Acromegaly is a condition caused by a benign tumor on the pituitary gland that results in the body's excessive production of growth hormone. Growth hormone is essential during puberty and is responsible for growth spurts. But after puberty, growth hormone production ordinarily drops to very low levels.
The condition causes abnormal growth in adults and what's called "gigantism" in children, who have not yet reached puberty, causing them to grow abnormally large.
In acromegaly, elevated growth hormone causes an abnormal increase in shoe and ring size, enlargement of the lower jaw bone and separation of teeth, and enlargement of the nose. These developments usually occur gradually and may not be noticed for years.
Other tissue in the body also can become enlarged, causing symptoms such as:
To diagnose acromegaly, a doctor measures the growth hormone level in the blood to determine if it's elevated. Because the level of growth hormone can vary widely throughout the day, the level must be measured over an extended period of time.
Doctors also may measure what's called insulin-like growth factor 1 (IGF-1), which the body produces in an attempt to suppress the growth hormone.
After acromegaly has been diagnosed by blood tests, a magnetic resonance imaging (MRI) or computed tomography (CT) scan of the pituitary is used to locate the tumor causing the overproduction of growth hormone.
The principal treatment for acromegaly is surgery to remove the pituitary tumor. Because the condition can develop very slowly, tumors are often large and can invade surrounding tissue by the time symptoms emerge. If the tumor has spread beyond the pituitary gland, radiation therapy or medication may be part of the treatment.
Medication is prescribed to reduce growth hormone levels. The drug octreotide inhibits growth hormone release. Long-term treatment can result in normal levels of growth hormone and IGF-1 in more than half of patients with the condition. Another drug, called pegvisomant, also may be prescribed.
Reviewed by health care specialists at UCSF Medical Center.