What Is Feline Acromegaly?
Feline acromegaly, also called hypersomatotropism, is a hormone disorder in which a usually benign tumor of the pituitary gland makes too much growth hormone. Excess growth hormone causes body tissues to enlarge and, most importantly, makes the body resistant to insulin. Once thought rare, acromegaly is now known to affect roughly 1 in 4 diabetic cats in some studies.
The diabetes connection
Most cats with acromegaly are first diagnosed with diabetes. If your cat needs very high insulin doses and blood sugar still stays high, ask your vet about testing for acromegaly. Learn more in feline diabetes.
Which Cats Are at Risk?
- Middle-aged to older cats, typically over 8 years
- Males more often than females
- Cats with diabetes that is hard to control
- Any breed, including domestic shorthairs
Signs to Watch For
- Increased thirst, urination and appetite (from the diabetes)
- Weight gain despite diabetes, unlike most diabetic cats who lose weight
- A broad face, larger head, enlarged paws or jutting lower jaw
- Widening gaps between teeth
- Snoring or noisy breathing from soft tissue growth in the throat
- A big belly from enlarged organs
- Stiffness or lameness from joint changes
Physical changes develop slowly and are easy to miss. Comparing old and new photos often helps owners notice them.
Diagnosis
The main screening test is a blood level of IGF-1 (insulin-like growth factor 1), which rises with excess growth hormone. The test is most reliable after a cat has been on insulin for several weeks. A CT or MRI scan confirms a pituitary tumor and helps plan treatment. Vets also check the heart and kidneys, because acromegaly can cause heart muscle thickening similar to hypertrophic cardiomyopathy and contributes to kidney disease.
Treatment Options
- Hypophysectomy: surgical removal of the pituitary tumor, available at a small number of specialty centers. Many cats go into diabetic remission afterward, but they need lifelong hormone replacement.
- Radiation therapy: shrinks the tumor and improves insulin response in many cats, though effects can take months.
- Medication: drugs such as pasireotide or cabergoline can reduce growth hormone in some cats.
- Insulin management alone: high doses of insulin, careful monitoring and a low-carbohydrate diet. This controls signs for some cats but does not treat the tumor.
Outlook
With treatment of the tumor, many cats live good-quality lives for years, and some no longer need insulin. Cats managed with insulin alone can do well for a time, but heart, kidney and neurological complications become more likely as the tumor grows.
Practical Tips for US Pet Owners
- Keep a log of insulin doses, appetite, weight and home glucose readings to share with your vet.
- Take a monthly photo of your cat’s face and paws to track changes.
- Ask for a referral to a veterinary internal medicine specialist if insulin needs keep climbing.
- Check whether your pet insurance covers advanced imaging, surgery and radiation.
When to see a vet
Call your vet if your diabetic cat needs more and more insulin, gains weight while still very thirsty, or starts snoring or breathing noisily. Seek urgent care for weakness, wobbliness or breathing trouble. Find a clinic through veterinary clinic listings.
Key Takeaways
- Acromegaly is excess growth hormone from a pituitary tumor in older cats.
- It is a leading cause of insulin-resistant diabetes in cats.
- An IGF-1 blood test is the first step; CT or MRI confirms the tumor.
- Surgery or radiation can lead to diabetic remission in many cats.
FAQ
Do dogs get acromegaly?
Rarely. In dogs it is usually caused by progesterone, either from the heat cycle or certain medications, rather than a pituitary tumor, and spaying often resolves it.
Is feline acromegaly painful?
The tumor itself is usually not painful, but joint changes and poorly controlled diabetes can cause discomfort.
Can a cat with acromegaly go into diabetic remission?
Yes. Remission is possible after successful pituitary surgery and sometimes after radiation therapy.