Dogs’ and cats’ endocrine systems work very similarly to humans’, and they experience similar disorders of the endocrine organs as humans do. This includes diabetes mellitus. Diabetes originates and presents in different ways between dogs and cats, but the mechanism is the same: the body is unable to use the glucose in the bloodstream. This occurs because either the pancreas does not produce enough insulin or the body is resistant to insulin secretion.
What is diabetes?
Diabetes is a chronic disease characterised by the body’s inability to manage the glucose levels in the bloodstream. When the animal consumes food, the pancreas releases enzymes and hormones to assist with digesting the food. One of these hormones is insulin. Insulin is released from the pancreas and circulates in the bloodstream, facilitating the uptake of nutrients, especially carbohydrates (sugars or glucose).
However, sometimes the pancreas cannot secrete sufficient insulin to deal with the glucose (deficiency), or the body does not respond to the insulin that is secreted (resistance). This means that the glucose and nutrients consumed aren’t absorbed efficiently, and remain in the blood for an abnormal amount of time. This prolonged high blood sugar is called hyperglycaemia and also causes glucose to be excreted in the urine (glucosuria).
Can dogs and cats have diabetes?
Diabetes mellitus is a disorder of the endocrine system in mammals. Roughly one in every 250 dogs or cats develops diabetes mellitus, and while the disease has the same outcome (too much glucose in the bloodstream), it presents differently between the different species. Virtually all dogs suffer from the insulin-dependent form of diabetes, where insulin in the body is deficient and must be administered. Around fifty percent of cats with diabetes have the non-insulin-dependent form, where the body produces insulin, but is resistant to it and it does not produce the physiological effects that it should – i.e. stabilising the blood sugar.
What causes diabetes in dogs and cats?
The onset of diabetes in dogs and cats can be caused by multiple factors. It is more common in older animals, and often occurs alongside another disease or condition, such as bacterial infections, pregnancy, Cushing’s syndrome, kidney failure or liver failure. There are genetic, lifestyle and environmental influences, while underlying medical conditions also play a role in the onset of diabetes.
Canine diabetes may have a genetic component, making some breeds predisposed to developing diabetes. Breeds such as miniature poodles, Dachshunds, schnauzers and beagles appear to be more susceptible to the disease.
Sometimes, diabetes can be immune-mediated, meaning the body attacks its own cells that are necessary for insulin products. Pancreatitis is another commonly involved condition with diabetes in both dogs and cats. Other health conditions that can increase the dog or cat’s risk of developing diabetes include:
- hyperthyroidism in cats
- hypothyroidism in dogs
- kidney disease in cats
- Cushing’s disease in dogs
- long-term use of corticosteroids
- dental disease
- skin infections
Feline diabetes is very often associated with obesity, which is one of the main reasons why pet owners should not let their cats get overweight. Diabetes in cats that is diagnosed and treated is often only a temporary condition. Even stress can create a state of high blood glucose, which then suppresses the secretion of insulin, which causes high blood glucose –a vicious cycle. However, when insulin is administered and blood sugar levels return to normal, further treatment becomes unnecessary. This kind of diabetes onset can only be determined retrospectively after treatment has begun.
How do cats act when they have diabetes?
There are a number of symptoms a cat will have when they develop diabetes, which include:
- increased thirst
- increase in frequency and volume of urination
- increase in appetite, followed by a decrease in appetite
- weight loss – cats appear thin
- decreased frequency of grooming, so their coat appears rough
- increased amount of shedding
- vomiting
- muscle wasting, weakness
- staggering, collapsed limbs (diabetic neuropathy)
- bladder infections due to glucose in the urine (encourages growth of bacteria)
- delayed wound healing
- prolonged diabetes can cause cataracts and blindness
- enlarged liver
Blood sugar fluctuations can cause cats to become irritable and aggressive, or to reduce once energetic and playful cats to lethargic and solitary pets. It’s important for owners to notice changes in behaviour as well as personality, and report these to the vet.
What are the signs of a dog with diabetes?
Dogs with diabetes present similar symptoms to cats, which include:
- increased appetite
- increased thirst
- increased frequency and volume of urination
- dehydration
- weight loss
- recurring/chronic infections
- enlarged liver
- cataracts and blindness
- delayed wound healing
- neuropathy/nerve damage in limbs
- depression
- tissue damage
What is the treatment for pets with diabetes?
The main purpose of treatment for diabetes is to regulate blood sugar levels and ensure they stay within a healthy range, as they would in a healthy pet. Proper treatment should also eliminate the symptoms of excess thirst and urination, and restore the animal’s weight, condition, and overall quality of life. This is done by administering insulin at the correct dosage and intervals. The dosage will vary depending on each individual animal, and is determined by performing a glucose curve: checking the blood glucose every two hours over the course of one day, and putting the values into a graph to assess the fluctuations. The vet will adjust the amount and frequency of feeds with insulin administration to avoid the lows and highs in the curve as much as possible. It can take up to six months to find the ideal dose and timing of insulin administration.
It is the pet owner’s responsibility to give their diabetic pet their insulin at the dosage instructed by the veterinarian. Insulin must be refrigerated until it’s time to inject it. It’s administered via a special insulin syringe, and must be given at the same time every day. Routine is critical in the management of diabetes – feeding times and the timing of the insulin treatment must be kept as constant as possible, as this is what keeps the animal’s blood glucose in a constant healthy range.
The amount of insulin your pet should receive will be determined by their weight and how active they are. If your pet is obese, they will need to lose weight and their insulin will need to be adjusted down to align with their new, healthy weight. Their feeding and activity levels will need to remain as constant as possible, undertaken at the same time and – exercise-wise – at the same intensity and for the same duration daily.
Not all diabetic cats are treated with insulin. There is also a medication that is given orally, which increases the excretion of blood glucose via the kidneys. This ‘sodium-glucose cotransporter 2 inhibitor’ (or SGLT2) also works to lower the amount of glucose in the bloodstream by preventing the kidneys from reabsorbing it. Cats that have hyperglycaemia, but are otherwise healthy, are given this medication. It is not given to dogs.
If an overdose of insulin is given, it causes the blood sugar to drop, leading to hypoglycaemia with symptoms of weakness and shivering. In extreme cases, the animal will have seizures.
How is diabetes in pets managed?
Diabetes is a chronic disease that usually requires lifelong management, but with cooperation between the vet and the pet owner, and home compliance on the pet owner’s part, the pet can live a relatively long and healthy life after diagnosis.
The prognosis for a diagnosed pet depends on the presence of a concurrent disease, the response to treatment, and the owner’s commitment to their pet’s treatment. Long-term prognosis in cats is generally guarded, with the average survival time being two years. Dogs can live for a number of years after diagnosis, with those years being relatively normal and happy, as long as their diabetes can be appropriately managed.
When the disease has been properly diagnosed and a formal treatment and management plan has been implemented, the prognosis is quite good. The most dangerous period is before the most efficient dosage of insulin has been found – when the blood sugar is fluctuating. However, most pets respond well to therapy and, as long as their treatment is consistent and correct, they will have an excellent quality of life. This is hugely dependent on their owner’s willingness and ability to offer their time, money, and effort to treat their diabetic pet.
What should you not feed a dog with diabetes?
Managing diabetes is not only about administering medical treatment. Diet and exercise for the purpose of keeping the animal lean are a priority, as obesity can worsen the condition. A diet that is low in calories and high in fibre is ideal. Complex carbohydrates slow down the absorption of sugar and minimise blood sugar fluctuations. Veterinary prescription diets are readily available from the vet, and assist greatly in the treatment and management of diabetes.
Routine exercise is also helpful in controlling blood sugar and keeping the diabetic animal healthy. Feeding, medicating and exercising at the same time every day (for the same duration) helps to maintain the animal’s weight and to increase insulin sensitivity. For example, it’s better to take your diabetic pet for a short walk every day compared to one long walk once a week. Strenuous exercise can consume too much blood glucose, causing the animal’s blood sugar to drop, leading to hypoglycaemia.
Unfortunately, diet and exercise alone cannot be used to manage the diabetic pet. Insulin administration is necessary and the pet’s blood glucose needs to be regularly monitored to ensure their blood sugar is staying in the healthy range.
If you are concerned about these symptoms in your beloved pet, make an appointment with the vet to determine the cause and to find the appropriate treatment.