Diabetes in Cats: Common Causes & Treatment Options

Last Updated on: July 18, 2024

This is Stephen

Any guesses as to what breed this spunky hunk of burning love is?

You got it, he’s a Burmese cat.

Stephen is… Wait, I just lost my train of thought looking at that face, THAT SMOOCHALICIOUS FACE!!

Okay… So this little red picture of perfection didn’t land himself in an article on diabetes in cats by accident.  Burmese cats, (particularly males), are over-represented when it comes to this disease.  Before you call bullshit, my American friends, this curiously this only applies to Burmese cats in AustraliaNew Zealand and the UK.

Here in the land down under, one in ten Burmese cats over eight years of age is diagnosed with diabetes.

The major risk factors for diabetes in cats are inactivity and obesity.  Put another way, the lazy, fatty boombah cats are the ones most at risk.  Obese cats are 3.9 times as likely to develop diabetes compared with cats of optimal weight.  Now while there are a multitude of ‘fat cat’ images ripe for the picking on the world wide web, I really don’t believe I need graphic images of what amounts to animal abuse to make my point.

We shall call the above cat Puddin.  Puddin’s owners think food = love.  Either that, or Puddin has a black belt in the feline art of food theft.  In any case, Puddin is a Puddin.  This is not healthy!  If you’re not sure whether your cat is overweight, check out this body condition score chart from WSAVA

Lucky for Stephen, he has an AMAZING mumma (who also happens to be a veterinary nurse) who will keep him in tip top shape, so he really has nothing to worry about (so stop worrying Stephen, I can see it written all over your face!)**.

Anyway, partly due to the tenuous link via his breed, but mainly because I loves him, I shall lightly pepper the remainder of this article with portraits of Stephen*. You’re welcome.

*And the walls of my home.  And that little photo spot in my wallet where my kids should be..
**  It would be remiss of me not to mention also, that Stephen’s father is such a glorious example of good looks, sharp intellect and a razor sharp wit all bundled up neatly into one bearded package that Stephen may, in fact, one day be president.

What Exactly is Diabetes in Cats?

Ok, so firstly, what is diabetes?  Its proper name is diabetes mellitus, with the word diabetes meaning ‘to pass through’ and the word mellitus meaning ‘sweet’.

I think basically the translation is ‘sweet urine’, but I don’t know what kind of sicko looks at a fresh, warm specimen and thinks, ‘I’m actually a little parched right now, nobody’s looking, might just take a sneaky sip’.  Actually, Wikipedia just answered that question for me, a guy named Thomas Willis in 1675.  Seriously Tom, I just, no Tom… No.

But I digress.

In a normal, healthy, non-diabetic cat (or human for that matter!), the glucose from food enters the bloodstream, and this triggers the pancreas to release insulin.  The insulin then allows cells of the body to take up the glucose from the bloodstream.  It does this by binding with a receptor on the outside of the cell that tells little glucose transporters to come and get the glucose.

The cells then use the glucose for energy or store it for later.  When things go wrong in cats their disease is similar to type 2 diabetes in people.  They develop insulin resistance, which means the pancreas is pumping out loads of insulin, but the cells, particularly in muscle, fat and liver, just aren’t responding to it very well…

The sustained humongous demand for insulin in these cats just to get a little glucose into cells makes the pancreas angry about being ignored.  Well actually it just gets really tired, and so it stops working properly.   The pancreas can’t secrete as much insulin any more, and we end up with diabetes.

Now the glucose isn’t getting into the cells to meet energy requirements.  So these cats are generally so hungry they could eat the ass out of a low flying duck.  Even with this increased appetite they will still lose weight, because they need to break down body stores of protein and fat to make their own glucose for energy.

Now the kidneys, which normally reabsorb any glucose they see back into the blood stream, can no longer keep up with the crazy high levels.

Mr Kidney enjoyed his job putting glucose back into the bloodstream until the Great Glucose Stampede of 2014

Glucose ends up making its way into the urine (hence Tom’s delicious sugary beverage).  The glucose molecules love water and drag it along with them, so the cat ends up peeing a lot more. Because the cat is peeing a lot more, it has no choice but to drink a lot more.  If for some reason the cat doesn’t have access to enough water, it will become dehydrated and unwell very quickly

Aah yes of course! Wait, no, I still have no idea what you’re talking about.

What are the Signs that my Cat may have Diabetes?

In most cases we’ve got a cat that is initially overweight (although not always), but has been gradually losing weight despite a really hearty appetite.  Kitty is also likely to be super thirsty, and you may find you’re refilling the water bowl much more frequently than you used to.

The litter tray is always wet or maybe there are even little accidents happening around the house because your cat needs to pee a lot more.  But he’s bright and happy.  This is the situation early on, anyway.

Sometimes these signs are subtle and occur very gradually though.  If they go unnoticed, the disease progresses and we end up with a situation called diabetic ketoacidosis, or DKA.  These guys are really, really sick.  They are usually depressed and dehydrated, and may have vomiting and diarrhoea.

DKA can become deadly in a short time, and a period of fairly intensive treatment in hospital may be required to pull them through it.  However, if you’ve hung in this far and read all the way through my ramblings, you know what to look out for and will be able to pick it up early if your cat does become diabetic.

Feline diabetes discovered early is very manageable, and in fact many cats go into remission.

How Can My Veterinarian Tell if My Cat has Diabetes?

There are two main test results required for a vet to be able to diagnose diabetes in a symptomatic cat:

  1. A high fasting blood glucose (i.e. loads of glucose floating around in their blood even when they haven’t eaten recently)
  2. Glucose present in their urine (known as glucosuria)

Testing these parameters is a piece of cake!  See what I did there?  But here’s where it gets tricky.  Cats can get enormously stressed out by a visit to the vet (kind of like I feel about sitting in the dentist’s chair), and a really important effect of this stress can be a transient elevation in their blood glucose, which can even be significant enough to see glucose spilling over into the urine.

What this means is that cats who do not have diabetes may have a high blood glucose reading, and even occasionally glucose in their urine.  These tests aren’t always diagnostic on their own.

It is best to run a full blood profile rather than just checking the glucose alone.  This assists us with detecting any other illnesses that may either be the sole cause of your cat’s problems or could just be lurking around complicating the situation.

If there is any doubt about the diagnosis of diabetes, a good test to do next is a plasma fructosamine level.  This test gives an estimate of the ‘average’ blood glucose over the preceding five to ten days, so takes out the “cheese and whiskers! I’m at the vet clinic!!!” freak out factor.

Sadly, not all cats are won over instantly by my great looks and razor sharp wit. 

Ok, So We have a Diagnosis, What Next?

Seriously Stephen, I’m starting to wonder what I pay you for!

This is the stage where it’s really important that your vet takes some time to sit down with you and go through things.

There is more than one option, and to make the right choice for you and your cat, you need to be properly informed.  If you have a very very sick, old cat with diabetic ketoacidosis and maybe even other things going on, your choice may not be the same as if you have a healthy, younger cat that has had diabetes picked up on a routine blood test.

Broadly speaking, the options are to treat, or not to treat.  If you elect not to treat a diabetic pet, that’s ok, and no one should judge you for making this difficult decision.  However,

a sick cat can’t be left untreated

They may be pretty good at hiding it, but they will be feeling miserable.  Imagine being constantly thirsty and needing to pee all the time, always being hungry and never being able to satisfy this hunger.  Diabetic humans report feeling nauseous and unwell when their blood glucose is high, as well as feeling listless and tired.

On top of this, cats can have recurrent urinary tract infections, go into kidney failure, develop high blood pressure, go blind, and experience painful diabetic neuropathy if left untreated.

They could go on like this for a year, or they could develop diabetic ketoacidosis and die within a week.

So if you elect not to treat your diabetic cat, the humane option is euthanasia.  I know this may sound extreme, but as a veterinarian it’s my job to advocate for the animal – and it’s not ok to let them suffer.

I’ve put together a list of things you should discuss with your veterinarian if your cat is diagnosed with diabetes.  It is by no means exhaustive, but I’ve conveniently covered myself by adding the last point.

Treating The Diabetic Cat – What’s Involved?

There are four main things we need to cover:

  • Diet
  • Insulin
  • Exercise
  • Monitoring

Which Food Is Best?

Changing the diet and finding a good diabetic specific cat food can make a massive difference for these felines.  They need to eat a diet that is low in carbohydrates and high in protein.  There are commercial diets that have been designed and balanced specifically for diabetic cats.  These are a really good choice because not only are they convenient, but their caloric content is pretty consistent, and this is so crucially important for managing the diabetic cat.

Some cats might not fancy commercial food, fair enough, and for these fussy felines a home cooked diet may be best.  In these cases an appropriate, balanced and complete diet needs to be worked out with your vet.

Do I Have to Give my Cat Injections?

For most cats with diabetes, injections of insulin morning and night is the best treatment option.  Occasionally cats will not need it if managing their obesity or withdrawing a drug that was causing problems sorts out their glucose intolerance, but this is not really that common.

Some cats (maybe 10 – 20%) may respond to oral medications called hypoglycaemic agents.  However, their use is controversial, because they increase the amount of insulin released by the pancreas and so can wear it out faster.  I have personally never used these drugs in a diabetic cat.

So do you need to give your diabetic cat injections?  My answer is yes.  But wait, don’t panic, it’s really easy, I promise!

Of course your vet will show you how it’s done and give you the opportunity to have a practice at the veterinary clinic.

Which Insulin Is Best for Cats?

There are many different insulin preparations, and they can come from cows, pigs, or humans (the latter is from recombinant DNA technology).  The main difference between the products is their duration of action.  The choice of insulin is a really up to you and your vet, but my personal preference for maintaining diabetic cats is glargine insulin (the one we use is called Lantus).

It is particularly good for cats that tend to graze throughout the day rather than eating their meal in one sitting.  Another good choice is protamine-zinc insulin, which many cats are well managed on.

Regardless of what type of insulin you use, for it to work best the injections will have to be done twice daily.

What About Exercise?

Bahahaha you may say, exercise!  We’re talking about cats here, not dogs!  But it’s still important to be aware of the effect of exercise on blood glucose.  Exercise lowers insulin requirements.  With cats, over-exercise is unlikely to be problem, and encouraging moderate, consistent exercise can be helpful.

Consistency, Consistency, Consistency, Consistency, Consistency

The overall goal in managing diabetes in cats is to keep blood glucose levels fairly stable, without allowing the cat to become hypoglycaemic (that blood sugar is toooo low) or hyperglycaemic (that blood sugar is toooo high).  We want blood sugar that is juuuuuust right!

So the easiest way to think about it is that insulin brings the blood glucose down, and food brings it up.  We need to match these in amounts and timing to keep everything nice and balanced.

The most essential part of managing a diabetic cat is CONSISTENCY

Sorry for getting all shouty with the caps there, but it’s important. We need a very consistent routine in terms of:

  • Diet
  • Insulin administration
  • Exercise

Keeping the type, amount and timing of food your cat eats the same every day is just as important as giving the right amount of insulin at the right time.

Generally the best time for a meal is one to two hours after each insulin injection, because this is just before the peak insulin activity.  This varies with the type of insulin chosen and is something you should discuss with your veterinarian.

Monitoring Your Diabetic Cat

There are a few ways to monitor diabetic control.

  1. Water Intake – If the diabetes is being adequately controlled, kitty should be a lot less thirsty.
  2. Body Weight – A very simple thing to watch, and if it’s stable then the diabetes is probably fairly well controlled.
  3. Single Blood Glucose Measurement – You want to do this at the time you expect the insulin to be having its maximal effect, so for a cat that has insulin twice daily this is around four to six hours after a dose.  A good reading for a cat at this time is between 7 and 10 mmol/L (or between 180 and 234 mg/dl).  See below for how you can do this at home.
  4. A Glucose Curve – Serial blood glucose measurements taken throughout a day is a more sensitive estimate of diabetic control and is done in the veterinary hospital.
  5. Urine Glucose – This is of limited value because it’s not a very sensitive test and can be affected by too many other factors.
  6. Fructosamine – This blood test gives an idea of the average blood glucose over the preceding five to ten days.

It used to be that every diabetic cat had to visit the vet clinic regularly for a glucose curve to monitor how they were going.  This means staying in hospital for a day and having repeated blood samples taken every couple of hours to plot what is happening to the blood glucose in response the the insulin they are being treated with.

While this is a useful method and certainly has it’s place, it is becoming more and more common for owners to monitor their cats at home.

This is really helpful, because it takes away that stress-induced hyperglycaemia I talked about earlier that can really mess with results.  On top of this, some cats don’t cooperate because they are too stressed to eat their normal meal in hospital, and really, it’s just nicer for them to be able to stay home!

Can Diabetes in Cats be Cured?

A lot of cats diagnosed with diabetes mellitus will have it for the rest of their lives, and I think owners need to be prepared for this outcome.  BUT, it is possible for them to go into remission if they are caught early, and up to half of cats picked up before things have been going on for too long and treated with insulin and a high protein, low carbohydrate diet will achieve this.

Any Questions?

Please stay tuned for Part II of my Diabetes in Cats series – How To Care for the Diabetic Cat.  If you want to be sure not to miss it you can sign up for my mailing list here.

If you have any questions or comments, please feel free to leave them in the comments section below, and either myself or Stephen will get right back to you!  I can’t guarantee Stephen knows anything about anything though.

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