Yes, they can – and they do! Studies suggest that between one in five hundred and one in a hundred dogs will be diagnosed with sugar diabetes during their lives.
What is diabetes?
There are two forms of diabetes – diabetes insipidus (or “water diabetes”, where affected dogs cannot conserve water) and diabetes mellitus (“sugar diabetes”, which is much more common and is what this blog is about).
Diabetes mellitus occurs when a dog cannot control their own blood sugar; this leads to abnormally high blood glucose levels, which the dog’s cells cannot use properly. Eventually, this is likely to result in diabetic ketoacidosis – a life-threatening complication with is a medical emergency.
How is blood glucose controlled normally?
In a healthy dog, structures called the Islets of Langerhans in the pancreas produce a group of hormones that regulate their blood glucose (just like in people). There are three groups of cells, each producing a different hormone:
- Alpha Cells, which produce glucagon – to raise the blood sugar levels by telling the liver to release glucose into the bloodstream.
- Beta Cells, which produce insulin – to lower the blood sugar levels by telling the muscles and other tissues to absorb glucose.
- Delta Cells, which produce somatostatin that helps to prevent wild variations in blood sugar.
In the diabetic dog, it is the Beta Cells, the insulin they produce, or the body’s response to it that are in some way defective.
Do dogs get Type I or Type II diabetes?
In humans, we often talk about two different types of diabetes:
- Type I, where the Beta Cells are destroyed or prevented from working, so the body doesn’t make enough insulin.
- Type II, where the body tissues stop responding to insulin, also known as insulin resistance.
In dogs, however, we do not generally see these as two separate types. It is thought that although Type II disease may exist (obese dogs are at increased risk of diabetes), it usually has no symptoms because the dog’s pancreas just makes more and more insulin to counteract the insulin resistance. This then leads to Islet of Langerhans exhaustion, whereby the Beta Cells essentially give up and stop making insulin – resulting in diabetes that is more similar to Type I disease in humans.
Other medical conditions can have a similar effect, particularly Cushing’s Disease (which may be responsible for diabetes in up to 10% of cases), or progesterone release (e.g. during pregnancy or false pregnancy).
In addition, if the pancreas is physically damaged (for example in pancreatitis or after some types of surgery), the Islets may stop working properly, leading to diabetes.
What are the symptoms?
The usual symptoms of diabetes in dogs include:
- Increased hunger (although the blood glucose is high, the body cells cannot use it, so the dog thinks they are starving).
- Dehydration, increased urination and thirst (due to concentration of the blood and loss of glucose in the urine).
- Weight loss.
- Fruity or sweet breath (due to glucose, and ketone chemicals which are produced by the liver in diabetes).
- Lethargy and depression.
- Urinary tract and skin infections.
- Vomiting (in very severe or advanced cases).
- Cataract formation and blindness.
What are the possible complications?
If untreated, diabetes will eventually lead to even more severe diseases:
- Hyperosmotic coma, where the blood sugar level gets so high that the water is pulled out of the brain, causing seizures, vomiting, collapse, coma and death. This is very dangerous but fortunately rare.
- Diabetic ketoacidosis. In diabetes, the liver may respond by producing energy chemicals called ketones instead of glucose – these don’t need insulin to be absorbed so will keep the dog alive in the short term. However, if the levels of ketones stay too high for too long, they make the blood acidic; the dog becomes rapidly dehydrated, develops vomiting then collapses and without rapid emergency treatment will die.
How is diabetes diagnosed in dogs?
In most cases, appropriate symptoms combined with an abnormally high blood glucose level is sufficient to make the diagnosis. Although a high urine glucose level is very suspicious, there are a few other conditions that can lead to high urine glucose, so we would usually try to confirm it with a blood test.
However, blood glucose varies naturally throughout the day, even in diabetic dogs, so a diabetic dog at the low phase of their daily cycle may appear to have blood sugar in the normal range. Therefore, it is sometimes necessary to do a special blood test called a fructosamine test, which will measure the average blood sugar level over the previous month or so.
What is the treatment?
Dogs with diabetes almost invariably require insulin injections – this is something you as the owner will do at home. There are a number of different types of insulin available, and our vet will prescribe the most suitable type; they usually have to be given twice a day (but don’t worry, the needles are really tiny!).
In addition, good blood sugar monitoring is vital to ensure the dose is correct. This can often be done at home, but we’ll often need the dog into the clinic for more intensive testing occasionally. It usually takes several weeks to work out the best dose and treatment regime for any particular dog.
Dietary management is also important (we usually recommend a specialist diabetic diet), as is a very regular routine.
The biggest risk of diabetes treatment is accidental overdose of insulin, which may result in a “hypo” – hypoglycaemic dogs become wobbly, behave strangely, and then collapse. It can, however, be easily treated with glucose syrup on the gums (just like in people).
If you think your dog may be diabetic, make an appointment for one of our vets to check them out as early as possible – rapid diagnosis and treatment gives the best results!