Diabetes mellitus – which means “sweet urine” in Latin – is one of the most common endocrine diseases we see in pets. “Endocrine” means having to do with hormones; those chemicals produced by the body that control so many of its vital processes.
Most people know a person with diabetes, because unfortunately it’s become one of the most common diseases in people as well. Most humans get what has been named Type 2 or adult-onset diabetes. Dogs, it turns out, are typically the victims of Type 1 diabetes, which is also referred to as Juvenile Diabetes in people.
Type 1 diabetes occurs when there’s not enough of the hormone insulin, which is produced by the pancreas, to get glucose, which typically enters the bloodstream from the foods that a dog eats, into the cells. Without glucose, cells can’t function properly, and a host of complications ensue.
Diabetes can be treated, but first you have to recognize the signs, and then get your dog diagnosed. Here are some common warning signs that your dog may have diabetes.
Excessive urination
Because there is not enough insulin in the blood to take glucose in to the cells, the amount of glucose in the blood skyrockets. You’ve no doubt heard people talking about having “high blood sugar” – well, it happens to diabetic dogs, too.
But you may not have realized that this leads to something that you can observe in your pet – an increase in the frequency and amount of urination. Because of something called osmosis, the big glucose molecules in the blood pull lots and lots of water with them. This increase in water causes an increase in the amount of urine produced, and therefore you’ll see your dog urinating large volumes, and/or asking to be let out more frequently.
Excessive thirst
Because of the increase in glucose in the blood causing more urine production, the dog gets thirstier and thirstier, in an effort to replace the amount of water they are losing through urination. Ultimately they can’t replace with drinking what they’re losing through urination. This typically leads to dehydration, or sub-normal fluid levels in the body.
Doctors call this cycle of excessive urination and excessive thirst “polyuria and polydipsia”, or PU/PD. It can be the sign of many disorders, so if you see this in your pet, don’t assume it’s diabetes.
Urinating in the house
We said in earlier in the article that a dog with diabetes has a lot of glucose in his urine, because the body can’t get it into the cells where it’s needed. This creates an excellent environment for bacteria to grow and thrive – they do, after all, need food just like every other living organism, and it turns out that sugar-loaded urine is like a delicious crème brulee to them.
So, dogs with diabetes frequently have bladder infections, and owners will sometimes notice that a previously house-broken dog will urinate in the house. This is because the infection causes inflammation and pain along the urinary tract, and makes it difficult for even a well-trained dog to “hold-it” like they normally do. Sometimes an owner will notice blood in the urine, which is another sign of a urinary tract infection.
Ravenous appetite +/- weight loss
We all love it when our dogs have a good appetite. But because of their disease, diabetic dogs cannot utilize the energy in the food they eat – remember, without insulin glucose can’t get into the cells to be utilized. So these patients will often have a robust if not ravenous appetite, yet they’ll lose weight.
This is a good time to mention that one of the reasons you should see your veterinarian every year for an exam – and every six months if your dog is over seven years old – is to get him weighed. Especially in large dogs, it’s sometimes difficult to notice weight loss.
Changes in vision
One of the most common complications of diabetes in dogs is cataract development. A cataract is a thickening of the lens of the eye. Once again, excessive glucose in the blood is the culprit, drawing water into the lens of the eyes, leading to a clouding of the lens and eventually a cataract. Even dogs that are being treated for diabetes will typically develop cataracts.
If your dog develops cataracts, you might notice that the eyes (or one eye) look white, and you may see your dog running in to furniture or walls. In the early stages the changes might be subtle, such as difficulty seeing only at night or in low-light conditions.
A benign (non-harmful) condition called lenticular sclerosis is often mistaken for cataracts by owners. A veterinarian can very easily distinguish between the two conditions by performing an eye exam using a tool called an ophthalmoscope.