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.

Not too many years ago, it was believed that a diagnosis of Acromegaly was very rare when it came to cats.  Recent clinical studies at the RVC in the UK have brought to light the fact that Acromegaly is far more common than previously thought.  Dr. Stjin Neissen of the RVC Feline Diabetes Clinic is leading the charge when it comes to clinical research on the prevalence of FD and Acromegaly in cats. Further Dr. Neissen states Acromegaly (one of the endocrinopathies in the Hypersomatotropism class) is the primary cause of Feline Diabetes in more than 25% of insulin-treated diabetic cats presented for assessment of glycemic control in UK primary vet practices. No doubt as more research is conducted, the trend that 1 in 4 diabetic cats has Acromegaly will prove to be consistent globally.

Acromegaly  (pronounced ac-ro-meg-a-ly) is a medical disorder caused by a (typically benign) tumor on the pituitary gland, located at the base of the brain.  This tumor is responsible for chronic over-production of growth hormones by the pituitary gland (GH and IGF-1) and in cats is typically characterized by gradual and permanent enlargement of bones (such as the lower jaw bone), gaps between teeth, widening of the tongue, large sized paws, and unexplained weight gain (although often, Acro cats have an insatiable appetite).  In addition to the more common physical signs, high production of the growth hormone IGF-1 can cause excessive growth to internal tissues such as the throat which may result in difficulty with swallowing (likely because of an enlarged tongue) and/or breathing problems (snoring is an example).  High blood pressure is common amongst Acro cats and if the effect on the heart is severe, can result in congestive heart failure.  The growth hormone can affect the joints to the point it can make walking difficult. As well, the tumor on the pituitary gland can grow to the point it causes neurological problems.  However, not all (or any) of these symptoms may be present and even if they are, that does not necessarily confirm Acromegaly. 

One of the earliest signs of Acromegaly is a difficult to regulate diabetic cat - one that appears to be well-regulated for a time but continually goes off the rails for no discernable reason and requires increasing amounts of insulin (if not necessarily always at very high doses) to become regulated again.  If a cat with diabetes is very hard to control when it comes to regulating BG and rather than losing weight, the cat actually gains weight even when their diabetes is not well regulated; testing for Acro is something to be considered to try to detect the disease earlier rather than later. 

Acromegaly is not caused by diabetes; rather in cases of Acromegaly, diabetes is caused by the production of too much growth hormone resulting in significant decrease of insulin sensitivity.  This decreased sensitivity is due to a lack of response to circulating insulin causing the BG to rise to very high levels with the result being the development of FD.  Typically with Acro cats very large doses of insulin can be required to regulate the BG and even then, it is very common that BG never becomes "completely" well regulated putting them at greater risk to produce ketones and/or develop DKA - it is very important to check for ketone production when the diabetes is not well regulated.  The rule of thumb in the vet community is that diabetic cats requiring more than 2.0u of insulin per pound/kg are likely Acromegalic and testing to confirm is warranted.  Please note, there are many reasons why a cat might be a high dose kitty; members on forum will help you try to navigate through what's behind increased insulin needs.   

Testing for Acromegaly is not inexpensive; nor until recently has there been a definitive test that will undeniably confirm or deny a diagnosis of Acromegaly.  MRIs and CT scans can confirm or deny the presence of the pituitary tumor and are very expensive but these are not defining tests as other conditions such as Cushing's Disease present in the same manner on scans. There are a variety of blood tests to measure GH and IGF-1 hormones however these are not always accurate, especially when in the early stages of the disease. A study undertaken in 2014 by Dr. Stjin Neissen et al at the RVC determined a more inexpensive and also more accurate option available called the  IGF-1 ELISA test.  The results of Acro testing are measured in nanograms per milliliter (aka nmol/L) in most countries with the US being an exception using ng/ml.   In Europe, 1000 nmol/L or above is considered the threshold for a diagnosis of Acromegaly (100 ng/ml in the US); if test results are close to these benchmarks, the likelihood is Acromegaly.   Further information about Acromegaly testing is listed below.

Diagnosing Acro isn't always easy, nor is the treatment of Acromegaly without significant cost or commitment.  In addition to large amounts of insulin (some cats can need in excess of 150.0u of insulin daily although that is not the norm), very close monitoring of BG daily to keep close watch on BG fluctuations is required.  Expensive drugs, surgery, and radiotherapy are available options to treat, manage and/or possibly cure Acromegaly but they can literally cost many thousands of dollars.  Pasireotide significantly improves insulin sensitivity; radiotherapy treatment and surgery have cured Acro in approximately 50% of cats to the point within only a matter of days, the need for further insulin treatment subsides completely because growth hormone production is brought under control and insulin sensitivity resumes.  It is worthwhile to note, at this time data is limited when it comes to "permanent" cures for Acromegaly - as with any tumor the chance for recurrence exists - however, with the research still underway the answer as to the possibility of recurrence will come to light. 

When faced with a diagnosis of Acromegaly, considering the significant and potentially ongoing costs of all available treatment options is recommended; for example, while all options are expensive, the costs of drugs, radiation or surgery (all of which restore the ability for the body to use its own insulin) may very well prove to be less costly than the ongoing expense for insulin and test strips over a number of years. 

Not everyone can afford the cost of diagnostic testing for Acromegaly let alone the expensive treatment options available, even if they are considered a cure.  Sometimes the best we can do is only what we can -  leaving us to accept the possibility of a positive diagnosis and then do our best to prolong our cat's life with the tools we can afford.  Whether or not to pursue the various treatment options available is a very personal decision and regardless of whatever choices are made, Tight Regulation has proven time and again to be a safe and effective approach when it comes to dealing not only with Acro cats, but also those cats with other high dose requirements whether the actual cause has been confirmed or is only suspected.   Just as FD alone - while life-threatening - isn't a death sentence for our diabetic cats; well-regulated Acro cats can live a good quality of life for a number of years.  If a diagnosis of Acromegaly (or any other medical condition resulting in high insulin needs) is confirmed or simply suspected - no matter your decision when it comes to treatment options, members on forum will share their experiences and knowledge with you to help you care for your cat as best as possible.

Acromegaly In Cats

Introduction to Feline Acromegaly

Acromegaly (Hypersomatotropism) in Cats

 
DCC's Tight Regulation Approach To Acromegaly in Cats

Just as there are peer-to-peer forums available when it comes to dealing with diabetes in cats, there are internet based groups which focus on Feline Acromegaly; each with their own approaches to dealing with confirmed or suspected cases of Acro  and the diabetes that usually presents.   DCC's focus is on treating diabetes in cats using TR - Dr. Hodgkin's Tight Regulation Protocol - helping FD cat owners navigate through the various medical conditions our FD kitties are predisposed to; including Acromegaly.  We do not profess to know all there is about the disease, but what we do know is that when it comes to high dose cats, TR's very methodical approach works very well to deal with the diabetes caused by the tumor on the pituitary gland. 

While it is to be understood that anyone who is facing a diagnosis of Acromegaly will want to research the disease and work towards having their cat well-regulated with insulin; it cannot be emphasized enough how dangerous it is for any cat to receive specific dosing guidance from many different sites.  Combining of protocols is a recipe for disaster!!!!  If you are getting dosing help elsewhere and keeping a test log at TR at DCC; please disclose this fact on forum to keep your cat safe.  No one wants to be responsible for putting any cat in harms' way - Acro or otherwise. 

DCC's non-negotiable rules for testing of BG and a low carb wet diet are just as important when comes to TR for Acro cats, if not more so due to fluctuating hormone levels affecting insulin requirements.  In addition, when it comes to suspected or confirmed cases of Acro, we highly recommend frequent testing for ketones when the BG is high and if needed, the use of a basal/bolus approach (depot and fast acting insulin) in a very conservative and methodical way. ECID - every cat is different, and that saying holds very true for Acro cats as well.  Not every Acro cat will need a basal/bolus approach, or will respond the same way to depot insulin types, some will be more (or less) sensitive than others.  Changes can and may happen suddenly when it comes to insulin needs subsiding or increasing depending on the tumor's activity on any given day and is why a low carb diet coupled with close monitoring and a relatively conservative but assertive approach to figuring out the individual cats' needs and patterns will be strongly recommended. 

Experienced members on forum will help guide you through the process of regulating your Acro cat as tightly as possible.  There will be significant testing to determine as best as possible what the patterns are, and when special steps might be necessary to help regulate the BG.  As we do for most cats switching over to depot insulin types, the recommendation to obtain a prescription for fast acting insulin to have in your tool box will likely be made in the event you need it; typically the fast acting insulin is Novolog or Novorapid.   You may not need fast-acting aspart insulin, but it is far less stressful to have it on hand than it is to have to scramble to try and get some at the last minute when your cat is in crisis, producing ketones and at high risk for diabetic ketoacidosis also known as DKA.

The depot insulin Levemir seems to be a better insulin for Acro cats, likely due to its method of absorption, the flexibility it offers when it comes to dosing times, its very gentle, significantly longer curve and neutral PH.  That said, any insulin and TR will work when it comes to keeping BG under the best control possible. While a more conservative approach to what would be considered "ideal"  BG can be taken with Acro cats in consideration of fluctuating hormone levels, the goal is to get and keep the BG within safe levels reducing the risk of ketone production, DKA, further damage to internal organs and other serious health issues if at all possible.  The ultimate goal when it comes to Acro cats is to keep the BG within safe levels as best as possible and for as much and as long as possible so as not to damage internal organs or allow for further insulin resistance to occur.  At times, keeping the BG well-regulated can be a very difficult and stressful challenge when it comes to cats with Acromegaly.  It is important for care-givers to make sure the stress of dealing with an Acro cat doesn't become totally overwhelming and communicate should that happen.  Just as with all things TR, there is always a work-around.   

Excerpt of Post by Dr. Elizabeth Hodgkins - 03/10/2007

When dealing with suspected (or confirmed) Acro cats, the philosophy at DCC remains the same; "it isn't the amount of insulin that's important, if the cat needs more insulin to get the job done, doses should be increased methodically to achieve healing range.  The insulin does what the insulin does."  Just as with any other cat on TR, the approach is to systematically work with timing and amount of insulin to get to safe numbers first, and then down to numbers that will not cause damage to the pancreas or other organs.  Remember, with Acromegaly - the pancreas functions just fine - it is impaired insulin sensitivity or insulin resistance that's caused the FD.

There are many things that can be done to assist a cat with Acromegaly; a supplement regime which supports the liver, heart, mobility and overall immune system may improve quality of life. Please visit DCC's Supplement and Support Remedies sticky or post on forum for further information.  Pain medications may also be warranted, such as Gabapentin which is commonly prescribed for Acromegaly, or Buprenorphine.

DCC TR Case Study - Macchia, a Feline with Acromegaly Macchia's journey from arrival at DCC, through the Detox Process to  low carb wet food, verification of high insulin needs due to a dosing error, steps taken to achieve tightly regulated BG, confirmed diagnosis of Acromegaly  and stunning results after starting Pasireotide in August of 2015 are documented in this case study.

Beloved Acro Angel Macchia, GA 2016

  

A Message to Owners of Cats with Acromegaly

from Silva….Macchia’s Mom.

Acromegaly is a very subtle disease. An illness which, for the moment, there is no approved medicine that really works and stops its effects, I am well aware of this - in spite of the fact that I (our family) decided to give Pasireotide to Macchia. But, if we do not have the possibility of surgery treatment or a good radiotherapy, whether because this is not available in our country, or simply because we cannot afford it, we can still do a lot of good for our Acro kitties to make their life as good as possible for as long as possible.

Trying to keep the BG to safe levels by slowly adjusting the insulin doses when necessary is the best way to help them. Doing so, we protect our kitty in the best possible way. During these months at DCC, I experienced directly how efficient the TR Protocol is, regardless if our kitties are "normal" FD cats or there are some other issues behind their needs for higher doses of insulin. If I recall how high the BG levels Macchia had six, seven months ago, I am more than sure that she would not be still with us now, if I didn't meet the lovely people at DCC.

And, above all, our special fur babies need to be loved, to make them know how much they mean to us. This is the best thing we can do for our dearest special Acro kitties.

Link to Macchia's Log and TR Journey

Testing and Treatment -  Information About Acromegaly

In the UK and Europe, the RVC Feline Diabetic Remission Clinic is the leader when it comes to Acromegaly research and Treatment and has forms available for your vet to make direct contact with them for FD, Acro and Hypophysectomy - some of the RVC's clinics have ongoing clinical trials available.  Diagnostics and treatment for Acromegaly is also available at Utrecht University in the Netherlands.   

Acromegaly testing in the US is done at  Michigan State University Diagnostic Centre; Colorado State Department of Clinical Sciences, headed by Dr. Kathy Lunn is the leader in the US however, there are a number of centers nationwide from NY State, south to Florida  and west to California which provide diagnostic and treatment options for Acromegaly and other pituitary diseases. 

In Canada, the Ontario Veterinary College at the University of Guelph has diagnostic services and treatment options available, including SRT.  IGF blood tests are sent to the Michigan State University Diagnostic Centre

As information becomes available about treatment options in other countries it will be added to this document.

Acromegaly in Cats

Difficult Diabetic Cat, Could Acromegaly Be To Blame?

Hypersomatotropism, Acromegaly, Hyperadrenocorticism and Feline Diabetes Mellitus

Screening Diabetic Cats for Hypersomatotropism

Feline Acromegaly: an essential differential diagnosis for the difficult diabetic

Feline Acromegaly: The Keys to Diagnosis

Acromegaly - Rare or Rarely Diagnosed?

The Zimmer Feline Foundation - Feline Acromegaly

Evaluation and diagnostic potential of serum ghrelin in feline hypersomatotropism and diabetes mellitus

Acromegaly Treatment Options

Acromegaly Pathogenesis and Treatment (a very informative article about Acro in humans)

Feline Acromegaly: Treatment Options  

Somatostatin Agonists For Treatment of Acromegaly

Pasireotide LAR Shows Superior Efficacy for the Treatment of Acromegaly

Acromegaly Treatment and Drugs For Humans

Long-Acting Release Treatment for Feline Hypersomatotropism: A Proof of Concept Trial (Scroll down to article)

Pasireotide

Pasireotide is a relatively new drug available in the EU and NA markets approved for the treatment of Acromegaly in humans.  It comes in two forms; short and long acting, neither of which have yet been approved for use in cats. 

Clinical trials for long-lasting Pasireotide are currently underway for both feline and human use but it is not yet available on the market and is expected to be approved soon.  The RVC's Feline Diabetes Remission Clinic has recently published findings of their studies which are proving to be very encouraging when it comes to using Pasireotide. It is very important to note, neither the long or short-acting Pasireotide are guaranteed to "cure" Acromegaly, rather the purpose of Pasireotide is to greatly improve insulin sensitivity levels.  That said, many of the Acro cats in the clinical trials have gone off insulin completely. A human research study conducted  in 2013 resulted in 39% of participants having significant tumor shrinkage after three months of treatment.  

In the case of long-lasting Pasireotide, shots are given once a month with frequent monitoring and/or dosing adjustments made based on how long diabetes is well controlled.  Until long-acting Pasireotide is approved for human use and becomes available, the short-acting version of the drug is dosed BID/every 12 hours.  

 
To date, all Acro cats in the clinical trials have had marked improvement when it comes to insulin sensitivity - to the point insulin doses have been significantly reduced within a period of 24-48 hours to as little as 1.0u BID.   Clearly with such stunning and swift results, very close monitoring of BG and a very aggressive reduction to dosing scales is required, particularly during the first 3-5 days after starting Pasireotide.   Experienced members on forum can assist to navigate how quickly and how much to reduce insulin doses to prevent hypoglycemia based on glucose test results.   It is believed (but has not yet been confirmed) a reduced dose of Pasireotide might be an option to help reduce costs but still achieve good results when it comes to insulin sensitivity.

Pasireotide - An Overview of Current Mechanistic and Clinical Data (in humans)

Effects of Somatostatin Analogs on Glucose Homeostasis in Rats

Medscape(Registration required) Articles of Interest:

          -  Pasireotide for Acromegaly Study Now Published

          - FDA Approves Pasireotide for Treating Acromegaly

          - Pasireotide More Effective Than Octreotide for Acromegaly

One of the side effects of Pasireotide is diarrhea.  For some cats the diarrhea is transient and resolves quickly.  Depending on the severity of this side effect using the short-acting version of the drug makes it easier to either stop using it, or reduce the dose to minimize this issue. Most cats however are reported to still have good quality of life even with this side effect.  Prior to starting Pasireotide, it is recommended to speak with your vet about other options available to help deal with diarrhea and the potential electrolyte imbalance that could result, for example, probiotics which are suitable for diabetic cats.  Members on forum are also available to share their personal experiences when it comes to resolving diarrhea. 

Radiotherapy and Surgery

There are different types of radiotherapy as well as surgical options available for cats with Acromegaly; costs, length of treatment, requirement for and frequency of anesthesia, and expected results should all be taken into consideration and discussed in detail with your vet prior to making a decision.  Not all countries offer all options for cats although the UK, Canada, the USA and the Netherlands have most options available.

New Therapies for Pituitary Diseases - A detailed presentation about SRT by Dr. Kathy Lunn at Colorado State University.  The section on SRT on Feline Acromegaly starts on Page 10. 

Cutting Edge Brain Surgery for Felines

Hypophysectomy at the RVC

Successful treatment of acromegaly in a diabetic cat with transsphenoidal hypophysectomy Click on link for Full Text

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