Generally speaking, diabetes is a lifelong condition, and controlling it will require a great deal of time, effort (and money) from you, the pet parent. Fortunately, many dogs with diabetes are able to continue leading long and happy lives as long as the condition is properly managed.

Today we’ll talk about everything you need to know about canine diabetes, including:

What is canine diabetes mellitus?

In veterinary medicine, diabetes refers to two unrelated conditions: diabetes mellitus (sugar diabetes) and diabetes insipidus (water diabetes). Since diabetes mellitus is more common in dogs, that’s what we’ll talk about today.

You may associate the term “diabetes” with “blood sugar,” and you’re right to do so in this case. Blood sugar in the body is called glucose, and it carries important nutrients that your dog needs to absorb into his cells. But that can’t happen without the presence of insulin, a hormone produced by the pancreas as part of the body’s natural blood sugar regulation. 

Is insulin the same as sugar?

No. The sugar in the bloodstream is called glucose. Insulin is a hormone that tells the body’s cells to absorb glucose. When there isn’t enough insulin being produced—or when the body doesn’t properly respond to the insulin— your dog’s cells aren’t able to absorb the glucose and access all the nutrients it carries. Instead, the glucose builds up in the blood, which can cause hyperglycemia (we’ll talk more about that another day). 

How many types of diabetes are there?

There are three types of diabetes mellitus:

Type I (most common in dogs): AKA insulin-dependent diabetes mellitus, type I results from the destruction of the insulin-producing beta cells. Dogs with type I diabetes need insulin injections to stabilize blood sugar levels.

Type II (most common in cats and older obese dogs): AKA non-insulin-dependent diabetes mellitus, type II results from an insufficient production of insulin, a delayed response in secreting insulin, or your dog’s tissues are insulin resistant. Unlike humans, dogs do not respond well to insulin-producing medications. Instead, they typically need to be given some insulin.

Type III: the third type of diabetes results from insulin resistance caused by hormones, either from pregnancy or hormone-secreting tumors. 

What causes diabetes in dogs?

Type I diabetes generally affects dogs over the age of 8. While any breed of dog can develop any type of diabetes, there are a handful of smaller breeds that seem to be more susceptible to becoming diabetic, including:

  • Miniature Poodles
  • Dachshunds
  • Schnauzers
  • Cairn Terriers
  • Beagles

A recent study found that feeding a high-fat diet, which can cause excess weight gain, is one of the main contributing factors to canine diabetes.

Another study found that extensive pancreatic damage (generally caused by chronic pancreatitis) causes roughly 30% of canine diabetes cases. 

What are the symptoms of diabetes in dogs?

There are four primary symptoms of diabetes in dogs:

  1. Increased urination: your dog’s body will attempt to eliminate excess glucose by excreting it in the urine. Glucose attracts water, which increases the amount of urine produced.
  2. Increased thirst: to avoid becoming dehydrated, your dog will naturally drink more water.
  3. Weight loss: When your dog’s cells aren’t getting the energy they need from glucose, his body becomes “starved” and starts using previously stored fat and protein for energy. This causes weight loss.
  4. Increased appetite:The apparent starvation also increases your dog’s appetite, causing him to eat more, all the while continuing to lose weight.

How is canine diabetes diagnosed?

Diagnosing canine diabetes is relatively straightforward. The three main indicators of diabetes in dogs are:

  • Symptoms (listed above)
  • High levels of glucose in the blood
  • Glucose in the urine

Your vet should perform an overall health examination, which includes talking to you, the pet parent, about changes in appetite, weight, thirst and urination frequency. They’ll also run some blood tests and perform a urinalysis. 

How do I treat my dog’s diabetes?

In addition to eating a balanced, healthy diet, most dogs with diabetes will need daily insulin injections

When your pup is first diagnosed with diabetes (or if he is in an immediate crisis), he’ll be hospitalized for a few days to have his blood sugar stabilized and his insulin regulated. If you have a female dog, your vet may also recommend having her spayed. 

Once your vet is comfortable that your dog is responding well to the insulin injections, he’ll be sent home and you’ll begin to administer the injections yourself. You’ll want to keep in close contact with your vet during the initial phase of insulin therapy to be sure everything is going as planned. 

You’ll also want to pick up a glucose monitor (called a glucometer), which you can use at home to track your dog’s glucose levels. It can take up to a month or more to properly regulate your dog’s insulin—some dogs are easy to regulate, and some aren’t. 

Consistency is key:

  • Feed your dog the same food (high fiber is recommended) in the same amounts at the same time every day
  • Administer his insulin injections (usually twice a day) at the same times every day
  • Make sure your dog is getting daily exercise 

Canine diabetes mellitus warnings

Generally speaking, diabetes is a controllable disease. However, there are some serious issues to be aware of:

  • Diabetic dogs are less resistant to bacterial and fungal infections, and can develop chronic or recurrent cystitis, prostatitis, bronchopneumonia, and dermatitis
  • Hepatomegaly (an abnormally enlarged liver) due to lipid accumulation is common in dogs with diabetes.
  • Dogs with diabetes may also form cataracts, whereby the lens of the eye will get cloudy due to changes in the water balance or to the proteins within the lens.
  • Diabetic ketoacidosis is a form of decompensated diabetes mellitus. When glucose and ketoacids accumulate in the blood, potentially life-threatening metabolic disturbances occur.
  • Other issues that can arise include hind leg weakness caused by low blood potassium (aka hypokalemia), high blood pressure (aka hypertension), or lower urinary tract infections (UTIs).

Canine diabetes prognosis

Once canine diabetes is properly controlled, your dog's prognosis is very good … as long as you keep up with the proper treatment and consistently monitor his blood sugar levels. In fact, most dogs will go on to live a happy life with few symptoms.