Diabetes in Cats – Symptoms and Treatment
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How Does Diabetes Work?
Diabetes is a complicated condition and understanding it requires a basic knowledge of how food is metabolised within the body. The digestion of food, especially carbohydrates, releases glucose into the bloodstream. A hormone called insulin is secreted so that the glucose can be absorbed into organs where it is used and stored. Insulin effectively unlocks cells so that glucose can move into them from the blood.
Diabetes mellitus can occur from two different breakdowns within this system. Type I diabetes occurs when not enough insulin is released for glucose to be absorbed. Type II occurs when the cells targeted by the insulin are resistant to it, so a normal amount of insulin cannot allow glucose to enter cells effectively. Cats typically develop the latter.
If we compare diabetes to dating, and glucose to a delicious dinner at your favourite restaurant; in type I, you (the cell) wait patiently for your date (insulin) to arrive. But insulin doesn’t pitch. No dinner for you. (You can’t even make toast because you’re a cell.) In type II, insulin arrives but he’s nothing like his profile, at least ten years older and his breath smells. You don’t go on the date. You’re resistant to any charms he may have. You tell yourself you have standards, but you still don’t have dinner.
Both types of diabetic dating disasters result in an excess of glucose in the blood, which is not absorbed, and this leads to a variety of symptoms. Weight loss occurs because glucose cannot be stored in the cells and used for energy. This can be accompanied by hunger in the early stages, or loss of appetite later on. The excess glucose is lost in the urine, and because sugar acts as a solute, it draws water with it, leading to increased urination, dehydration and thirst. That’s why increased urination and increased drinking are two of the earliest and most prominent signs of diabetes.
In severe cases, a complication known as diabetic ketoacidosis can occur. This can be life threatening and requires urgent veterinary attention. The glucose-starved body breaks down its fat supplies for energy, and these are further broken down to ketones, which are acidic. High levels of ketones can push the body into an acidotic state, with many negative consequences. Signs of this can include vomiting, diarrhoea, lethargy, fast breathing and collapse.
Diabetic ketoacidosis is often the way that a newly diabetic cat first presents, because there is no regulation of blood glucose levels. It is less common in established diabetics who are stable and receiving treatment, and generally occurs in these cases when medication is not given, or the body is challenged by an additional condition (such as an infection or cancer).
What Are the Risk Factors for Diabetes?
There are a few factors which play a role in the development of diabetes in cats.
Age – older cats are at much higher risk than young cats.
Obesity – obese cats are up to four times as likely to become diabetic as cats of normal weight (2). Insulin resistance caused by obesity can be reversible (1) and so weight control is one of the most important ways to prevent and also manage diabetes.
Cortisone – cats who are treated regularly with cortisone are more likely to develop diabetes. If we go back to our dating analogy, cortisone is your ex. They can be very helpful in certain situations, such as for a flare up of asthma (or a wedding where you need a plus one), but both can easily become a toxic habit and should be treated with caution. In the same way that a lingering ex can wreak havoc on your dating life, cortisone can increase insulin resistance and the risk of developing diabetes.
Inactivity – a lazy lifestyle increases susceptibility to diabetes.
Gender and Sterilisation Status – male cats are at slightly higher risk than females. Sterilised cats are at higher risk than intact cats.
Breed – some studies show that certain breeds are slightly more predisposed, such as the Burmese (1, 2).
How Is Diabetes Diagnosed?
Diabetes is diagnosed based on clinical signs as well as persistently high levels of glucose in the blood and urine. Screening tests may also need to be performed to check for any concurrent issues.
Measuring blood glucose in cats is complicated by two factors:
Firstly, their blood glucose rises in response to stress, and being at the vet is stressful.
Secondly, cats are often reluctant to eat in hospital and this lowers their blood glucose.
Fructosamine, a more long-term measure of blood glucose, can also be tested. This has the advantage of not being swayed by the stress of a vet visit; but is not ideal in that it shows an average and gives no indication of high and low fluctuations of blood glucose. For this reason, performing a glucose curve is usually advised.
A glucose curve entails tracking the glucose level every one to four hours over the course of a day. Each reading is taken by getting a drop of blood, usually from a small needle prick at the inside edge of the cat’s ear. There are small blood vessels located here which make it easier to get a drop of blood, and there is no hair to interfere with application to the glucose stick. Initially, glucose curves will need to be performed every few weeks to carefully reach the correct dose of medication; but over time they can be reduced to every few months.
Some owners learn to perform the glucose curves at home.
How Is Diabetes Treated?
Diabetes treatment involves giving insulin injections under the skin. Unfortunately, medications which can be given orally are not consistently effective in cats. The insulin has to be adjusted gradually until the correct dose is found, with great care to avoid overdosing, which would result in hypoglycaemia. There are different brands of insulin with different durations of action, and your vet will decide which is best for your cat. The injections are usually given once or twice per day; and sticking closely to the same routine of injections and meals is crucial for the success of treatment.
Diet is also very important in the management of diabetes. A low carbohydrate cat food is recommended to avoid blood sugar surges, and high protein levels have been shown to reduce insulin requirements (1). Wet food is preferable to dry food (2), and palatability is important so that fussy cats are consistent with their caloric intake. For these reasons, KatKin may be a good option for diabetic cats, although there are also prescription diets available so always consult your veterinarian when choosing food for a diabetic cat.
What Is the Long-Term Picture?
Managing a diabetic cat requires commitment from the owner, especially in the initial stages while the dose of insulin is being established. With treatment, the prognosis for surviving diabetes and maintaining quality of life is good. Administering the insulin is generally less problematic than expected, partly because the needle is so tiny that many cats are not bothered by the frequent injections. Some cats enter a state of diabetic remission, where they can be managed on an appropriate diet alone, without need for insulin. If this happens, it generally occurs within the first six months of treatment (2).
As daunting as it may sound at the outset, diabetic cats can live long and happy lives if they are managed with care and consistency. If you have a diabetic cat and would like some advice, feel free to send us a message on firstname.lastname@example.org and we will try our best to help!
Additionally, join our private Facebook Group, the KatKin Club House to connect with like-minded people for support and help. Whether it's diabetes, bringing up a kitten or giving an elderly cat the best life, our Facebook community is the place to chat about all things cat-related!
1. Armstrong, J. (April 1, 2009). Diabetes mellitus in cats: Risk factors and treatment proceedings. DVM360. Retrieved June 30, 2021, from: https://www.dvm360.com/view/diabetes-mellitus-cats-risk-factors-and-treatment-proceedings
2. Cornell Feline Health Center. (2021). Feline Diabetes. Cornell University College of Veterinary Medicine. 2021. Retrieved July 2, 2021, from: https://www.vet.cornell.edu/departments-centers-and-institutes/cornell-feline-health-center/health-information/feline-health-topics/feline-diabetes