The Signs, Diagnosis & Types of Diabetes Mellitus in Cats

Diabetes mellitus (DM) is a common metabolic disease. At its core, it is a chronic condition of the body with high blood sugar and a corresponding lack of metabolic control to respond.

If left untreated it can lead to life-threatening complications such as cardiac disease, nerve damage, loss of muscle control or dangerous changes to electrolytes and acid-base status.

Cat owners should be able to recognize signs for this disease. The earlier the DM is detected, the better the prognosis your cat would have.

black cat

The Science

Diabetes is a disease that alters the way we regulate glucose. Glucose is the “energy currency” the cells in the body depend on. As a result, the body has developed crucial pathways that regulate how glucose is stored, synthesized, and transported.

Glucose is derived from nutrients. The food cats eat eventually breaks down into its constituent components. This could be fats, proteins or carbohydrates eventually made into glucose by the digestive system of the cat.

Insulin, which is produced by the pancreas, is needed by the body to take those sugars and place them where the body needs them the most. With diabetes, the body either can’t produce insulin on its own or becomes resistant to its effects.

Types of Diabetes

There are two types of diabetes: type 1 and type 2. These classifications are recognized in veterinary medicine as well.

Type 1 Diabetes is when the body’s own cells attack and destroy the insulin-secreting beta cells in the pancreas – leading to the body unable to produce insulin.

This is a type of autoimmune disease and is more commonly referred to as Juvenile Type Diabetes in humans. Type 1 Diabetes is exceedingly rare in cats.

The most common type of diabetes in both people and cats is Type 2 Diabetes (1). In this form of the disease, various factors lead to cells building resistance to insulin.

The cells will not respond to the insulin being produced and the glucose would remain in the blood instead of being stored or transported into the cells as what normally would happen in the presence of insulin.

It is important to note that diabetes can also result from several other disease processes. Other metabolic diseases, some cancers, and even Pancreatitis can destroy the beta cells or alter the way they function – leading to Type 2 Diabetes.

Type 2 Diabetes is more common in overweight(1) and older cats and males are slightly more represented than females. By far the most important of these predisposing factors is weight, causing obese cats to be 2.9 times riskier to get diabetes(1). 

Keeping your kitties at a healthy weight is the number one thing you can do to maximize their chances of living a long and healthy life. For every pound that a cat is above its ideal, its likelihood of developing insulin insensitivity (and eventually diabetes) increases by roughly 13%.

The reason behind this association is not fully understood, but it is important to recognize that fat cells secrete their own messenger molecules and hormones. Your cat’s extra fat increases fat-derived hormones that interfere with the normal cell signaling pathways leading to insulin resistance and diabetes eventually.

Russian Blue, Abyssinian, and Norwegian Forest cat breeds are predisposed to developing diabetes(1). If you own any of these, it is important to keep a close eye on them and watch for signs of early diabetes.

Symptoms of Feline Diabetes Mellitus

It’s important for owners to understand a little about the ongoing background processes in disease. We believe that the more we understand about what’s going on, the easier it is to buy into treatment protocols.

It also helps to keep everyone more aware of our pet’s home life, diet, and general lifestyle and how each is affected by the disease.

While these signs are fairly easy to see in single cat households, things become more difficult the more cats you have in your home; with multiple cats sharing litter boxes or eating and drinking from the same bowl.

  1. Polyphagia

Poly means many and phagia generally refers to eating; so this literally means your cat is eating more than usual. If you feed your cat free choice, you may notice that the bowl empties faster.

Measure your cat’s dose. It’ll race to the food bowl when it hears the krinkle of a bag or the sound of a can being opened.

Cats may give you more attention when you are eating a meal. Other signs include begging for treats or just increased interest in food.

  1. Weight Loss

This seems contradictory because Type 2 Diabetes is seen in overweight cats. What gives?

Remember, diabetes causes your body to inadequately respond to insulin. This leads to cells not getting enough glucose – leading to an inability to do their duty.

Though there is an abundance of glucose in the cat’s blood, the cells don’t “listen” to messages stating that insulin is on its way, so the glucose can’t get into the cell.

The cells wouldn’t receive the nutrition they need. They send out their own messenger molecules in the blood that scream, “I’m hungry and I can’t do my job!”

This directs the brain to tell the body to eat more since the brain acts like there isn’t any glucose around. It needs food to make glucose so that your cat will want to keep eating.

Since a cat with diabetes cannot adequately utilize insulin, the body turns to other parts to get the energy it needs. Your diabetic feline will lose weight even though it’s eating more than it should.

Without being able to use all of the extra glucose, the body’s metabolism will break down tissues in the body (mainly fat and muscle). This contributes to weight loss and “wasting”.

A way to watch out for this is to buy a small scale and weigh your cats once a month. The ability to monitor trends in your cat’s weight might encourage better dietary choices and may signal when a chronic process could be if weight loss is noted.

There can also be instances where your cat will have lost its appetite; also resulting in weight loss.

  1. Polyuria (Excessive Urination) and Polydipsia (Drinking More Water)

Another sign that your cat may have diabetes is if you notice your cat urinating more often, or if there are larger urine clumps in the litter box. The excessive sugar in the bloodstream spills over into your cat’s urine and pulls extra water with it; leading to more urine production.

This process also results in dehydration; making your cat thirsty all the time.

Once blood sugar gets high enough, it “spills over” into the urine – causing a condition known as glycosuria. This is when glucose is present in the urine and might signal diabetes in unhealthy cats.

Glucose being in a cat’s urine can also lead to something called osmotic diuresis. This means there is more dissolved “stuff” in the urine.

The principle behind osmotic diuresis is that the excess water from the body is being drawn into the urine because it has such a higher concentration gradient than normal.

Because of this, more water is “sucked” into the urine, the cats use the litter box more, and the body has to compensate by drinking more water. This is because your cat’s body is losing so much extra water through the increased urination.

  1. Lowered Or “Plantigrade” Stance

Cats usually walk on their tiptoes with their hind feet. When diabetes goes undetected, it may result in damage to nerves in the hind limbs, causing cats to walk flat-footed with their back feet. This is called a plantigrade stance.

5. Hyperglycemia

Hyperglycemia refers to blood sugar levels being too high which is a result of diabetes going undetected and untreated. Hyperglycemia leads to the aforementioned signs, but can also make cats lethargic or tired all the time with less energy than usual.

6. Diabetic Ketoacidosis

Diabetic ketoacidosis is a severe complication of diabetes. Since the body can’t utilize sugar, it starts to break down fat.

The by-product of fat breakdown is called a ketone. A high level of ketones in the body is toxic, leading to a lack of appetite and vomiting.

Fortunately, many cats can be diagnosed with diabetes before this complication results. However, if it does happen, it is considered a medical emergency.

Diagnosing Diabetes

Thankfully diabetes is easy to diagnose. If you have noticed some of these signs in your cat, it’s best to take it to the vet so they can test your cat for diabetes.

Your vet will fully examine your cat and will also ask for a complete health history to help in proper diagnosis. Blood and urine samples will often be taken to test for excessive glucose levels.

  • Bloodwork

If you go to your vet and your primary complaints consist of some of the signs mentioned above, your vet will almost assuredly want to run some bloodwork.

If the blood glucose level is above a certain threshold, then, it is considered diagnostic confirmation of a cat being positive for diabetes.

These tests are very routine and as such, aren’t usually too pricey. The vast majority of vet clinics will have the ability to run the tests on site and you can have results within half an hour.

You might catch your cat in a pre-diabetic stage. This is when your cat’s blood glucose level is higher than normal but not considered high enough to be truly diabetic. It means that insulin resistance is developing.

Proper intervention can halt true diabetes from manifesting. You can make lifestyle changes to increase the chances of your cat’s sickness not progressing into true DM.

  • Fructosamine Tests

Since cats can often be stressed at the vet’s office which can elevate blood sugar levels, another test called fructosamine may be recommended. Fructosamine levels are not affected by stress and can help see if a cat’s blood sugar levels have been chronically elevated.

  • Urine Test

At the time of diagnosis, most cats will have high levels of glucose in the urine as well. A urine test can also check for ketones to make sure your kitty has not developed a severe complication of diabetes, as previously discussed.

  • Checking Diet History

Your vet might suggest looking at your cat’s diet history. They’ll want to know what you’re feeding your cat, so take a picture of the food label or jot down the name of the food before you go into the clinic.

Your vet will look at the guaranteed analysis of the food label to see what the mix (consisting of carbohydrates, fats, and proteins) nutrients are. They will do this to see if it is appropriate for your pre-diabetic cat.

Your vet might also look at the caloric content. They would compare this number to the amount your cat is being fed to make sure it is not consuming too many calories

The ideal diet would be lower in carbohydrates; more so than your typical cat food. This is in order to minimize the amount of glucose entering the bloodstream after each meal.

Treating The Diabetic Cat

Fortunately for diabetic cats, treatment is very effective at controlling and managing the disease. Studies have proved that large majority of newly diagnosed diabetic cats can actually achieve remission from the disease with proper insulin therapy and dietary changes(1, 2). 

There are a lot of factors in determining whether or not your cat, in particular, will eventually go into diabetic remission. The fact is, diabetes doesn’t necessarily have to be a lifelong disease you and your cat will have to live with.

  • Prescription Diet

A diet higher in certain types of fiber will help to curb blood glucose elevations after eating keeping sugar levels more even during the day. These diets may also be lower in carbs and higher in protein.

Most over-the-counter diets cannot achieve the proper percentages of nutrients needed.

  • Insulin Injections

Besides diet changes, the cornerstone of diabetes treatment involves administering extra insulin to your cat to help keep blood sugar at an acceptable level.

What is an acceptable level, you may ask? It’s the proper dose of insulin that brings your cat’s blood sugar down to the point where clinical signs we talked about above are no longer present.

Determining the proper level of insulin is one of the trickier points in managing your cat’s diabetes. This may require several day-long visits at the vet hospital to find that sweet spot.

The primary method for determining the amount of insulin your cat needs is conducting a test called a glucose curve. Your cat would be fed a normal meal in the morning and a small amount of blood would be collected to measure the blood sugar afterward.

Based on the results, your vet would select a type and dose of insulin to administer directly to your cat. This would be after the first blood sample is taken.

  • Blood Sugar Monitoring

After the insulin is administered, your vet would periodically draw blood samples throughout that day and plot the results on a graph. The ideal dose of insulin would drop your cat’s blood glucose levels to an acceptable range and keep it there for the majority of the day.

As all cats are unique, the first glucose curve won’t necessarily identify the ideal dose of insulin for your cat. It may need to be run a few times in order to find the amount of the drug.

This can be frustrating for owners who expect a definitive answer after paying for one glucose curve test. But once the right amount and the right type of insulin is found, you will rest easy because you know you are doing everything right to give your cat the best chance at a comfortable and healthy lifestyle moving forward.

  • Controlled Feeding

Meal feeding only in the morning and evening is extremely important to prevent any blood sugar spikes in the middle of the day. You will have trouble controlling diabetes in your kitty if it is eating throughout the day.

  • Weight Management

It’s important to make sure your cat is at an appropriate weight. Your vet might institute a feeding plan for your cat if your vet deems it necessary to allow your cat to slowly come down to its ideal body weight.

Some vets may also discuss drug therapy aimed at sensitizing the body. Instead of giving extra insulin to the diabetic patient, there are some drugs that allow the body to use the existing insulin being produced to work more efficiently in the body.

These drugs increase the amount of natural insulin produced by the pancreas. The insulin would have a stronger response to the cells and this would increase glucose uptake in the process.

If your cat is deemed to be in the prediabetes stage, it is important to get periodic blood work. This will gauge the effectiveness of any therapy possibly used.

What Are The Causes And How To Prevent It?

  • Lack of Exercise

Your kitty may develop diabetes if it’s not getting enough exercise. Cats need to be active so they are able to use the insulin in their body more efficiently decreasing the risk of diabetes.

  • High-Carbohydrate/Low-Protein Diet

Carbohydrates are complex sugars found in all pet foods to some degree. However, foods that are too high in carbohydrates can be detrimental.

Your cat’s pancreas will produce excessive insulin when it constantly eats food high in carbohydrates which may lead to diabetes. If this is combined with a low protein diet, your cat will have no avenues to get the energy it needs.

Your cat should have a low-carbohydrate / high-protein diet to lessen the risk of diabetes. This will also help manage glucose levels in your cat’s diet.

  • Pancreas-Related Causes

Sometimes, the cats’ pancreatic cells are attacked by their own immune system which affects the production of insulin and may result in type 1 diabetes.

Similarly, if a cat develops pancreatitis, the inflammation can damage insulin-producing cells in the pancreas which can also lead to type 1 diabetes.

  • Medicines For Other Illnesses

If your cat has asthma or allergies, some medicines that can help with these conditions can predispose it to diabetes. This is especially true of steroids like prednisolone.

This is why it’s best to keep a good working relationship with your vet: to help your allergy-prone kitty while reducing the risk of diabetes.

  • Cushing’s Disease

Cushing’s disease involves an overproduction of cortisol. An overproduction of cortisol makes your cat’s body less responsive to insulin which may result in diabetes.

This condition is uncommon in cats and is often caused by an adrenal gland tumor. Surgical removal of an adrenal gland tumor could be beneficial, but cats may still need insulin injections if they develop diabetes.

  • Obesity

It is common to leave food out and allow a cat to snack whenever they like throughout the day. However, you must make sure to watch your kitty’s weight very carefully. 

Annual exams to the vet would be the bare minimum to monitor your cat’s weight every year. Some cats will overeat if allowed to, especially carbohydrates-rich food, leading to obesity.

Controlling how much food your cat gets during the day and proper meal feeding is important for prevention. Your vet can help you determine how many calories your kitty needs every day.

  • Acromegaly

In extremely rare cases, the pituitary glands of your cat can produce excessive growth hormones, leading to a condition called acromegaly. This condition results in your cat’s body rejecting insulin, leading to diabetes. Unfortunately, this condition can be very difficult to manage and carries a poor long-term prognosis.

Expectations - After the Vet

Even when we know more about the disease, diabetes can be very difficult to manage. It requires a commitment to keeping a strict schedule for insulin injections, a strict diet regimen, and keeping your vet involved with your kitty’s care.

Once you find the right combination for your cat, you will be able to order the appropriate drugs and can begin to treat your cat at home. You’ll probably want to get your first supply of insulin from your veterinary clinic so that you can promptly begin treatment right away.

Unfortunately, without pet insurance, diabetes can be very expensive to manage, as in many cases, a bottle of insulin can cost a couple of hundred dollars. Your vet can also help you with some safe, yet cost-effective tips to keep a lower impact on your budget and keep your kitty well-managed.

But you may also find better prices at some of the online pharmacies. It doesn’t hurt to shop around!

Diabetes is a difficult disease but can be managed effectively when in partnership with your vet. Your vet will show you exactly how and when to administer the insulin and how to work out a schedule that fits into your lifestyle.

Generally speaking, most diabetic cats will receive two doses of insulin per day. Once in the morning and once in the evening.

Additionally, you may be able to rent or buy blood glucose monitoring equipment to test your cat’s blood sugar at home. Just like people, it is important to periodically check glucose levels to monitor the response of your cat to insulin therapy.

It may be necessary to raise or lower the dose based on the results. Again, your vet will give you guidelines on how to adjust the dose based on the numbers you are getting with your home monitoring.

If you are unable or uncomfortable with home monitoring, then you should expect to bring your cat to the vet to get its blood sugar tested somewhat frequently until your cat is stable and the disease is under control.

It can be a bit of an overwhelming experience when you start administering insulin and conducting blood glucose measurements at home. You will undoubtedly have questions pop up that you forgot to ask your vet during the visit.

With proper insulin and dietary management that most often consists of high protein and low carbohydrate canned foods, some cats can go into remission. When this happens, they will no longer require insulin but should continue on a special diet.

Cats in remission may also revert to being diabetic, so it is important to always stay in tune with any changes your cat is experiencing.

Don’t ever hesitate to call your vet if you need to double-check something or ask a question. They’re always happy to help and they understand that this can be a new and sometimes scary process!

Not all insulin are created equal! There are different types of insulin available for cats and some types may be more effective for your cat than others.

If you run out of insulin, don’t substitute it with a drug intended for people nor borrow a dose from your neighbor!

Some types of insulin come in premeasured syringes intended to administer the drug as easy as possible. Other types may come in one common vial and you would draw up the necessary dose before giving it to your cat.

Regardless, always keep your insulin refrigerated; unless you are instructed to do otherwise.

Also, pay attention to the handling instructions for the insulin given to you. For example, one type of insulin syringe is not to be shaken and must be rolled on a table prior to administering.

Don’t use a needle more than once and don’t throw away used needles in the trash. Grab an appropriate container to store needles and bring them to the vet so they can be properly disposed of.

When you first start giving insulin to your cat it may be helpful to have your spouse or friend hold your cat while you give the shot.

It may also be helpful to give an appropriate treat to your cat directly after injecting the insulin so that your cat can start to associate a treat in exchange for tolerating the shot. It’ll get used to it and you’ll become very proficient at giving shots with little experience.

Speaking of the shot, it’s nothing to be apprehensive about! It is easily administered under the skin and the needle on the syringes are so tiny that the sensation is similar to a bug bite. Again, your vet will make sure you’re comfortable giving the injection before you go home.

Ask to give a practice injection of sterile saline at the clinic so that they can watch your technique and give you any tips to make it easier for you and your cat.

The cost for insulin is not low enough to be insignificant for most budgets so cat owners should be prepared to pay roughly anywhere from $25 to $75 a month depending on the variety, dose, regimen, etc.

This is in addition to the several clinic visits you’ll need to have. This is before you establish the right protocols to keep your cat healthy and asymptomatic, though.

Remember that most cats can achieve remission after receiving insulin therapy for several months. But beware as this may be a lifelong condition and you should be prepared to make that commitment.

For the cats not able to achieve remission; the vast majority will lead to healthy and comfortable lives and be free from clinical signs when they are regularly receiving insulin therapy.

giving medicine to sick cat

A Few More Tips

When your cat urinates more frequently, it leads to accidents in the house. One thing a cat owner shouldn’t do is take away water from your pet.

Some cat parents do this because they were annoyed at coming home to find accidents in the house. This led to some trips to the emergency clinic because the owners were inadvertently causing their cats to become severely hydrated in an attempt to make up for the water deficit from peeing so much!

These signs, while not specific to diabetes, are always a response to some abnormality and warrant further investigation. It is important to note that a cat with diabetes will usually have all these signs. However, there are always rare exceptions and sometimes, a cat with diabetes may not exhibit every single one of these.

You’ll want to make sure you’re on the same schedule with other people in your home who may also be administering the drug to your cat. A simple miscommunication can lead to your cat receiving a double dose of insulin and that’s something we want to avoid.

Insulin causes blood sugar to leave the bloodstream and enter the cells. So, if we give too much insulin to a patient, we can inadvertently drop the blood sugar too low – leading to a condition called hypoglycemia.

If an additional dose is given or you gave too much insulin to your cat, call your vet right away. Be sure to know how much was given and when it was given.

If your vet’s office is not open, you should call the pet poison helpline.

You already know the signs of chronic high blood sugar, but these are the important signs to watch for if you are concerned about the possibility of hypoglycemia:

  • Disorientation. Your cat may appear stuporous or stumbly that people often say their cat is drunk when this symptom happens.
  • Weakness or an apparent lack of motor control and gait.
  • In more advanced cases cats can have seizures and even fall into a coma.
  • If you notice any of these signs, apply a small amount sugary substance (such as honey, sugar water or maple syrup) to their gums and call your vet! This can help elevate blood sugar and help to stabilize your cat until you can reach a veterinarian.

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