Acromegaly

Medical quality assurance by Dr. Albrecht Nonnenmacher, MD at April 21, 2016
StartDiseasesAcromegaly

Acromegaly is a hormonal disorder in which the body produces too much growth hormone during adulthood, leading to enlarged bones in the hands, feet, and face as well as other serious health complications. This disorder is quite rare, affecting only about three or four people out of every million. The hallmark of acromegaly is a characteristic facial appearance, including a jutting jaw, large nose, and protruding brow.

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Definition & Facts

The pituitary gland produces growth hormone throughout childhood to signal the body to develop. When growth hormone is continually produced after puberty and into adulthood, the result is acromegaly. Symptoms of this condition typically first arise in middle age. When children have an excess in growth hormone levels, gigantism is the result. The vast majority of cases of both gigantism and acromegaly are caused by a benign tumor in the pituitary gland known as a pituitary adenoma.

Symptoms & Complaints

Acromegaly manifests with a gradual enlarging of the bones, often first noticed in the hands and feet. People with this disorder will notice that their rings no longer fit and that their shoe sizes progressively increase. Gradual changes in the face are also characteristic of acromegaly, including the development of a protruding lower jaw and brow, an enlarged nose, thickened lips, and wider spacing between teeth.

Additional symptoms of acromegaly include oily, thickened, coarse skin; excessive sweating and body odor; the development of skin tags; fatigue and muscle weakness; a deepened, husky voice; severe snoring; headaches; enlarged tongue; pain and mobility issues; enlarged organs; and increased chest size.

Women with this condition may experience menstrual irregularities, while men may experience erectile dysfunction. Children who are affected by excessive growth hormone tend to grow much taller than usual, while adults experience enlarged bones and tissues but not increased stature.

Left untreated, acromegaly can lead to serious health complications. These include high blood pressure, cardiovascular disease, enlarged heart, osteoarthritis, diabetes mellitus, goiter, colorectal polyps, sleep apnea, carpal tunnel syndrome, uterine fibroids, spinal cord compression, vision loss, and early mortality.

Causes

Acromegaly stems from the overproduction of growth hormone. When this hormone is secreted into your bloodstream, the liver is triggered to produce insulin-like growth factor 1 (IGF-I), which in turn stimulates the abnormal growth of bones, tissues, and organs. The excess in growth hormone is usually caused by a noncancerous tumor of the pituitary gland. In some instances, acromegaly can also be triggered by a tumor in the lungs, pancreas, or adrenal glands.

Diagnosis & Tests

Because the changes associated with acromegaly occur gradually and because the condition is so rare, a diagnosis is often not made until the condition has been progressing for several years. But because early diagnosis is so important for prognosis with this condition, it is important for patients to speak with their doctors right away if they notice symptoms.

If the doctor suspects acromegaly after a physical examination, blood tests will be conducted to check for abnormal levels of growth hormone and IGF-I. If these levels are elevated, definitive diagnosis will be made using a growth hormone suppression test, in which lab values are tested before and after ingestion of a glucose preparation. Additionally, imaging tests such as MRIs can be done to monitor the size and location of a pituitary tumor.

Treatment & Therapy

Treatment focuses on reducing and hopefully eliminating the tumor's effects on the pituitary gland and related systems in order to resolve symptoms. In many cases, the doctor will remove the tumor through the nose in a procedure called transsphenoidal surgery. Removal eliminates the pressure on the pituitary gland, restoring normal function.

In some cases, only part of the tumor can be successfully removed, requiring medication and/or radiation treatments to alleviate remaining symptoms. Medications that are effective for treating acromegaly include synthetic versions of the hormone, somatostatin, which works to lower growth hormone levels; dopamine antagonists, which can lower growth hormone and IGF-I levels as well as shrink the pituitary tumor; and growth hormone antagonists, which block the effects of the hormone on body tissues.

For some people with acromegaly, radiation therapy is necessary to reduce the size of the tumor and lower abnormal hormone levels. This may consist of conventional radiation therapy, which is given five days a week for four to six weeks; proton beam therapy, which provides a targeted dose of radiation directly to the tumor site; and stereotactic radiosurgery, which can often reduce the size of the tumor with a single dose.

In many cases, it takes between 10 and 20 years and a combination of treatment modalities to help bring the hormone elevations to an acceptable level. For this reason, people with acromegaly will have the best results when they are treated by a team of specialists led by an endocrinologist with a profound understanding of this condition.

If the pituitary tumor cannot be completely removed, lifelong management and medication regimens may be required to prevent complications and prolong lifespan. Patients should be monitored for changes in features, change in tumor size, changes in hormone levels, and the presence of elevated pituitary hormones beyond growth hormone and IGF-I levels.

Prevention & Prophylaxis

While there is no way to prevent the development of acromegaly, being aware of the symptoms can lead to prompt diagnosis and treatment. Women who have been diagnosed with acromegaly may be unable to carry a pregnancy to term, so it is important for women with this condition who are interested in becoming a mother to consult with their endocrinologist to learn more about their options.

The National Institutes of Health maintains a database of clinical trials for new methods of treatment for acromegaly. Those who have this condition who are not responding to treatment may be a candidate for a clinical trial. It is important to talk with one's doctor to find out which experimental treatments may be safe and effective.