My Cat’s Experience With Feline Acromegaly

Caitlin Dempsey


A black cat with a cone and a bandage around her front right leg.

A subtle clue that something was going on with my cat Lulu started over a year ago when she began caterwauling shortly after we went to bed. This sudden change in behavior was out of character for my cat who would usually be found in bed snoozing away.

Shortly after the nightly caterwauling started, my cat also began to beg for food. Incessantly. For the first eight years of her life, my cat was super picky. Lulu never ate the same type of cat food twice in a row. I used to jokingly call her my hummingbird cat because she would eat a couple of bites, walk away, come back again maybe 15-30 minutes later, eat another few bites. Rinse and repeat.

She flipped from barely eating to constantly wanting to eat. No longer picky, Lulu would race through her meals and sit on the kitchen counter, loudly begging for more. She started steamrolling the other two cats, literally hitting them from behind with her head to push them out of the way so she could eat their meals as well. I started having to stand there at breakfast and dinner time, monitoring the cats so the other two could eat in peace.

A black cat lying next to an empty white cat food dish on top of a dark wooden table.
My cat would spend hours waiting by her empty food dish, hoping for more. Photo: Caitlin Dempsey.

Shortly after her nonstop hunger started, I took her to our vet – I was sure she had something medical happening. Yet the vet ran a blood panel and called to tell me “all the test results are normal, it’s in her head.” But I knew something was wrong so I kept monitoring her.

The incessant cries for food continued – she would park herself in the kitchen, howling loudly whenever anyone came in. Then one day a couple of months later, I noticed her straining over and again, trying to pee. “Uh oh,” I thought. She must have a urinary tract infection.

So, back to the vet she went. And sure enough, her urine panel came back positive for a UTI. What the vet also noticed was elevated sugar levels in her urine. Another blood panel confirmed elevated glucose.

Now diagnosed with probable diabetes, our cat was started on twice daily insulin shots and prescribed pet food that is ultra low in carbs. The insulin they prescribed was Glargine which we had to pick up from a human pharmacy.

Glargine is a popular choice of insulin for cats because it is longer acting and has been shown in the research that, when combined with a low-carb diet, results in total remission of diabetes in most cats.

The vet started out our cat with 0.5 units, the standard starting point for cats. She went for twice weekly blood draws to test her glucose levels. Yet her blood sugar continued to remain high. Each week the vet would bump up her insulin amount and numerous tests were run to rule out any possible illness that might be interfering with her insulin response. After a few months and reaching the upper limits of insulin at 5 units, he recommended that we consult with an internist to figure out why her diabetes was not able to be controlled.

A cropped picture of a prescription for insulin for a cat.
Insulin prescribed for a cat. Parts of the prescription label have been blurred for privacy. Photo: Caitlin Dempsey.

Fortunately, we live near an animal hospital with specialists on staff and we booked a consult with an internist veterinarian. The vet ran a bunch of tests, all coming back normal. She called me and said, “well, there is a specialist testing center in Chicago that I want to run one last test. Only a small number of cats with uncontrolled diabetes mellitus have this ailment but I want to test for it.” After I hung up, I turned to my husband and said,”with our cat’s history, I just know this test is going to come back positive.”

Sure enough, a few days later, the vet called to let us know that the test came back indicating our cat most likely had feline acromegaly. A consult with Dr. Google confirmed that our cat had a lot of the symptoms for this disease. Uncontrolled diabetes with accompanying weight gain instead of weight loss, a widening of her face — these classic symptoms were ones my cat had.

What is feline acromegaly?

Feline acromegaly was first described in 1976 by Gembardt and Loppnow. Feline acromegaly is a relatively rare endocrine disorder in cats and is caused when a tumor presses on the pituitary gland located in the cat’s brain. This pressure triggers the overproduction of the growth hormone somatotropin.

The word acromegaly comes from the Greek word akron  meaning “extreme” or “extremity” and megas  meaning “large”.

The excessive hormone levels lead to abnormal growth, enlarging of the facial features and paws, and enlargement of various tissues and organs, such as the heart, kidneys, and bones. It’s also what causes uncontrolled diabetes and left untreated can lead to heart congestion from an enlarged heart, kidney failure, and ultimately death.

What causes a cat to develop feline acromegaly?

No one is really sure what drives some cats to develop the tumor that results in feline acromegaly.

My cat has certainly been prone to health issues. Lulu was the runt of a litter with five male kittens and was easily outmatched in the competition for her mother’s milk. When we adopted her from a local rescue, her fosterer told us how she had spent countless sleepless nights nursing her as a very young kitten from near death.

A few days after we brought her home, she developed idiopathic vestibular syndrome, wobbly around in circles in the bathroom. She recovered from that initial illness but was left with a permanent head tilt.

A black cat sitting in a planter with green grass against a brick wall.
Lulu’s head tilt was a permanent effect from having vestibular syndrome. Photo: Caitlin Dempsey.

When she was about six years old, she came down with a fever and wouldn’t eat food for a week. Multiple very expensive diagnostics later, she was diagnosed with a Bartonella infection, known as “cat scratch fever”. It’s a bacterial infection cats can pick up from ingesting flea poop. Fortunately a round of antibiotics resolved that very quickly.

Given her history, I did ask the internist if any of her prior illnesses could have factored into her developing feline acromegaly and her reply was a simple, “maybe.”

The studies on what kind of cats develop feline acromegaly and why are very limited. One study of 14 cats found it presented in mostly older male cats with an average age of 10.2 years. Lulu, at almost eight years of age when she was diagnosed, is considered to be fairly young to have developed feline acromegaly. And of course, she is a female cat.

That said, her age gave her a good chance of survival and quality of life if she were to receive the recommended treatment for feline acromegaly. Cats left untreated tend to only live about 18 months post diagnosis as heart failure will cause death.

Treatment for feline acromegaly

Brain surgery is a common treatment when humans are diagnosed with acromegaly. For cats, there are very few facilities in the world that offer this and it’s a very expensive option. More commonly, target radiation, known as stereotactic radiation therapy (SRT), is the course of treatment.

How expensive is it to treat a cat that has feline acromegaly?

Treating a cat for feline acromegaly is pretty expensive, especially if you don’t carry pet insurance. The costs for treating feline acromegaly vary depending on how many rounds of radiation are needed.

Without pet insurance, costs for the complete course of treatment (not including the monthly insulin costs) can run well into $20,000 even if you only need a few rounds of radiation.

A picture from a CT scan of a tumor on a cat's pituitary gland.
The imaged picture from Lulu’s SRT treatment plan showing the tumor on her pituitary gland.

Why is a CT scan need to diagnose feline acromegaly?

Part of the expenses is the costly CT scan which does two things. First, it confirms the presence of a tumor.  The serum growth factor (IGF-1) measurement will only tell the vet that your cat has a higher than normal level of growth hormone, not the actual cause.

Second, the CT scan maps out the location and size of the tumor. This information is used by the radiologist to precisely map out where the radiation will be directed into the cat’s brain to target only the tumor.

Your cat will need to be anesthetized during the CT scan and radiation treatments

In addition, you also have to pay for your cat to be anesthetized for both the CT scan and the radiation treatment as your cat will need to be completely immobilized. A custom made immobilizer will be created to hold your cat during all treatments.

Number of radiation treatments for feline acromegaly

Radiation costs will depend on the number of treatments. The radiologist will come up with a radiation treatment plan including the number of sessions that depends on the size of the tumor. The higher the number of radiation sessions, the higher the cost of the treatment for feline acromegaly.

Since Lulu had been diagnosed very early, the radiologist determined she would need three rounds of radiation to treat her tumor. A special mold was custom created for Lulu to hold her during her treatments and she put under anesthesia for each session in order to keep her still.

The treatments were done over three consecutive days. Each morning she was dropped off after fasting all night. In the afternoon, I would pick her up. The port for her anesthesia was left in and she had to wear a cone to prevent her from picking at the bandage for it.

A black cat with a cone and a bandage around her front right leg.
Lulu would come home at the end of every day while she was getting her targeted radiation treatment. Photo: Caitlin Dempsey.

Post SRT treatment for feline acromegaly

Post-SRT treatment recovery usually takes about nine months.

The most immediate effect of the treatment was her voice. For about a week after the third and final radiation treatment, Lulu’s cries were really deep. She normally has a pretty high-pitched meow. She was a little tired on the first day post treatment but didn’t seem to have the crash in energy that the radiologist warned might happen.

The internist took over her post-SRT treatment recovery and Lulu had to come in about six weeks after her radiation treatments for a fructosamine which can provide the average blood glucose levels of a cat over the course of about two weeks. The internist was please with her response and started to lower the number of units. Over the course of several months she gradually dropped from 5 to 4 then 3 units.

Lulu, for now, has settled on needing 2.5 units of insulin. Both the radiologist and the internist have felt that Lulu would always need insulin. This is in line with one study from 2018 that looked at post SRT diabetic response in 41 cats and found that 95% of treated cats had their subsequent insulin dosage reduced and 32% of those cats eventually went in to full remission of their diabetes.

Lasting effects of feline acromegaly

A lot of the physical changes that happen as a result of growth hormone being pumped out by the tumor are permanent. Lulu grew from a small-sized cat to a medium sized cat. She used to be the same heigh from paw to shoulder of our male orange tabby, who was also a runt. Now she is a good 1 1/2 inches higher than him.

Fortunately, tests indicate that her heart and other internal organs appear to be normal and unaffected.

Her fur, which was already a medium length and full, is now very thick. As her recovery from her radiation treatment has progressed, it has thinned out somewhat but it’s still thicker than it was before.

A side by side comparison with a black cat with white fur on her chest and the same cat with feline acromegaly with no white fur on her chest.
A six years old, my black cat had a generous sprinkling of white fur on her chest (left photo). At eight years old and afflicted with feline acromegaly, all but a few sparse white hairs remained. Overall, her fur is much thicker now. Photos: Caitlin Dempsey.

All of the white hair that had been continuously popping up on her chest is now completely gone and her fur is now entirely black.

Lulu continues to be monitored by the internist. It’s been about seven months since Lulu got her radiation treatments. She still has about two more months to reach the nine-month milestone where most cats realize their full recovery potential. She has another checkup at the end of this month and I am hoping her internist lowers her insulin dose again.

A black cat lying on a black bag on a wooden floor in front of a bookcase with a cat tree in the background.
Lulu still enjoying her favorite pastime, lying on black things. Photo: Caitlin Dempsey.

She does seem to have some neuropathy that has presented from the lingering diabetes. Her legs flail out when she runs and she twitches when you touch the middle of her back. She is still food focused although not as urgently as she was before her radiation.

Her energy levels haven’t rebounded to what they were before she got sick but she does show more interest in doing things like hanging out in the catio for some sun and bird watching.


Gembardt, C., & Loppnow, H. (1976). Zur Pathogenese des spontanen Diabetes mellitus der Katze. II. Mitteilung: Azidophile Adenome des Hypophysenvorderlappens und Diabetes mellitus in zwei Fällen. Berl Munch Tierarztl Wochenschr89(17), 336-340.

Marshall, R. D., Rand, J. S., & Morton, J. M. (2009). Treatment of newly diagnosed diabetic cats with glargine insulin improves glycaemic control and results in higher probability of remission than protamine zinc and lente insulins. Journal of feline medicine and surgery11(8), 683-691. DOI: 10.1016/j.jfms.2009.05.016

Peterson, M. E., Taylor, R. S., Greco, D. S., Nelson, R. W., Randolph, J. F., Foodman, M. S., … & Lothrop, C. D. (1990). Acromegaly in 14 cats. Journal of Veterinary Internal Medicine4(4), 192-201.

Wormhoudt, T. L., Boss, M. K., Lunn, K., Griffin, L., Leary, D., Dowers, K., … & LaRue, S. M. (2018). Stereotactic radiation therapy for the treatment of functional pituitary adenomas associated with feline acromegaly. Journal of veterinary internal medicine32(4), 1383-1391. doi: 10.1111/jvim.15212

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About the author
Caitlin Dempsey
Caitlin Dempsey holds both a master's in Geography from UCLA and a Master of Library and Information Science. She is the editor of and an avid researcher of geography and feline topics. A lifelong cat owner, Caitlin currently has three rescued cats: an orange tabby, a gray tabby, and a black cat.