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Understanding the Disease

Acromegaly

What is Acromegaly?

Acromegaly is a rare disease. In fact, it's not known exactly how many people in the United States have it. Worldwide, it's believed that 60 out of every million people are affected by acromegaly. Yet, recent studies suggest the numbers might be as high as 115 to 295 out of every million people. The term "acromegaly" comes from the Greek words "acro" (extremities) and "megaly" (enlargement). As the name suggests, acromegaly can be recognized by abnormal growth of the hands and feet, as well as other signs such as enlargement of the facial features. However, acromegaly also involves changes in the way the body functions. Over time these changes can cause serious complications. These health risks make it important to attain and maintain control of the condition once it has been diagnosed. 

What Causes Acromegaly?

Acromegaly is caused by the uncontrolled hypersecretion of growth hormone (GH) by the pituitary, a tiny gland — about the size of a pea — located just below your brain, behind your eyes. The pituitary is also known as the "master gland" — this is because it controls multiple functions, including normal growth, metabolism and reproductive activity. In most cases, the cause of this excessive production of GH is a noncancerous tumor on the pituitary. This pituitary tumor secretes a high level of GH, causing the enlargement of many body parts, such as the hands and feet. Because of where it is located, this tumor can also cause headaches with pressure behind the eyes.

There are 3 important hormones that circulate throughout your body that regulate many of the most basic activities of your body. These hormones play a key role in acromegaly:

Growth Hormone (GH) - The pituitary releases GH in short spurts throughout the day and night, resulting in constantly varying GH levels. When a person has acromegaly, abnormally high levels of GH are released by the pituitary. Too much GH causes changes in physical characteristics and other aspects of your body.

Insulin-like Growth Factor-1 (IGF-1) - IGF-1 levels rise whenever GH levels rise; however, IGF-1 (made mostly in the liver) is released more evenly than GH, and IGF-1 levels remain higher longer. When both of these levels are elevated together, they can also cause many of the signs and symptoms of acromegaly.

Somatostatin - One of the main effects of somatostatin is its ability to control the amount of GH in the body. Researchers have taken advantage of this knowledge in developing treatments for acromegaly.

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