Acromegaly is a hormonal disorder that results from too much growth hormone (GH) in the body. The pituitary, a small gland in the brain, makes GH. In acromegaly, the pituitary produces excessive amounts of GH. Usually the excess GH comes from benign, or noncancerous, tumors on the pituitary. These benign tumors are called adenomas.
Acromegaly is most often diagnosed in middle-aged adults, although symptoms can appear at any age. Scientists estimate that three to four out of every million people develop acromegaly each year and about 60 out of every million people suffer from the disease at any time. Because the clinical diagnosis of acromegaly is often missed, these numbers probably underestimate the frequency of the disease.
If not treated, acromegaly can result in serious illness and premature death. Acromegaly is treatable in most patients, but because of its slow and often “sneaky” onset, it often is not diagnosed early or correctly. The most serious health consequences of acromegaly are:
- Type 2 diabetes
- High blood pressure
- Increased risk of cardiovascular disease
- Increased risk for colon polyps, which may develop into colon cancer if not removed
When GH-producing tumors occur in childhood, the disease that results is called gigantism rather than acromegaly. A child’s height is determined by the length of the so-called long bones in the legs. In response to GH, these bones grow in length at the growth plates—areas near either end of the bone. Growth plates fuse after puberty, so the excessive GH production in adults does not result in increased height. However, prolonged exposure to excess GH before the growth plates fuse causes increased growth of the long bones and thus increased height. Pediatricians may become concerned about this possibility if a child’s growth rate suddenly and markedly increases beyond what would be predicted by previous growth and how tall the child’s parents are.
The most common symptoms of acromegaly are the abnormal growth of the hands and feet. Swelling of the hands and feet is often an early feature, with patients noticing a change in ring or shoe size, particularly shoe width. Gradually, bone changes alter the patient’s facial features: The brow and lower jaw protrude, the nasal bone enlarges, and the teeth space out.
Overgrowth of bone and cartilage often leads to arthritis. When tissue thickens, it may trap nerves, causing carpal tunnel syndrome, which results in numbness and weakness of the hands. Body organs, including the heart, may enlarge.
Other symptoms of acromegaly include:
- Joint aches
- Thick, coarse, oily skin
- Skin tags
- Enlarged lips, nose, and tongue
- Deepening of the voice due to enlarged sinuses and vocal cords
- Sleep apnea — breaks in breathing during sleep due to obstruction of the airway
- Excessive sweating and skin odor
- Fatigue and weakness
- Impaired vision
- Abnormalities of the menstrual cycle and sometimes breast discharge in women
- Erectile dysfunction in men
- Decreased libido
In more than 95 percent of people with acromegaly, a benign tumor of the pituitary gland, called an adenoma, produces excess GH. Most pituitary tumors develop spontaneously and are not genetically inherited.
Rarely, acromegaly is caused not by pituitary tumors but by tumors of the pancreas, lungs, and other parts of the brain. These tumors also lead to excess GH, either because they produce GH themselves or, more frequently, because they produce GHRH, the hormone that stimulates the pituitary to make GH. When these non-pituitary tumors are surgically removed, GH levels fall and the symptoms of acromegaly improve.
No single treatment is effective for all patients. Treatment should be individualized, and often combined, depending on patient characteristics such as age and tumor size. Currently, treatment options include surgical removal of the tumor, medical therapy, and radiation therapy of the pituitary. Goals of treatment are to:
- Reduce excess hormone production to normal levels
- Relieve the pressure that the growing pituitary tumor may be exerting on the surrounding brain areas
- Preserve normal pituitary function or treat hormone deficiencies
- Improve the symptoms of acromegaly
Even when surgery is successful and hormone levels return to normal, people with acromegaly must be carefully monitored for years for possible recurrence of the disease. More commonly, hormone levels improve, but do not return to normal. Additional treatment, usually medications, may be required.