Diabetes in Dogs: Signs, Treatment and Daily Management

Canine diabetes mellitus is almost always the equivalent of type 1 in humans: the pancreas stops producing enough insulin, so glucose cannot get into cells and accumulates in the blood.

It requires lifelong insulin, and with good management most diabetic dogs live normal lives.

The signs

The classic four:

• Increased thirst — the most common first sign owners notice
• Increased urination, sometimes with accidents in a previously reliable dog
• Increased appetite
• Weight loss despite eating well

Later signs include lethargy, a poor coat, recurrent urinary tract infections, and cataracts, which develop rapidly and are often what brings a dog to the vet.

Diabetic ketoacidosis is the emergency form: vomiting, profound lethargy, rapid breathing, dehydration, collapse, and sometimes a sweet acetone smell on the breath. This needs intensive care immediately.

Who gets it

• Middle-aged to older dogs, typically seven to ten at diagnosis
• Unspayed females, because progesterone antagonises insulin. Spaying is usually recommended at or soon after diagnosis and can significantly improve control
• Breeds — Samoyeds, Miniature Schnauzers, Miniature and Toy Poodles, Bichons, Keeshonds, Australian Terriers, Cairn Terriers and Dachshunds appear over-represented
• Dogs who have had pancreatitis, which can damage the insulin-producing cells
• Dogs with Cushing’s disease
• Dogs on long-term steroids
• Obese dogs, though the link is weaker than in cats

Diagnosis

Persistently raised blood glucose plus glucose in the urine, alongside the clinical signs. A fructosamine test shows average glucose over the preceding two to three weeks, which distinguishes genuine diabetes from stress-related glucose elevation.

Your vet will also look for concurrent problems — urinary infection, pancreatitis, Cushing’s — which affect how well the diabetes can be controlled.

Treatment

Insulin injections, usually twice daily, given under the skin.

Owners are almost universally alarmed at the prospect and almost universally fine within a fortnight. The needles are very fine, the injection is under loose skin at the scruff or flank, and most dogs barely notice — particularly if you pair it with food.

The rules that matter:

• Same times every day, usually twelve hours apart
• Give it with or just after food, not before, so you know the dog has eaten
• If your dog does not eat, do not give the full dose. Ring your vet. This is the most important rule
• Store insulin as directed, usually refrigerated, and never freeze it or shake it. Roll the vial gently
• Use the correct syringes for the insulin concentration. U-40 and U-100 syringes are not interchangeable, and mixing them up causes serious dosing errors
• Never change the dose yourself without veterinary instruction

Hypoglycaemia: know this before you need it

Too much insulin, or a missed meal, causes blood sugar to fall dangerously.

Signs: weakness, wobbliness, disorientation, trembling, hunger, glassy eyes, seizures, collapse.

What to do: if the dog is conscious and can swallow, rub honey, glucose syrup or sugar solution onto the gums, then feed a meal, then ring your vet. If they are unconscious or seizing, rub syrup on the gums — do not put anything in the mouth they could inhale — and go to a vet immediately.

Keep glucose syrup in the house and in the car. Every diabetic dog’s household should have it.

Feeding

Consistency is the whole strategy.

• The same food, the same amount, at the same times every day
• Two meals, timed with the insulin
• A diet with consistent, moderate carbohydrate and good fibre. Veterinary diabetic diets are formulated for this; your vet will advise whether one is needed
• No variable treats. If you give treats, give the same ones in the same amount at the same times
• No table scraps, particularly anything fatty, given the pancreatitis association
• Keep them lean

Monitoring

• A daily log — appetite, thirst, urination, energy, weight, and any events. This is the most useful thing you can bring to a check-up
• Measure water intake weekly. It is the most sensitive home indicator of control
• Glucose curves, done at the practice or at home, to see how the insulin behaves across a day
• Continuous glucose monitors are now used in dogs — a small sensor worn for a fortnight, giving continuous readings. Ask whether it suits your dog, because it removes a great deal of guesswork
• Fructosamine periodically
• Regular urine checks for infection, which diabetic dogs get frequently

Cataracts

The complication owners are least prepared for.

Around three quarters of diabetic dogs develop cataracts within a year of diagnosis, and they can appear over days. They cause blindness, and unlike the human version they are not related to how well controlled the diabetes is.

The good news: cataract surgery in dogs is highly successful, and many diabetic dogs regain excellent vision. If it is an option for you, discuss it early, because outcomes are better before secondary inflammation sets in.

If surgery is not an option, dogs adapt to blindness remarkably well — keep the furniture where it is, gate the stairs, and use voice cues.

Living with it

The first month is the hard part: learning to inject, adjusting doses, and worrying. After that it becomes routine, and most owners describe it as much less disruptive than they feared.

The things that make it work:

• A fixed daily routine, which also makes life easier if someone else has to cover
• Written instructions for anyone caring for the dog
• A relationship with your practice, since the first few months involve adjustments
• Insurance, if you have it, and a realistic budget if you do not — insulin, syringes and monitoring are an ongoing cost

Most diabetic dogs, well managed, have a normal life expectancy and a good quality of life. It is a routine, not a tragedy.