Insulin Resistance, Diabetic Cat Care

The information contained in this sticky is provided for educational purposes only and is not intended to replace veterinary advice. The intention of this sticky is to open doors to understanding about the specific medical condition or topic, allowing for educated and on-going discussion with your vet.

Chirpie Angel, GA

Diabetic Cat Care

Insulin Resistance

Each of us wants nothing more than for our FD cats to start TR, quickly become very well-regulated, spending most of the time in healing numbers and end up going OTJ as quickly as possible. Unfortunately, that isn't always what happens; sometimes our cats just don't respond the way we expect or hope they will.

Lack of response to the insulin can be the result of undiagnosed FD lurking in the background for years, taking its toll on the beta cells and pancreas. In other cases the use of steroids, the need for dental cleanings, Pancreatitis, Hyperthyroidism, urinary infections and other health issues can result in insulin resistance which can be temporary for some cats. Others might not be so lucky as in some cases there are very specific diseases which are behind insulin resistance, for example; Acromegaly, Insulin Auto Antibody (IAA) and Cushing's Disease. When insulin resistant - whether the resistance is temporary or permanent, the need for significantly larger doses of insulin is normally required to regulate the BG.

In 2010, Dr. Thomas A. Graves, DVM, MS, PhD, Dipl ACVIM, Illinois, USA wrote a paper addressing the topic of Insulin Resistance in Cats;

The term “insulin resistance” is used differently in human and veterinary medicine. In terms of pathophysiology, insulin resistance is defined as peripheral antagonism to insulin. If target tissues cannot respond to insulin secreted by the pancreatic beta cells, diabetes ensues. Insulin resistance can be due to degradation of insulin, insulin receptor defects, post-receptor defects, or glucose transport defects. In veterinary medicine, we use the term insulin resistance to describe persistent hyperglycemia in the face of insulin dosages in excess of 2 to 2.5 units/kg. This may or may not reflect true insulin resistance at the cellular level.

It should be noted that “apparent” insulin resistance is probably the most common form of the condition. Things that mimic insulin resistance include inappropriate handling and storage of insulin, improper administration of insulin, improper care and feeding, use of the wrong type of insulin, or insulin-induced hyperglycemia.

Dr. Graves' full article about insulin resistance

When a cat is not responding to insulin as expected, a process of elimination will begin in an attempt to determine if there might be something the owner is inadvertently doing which is perpetuating the appearance of insulin resistance. This will include requesting BG curves be done to confirm or deny if the current dose of insulin might be too high causing unknown lows that result in chronic rebound, perhaps giving more time between shots to see if too much overlap might be an issue, and/or to determine if how quickly the individual cat utilizes the insulin might have changed. In addition, reviewing when the vial of insulin was opened and how it is handled or stored, how shots are drawn and administered, feeding, what medications or supplements might be affecting the BG, looking at previous blood work for clues, and other things which might be playing a role. When the review reveals no identifiable cause for the lack of response to the insulin, then further specific blood testing at the vet's will be recommended to determine if there is a particular health issue responsible.

Should your cat turn out to be insulin resistant, it is important to note it is not the amount of insulin being administered that is important, it is what the amount of insulin does. The goal when insulin resistance presents is to try to regulate the BG as best as possible, as quickly as possible, specifically to avoid secondary health issues from developing (ketones, UTI's, etc.).

When working with high dose cats, it may be recommended to use a "basal/bolus" approach; which means using two insulin types. Basal is the long lasting (background) insulin/bolus is the short or fast acting insulin used to deal with things like food spikes. Please note, there are different types of fast acting insulin and it is VERY important to understand the specific method of action for each type available. Please post on forum for individual assistance from highly experienced members when it comes to using a Basal/Bolus approach for high dose cats.

No matter the cause for insulin resistance, it is very important the cat is being fed a low carb diet, particularly as there may be times when whatever is causing the resistance to insulin can subside quite suddenly, dropping the cat very low completely unexpectedly as might be the case with IAA for example. While the risk of hypo is potentially heightened with insulin resistance due to the significantly higher doses (and the possible use of bolus insulin); depending on the circumstances, a low carb diet will provide as much safety as possible which is explained in the sticky, the liver's job. For cats displaying insulin resistance, it is recommended to keep some higher carb food on hand in the event of a sudden, or extended low - this is the preferred method rather than using syrups if at all possible. However, it is important to note, when it comes to high dose cats (particularly those with IAA), because of the significantly higher amounts of insulin being used, syrups might be needed if the BG drops extremely low very suddenly.

When it comes to detoxing a high dose cat from high carb food, it is not recommended to withhold insulin completely for 24 hours. Rather, insulin doses would be lowered and insulin would continue with the bg monitored very closely while high carb foods are moving out of the system. Typically if ketones are not being produced, insulin doses might be reduced by half, and the time period for detox might be shortened to as little as even +12 hours - but more likely +18 hours - depending on test results, ECID. Once it is clear how much the BG might be affected by the reduction of Dry Matter Carbs, increases start to resume to determine if (and by how much) insulin needs will be lessened by the change to low carb wet food. This is one of those ECID (Every Cat Is Different) situations and it is highly recommended that anyone with a High Dose Kitty seek out guidance from experienced members on forum as to how to handle the Detox Process for their cat as safely as possible before switching to low carb wet food.

Typically high dose kitties are very hungry (usually because its so hard to keep their BG well-regulated), and they can require a lot more food than the standard recommendation of 6-8 ounces per day. Generally this ravenous hunger occurs because the resistance to the insulin doesn't allow for the nutrients from their food to be absorbed by their bodies just as it does for normal FD cats. It's a catch twenty two; the increased food intake affects the BG, the stress from being hungry also affects the BG which results in more insulin being required for the cat to become well-regulated. In such cases, it is recommended to track food intake every day so it is known how much food is being fed. If it is at all possible, try to keep to about 10 ounces of food per day maximum, otherwise it will be necessary to continue to increase insulin until there's enough on board to deal with the amount of food and then do the job of regulating the BG as best as possible.

Acromegaly 101

In recent years studies completed at the RVC in the UK have proved that Acromegaly is far more common than has been believed. Acromegaly is the result pituitary tumor which causes an increased secretion of Growth Hormone (GH) which in turn, results in the liver producing Insulin Like Growth Factor (IGF-1). Increased production of both these hormones result in insulin resistance. While the pancreases and/or pancreatic beta cells of Acro cats are not damaged as they are with Feline Diabetics, the cells are not able to utilize the insulin the pancreas produces. The medical term for Acromegaly ishypersomatotropism. For more detailed information about Acromegaly, please visit DCC's Acromegaly sticky.

IAA - Insulin Auto Antibodies

Anytime we inject something into our bodies, our systems naturally identify whatever it is as a "foreign substance". In the case of IAA, it is the body responding to insulin as that foreign stubstance. With the introduction of many different types of insulin, based on animal or synthetic materials, it is becoming slightly more common for some cats to be diagnosed with IAA - Insulin Auto Antibodies. Typically when IAA occurs, large amounts of insulin are required to gain control over the BG, however the body's natural response is to fight the increased insulin. In most cases, it is reported that with very aggressive insulin administration it is likely that IAA resistance to insulin can eventually be overcome, insulin doses generally can be lessened, and even diet controlled diabetic remission can occur. In the case of IAA, it is very important that a low carb diet is being fed as the insulin resistance can resolve quite suddenly with the cat dropping very low. For more information about IAA click here.

Cushing's / Addison's Disease

Cushing's disease is the result of over-production of adrenal gland hormones where Addison's disease is the opposite, a lack of production of adrenal gland hormones. Adrenal disease is not very common in cats but it does occur more often as Cushing's disease. Typically the signs of adrenal disease are a pot belly and thin skin which may tear very easily. Insulin resistance is a very common occurrence when it comes to both Cushing's and Addison's disease. Specifically, it is the level of cortisol in the body which is behind the insulin resistance. Prolonged and over-use of steroids can lead to the adrenal disease Hyperadrenocorticism in cats.

If your cat seems to require high doses of insulin, please don't despair. Take a big breath, come post on the Talking TR forum - tell us about your cat, when and how it was diagnosed, what other health issues might be in play, what the dosing history has been so far. Most cats on large doses of insulin aren't actually High Dose Kitties. Often (and usually pretty quickly) the cats start doing really well once TR is started. If it turns out your cat is in fact Insulin Resistant - even then, it doesn't usually take very long to figure out what tweaks the cat needs to turn them around. Quite honestly, there are very few high dose cats experienced members at DCC haven't been able to turn into very well-regulated kitties!

Test Log Examples of once Insulin Resistant Cats, well-regulated on TR at DCC:

Mischa Insulin Resistant, unknown cause

Macchia GA, Acromegaly

Chirpie GA, CRD

Sammi Arrived at DCC on 5.0u of insulin BID, immediately well-regulated on the SS (0.25u first rung) with diet change - not insulin resistant after all!

Quite the opposite in fact!