Acromegaly is a medical condition in cats and dogs that results from the overproduction of growth hormone. Because increased growth hormone promotes excessive bone, soft tissue, and cartilage growth, patients with acromegaly will often have an increased body size, enlarged head, and organs that are larger than normal. A long jaw, large paws, and increased space between the teeth are also quite common in pets with acromegaly.
In dogs, the cause of acromegaly is most often excess progesterone exposure, either from the administration of medications to alter the heat cycle or from the natural production of progesterone during hormonal cycling in older intact female dogs.
In cats, however, the cause of acromegaly is almost always a benign pituitary tumor that results in excess growth hormone production. Because growth hormone also happens to have an anti-insulin affect, cats with acromegaly are often diabetic.
Definitively diagnosing acromegaly can pose a challenge. Of course, the distorted physical appearance of the affected animal can give a nudge in the right direction, but from there it can be difficult. There are currently no commercially-available tests for growth hormone levels in pets, though a blood test that measures insulin-like growth factor can be used to aid in the diagnosis of acromegaly.
In patients where the underlying cause of increased growth hormone is a pituitary tumor, imaging of the brain by either an MRI or CT scan will show this. Cats who have insulin-resistant diabetes should be further evaluated for acromegaly, especially if they have alterations in their appearances.
For the treatment of acromegaly in dogs, removal of any progesterone treatments should be curative and intact dogs should be spayed or neutered. Unfortunately, there is currently no good treatment for cats with acromegaly, as the removal of pituitary tumors is not yet practical.
Cats with acromegaly are at risk of developing cardiomyopathy due to an enlarged heart, kidney disease due to enlarged kidneys, and overtime a growing pituitary tumor could cause neurologic signs. Cats with acromegaly will often eventually be euthanized or die from heart disease, kidney disease, neurologic disease, or uncontrolled diabetes.