Acromegaly is a rare condition that results from excessive growth hormone in the body. It is usually due to a pituitary gland tumor, known as a pituitary adenoma.
Growth hormone (GH) is normally produced by the pituitary gland in the brain. Excessive amounts can result if a tumor develops in the gland.
Acromegaly affects muscle strength, bone health, and energy levels, and it can lead to unusual physical features and medical complications. It can take years for the changes to appear.
Premature death is possible, and life expectancy may be reduced by 10 years.
Three to four people in every million receive a diagnosis of acromegaly in the United States (U.S.) each year, and it affects 60 people in every million at any one time.
Fast facts about acromegaly
Acromegaly results from too much growth hormone in the body.
It can lead to unusual physical features such as swollen hands and feet, deformities, and complications, with an impact also on muscle strength and bone health.
The condition is most commonly caused by a tumor on the pituitary gland known as a pituitary adenoma.
Treatment is likely to involve a combination of surgery, radiotherapy, and medication to limit growth.
Acromegaly characteristically leads to swollen hands and large feet.
The changes brought about by acromegaly take time to develop.
Changes in physical appearance can be dramatic. They include:
a large jaw and tongue
gaps between the teeth
a more prominent brow
rough and oily skin
Other changes include:
tingling and lack of sensation in the hands and feet
a deeper voice
There may also be enlargement of the internal organs, including the heart, liver, lungs, and kidneys.
Acromegaly is very rare in children. It can lead to a condition called gigantism.
The overproduction of growth hormone that is associated with acromegaly normally results from a tumor.
The most common type of tumor is a non-cancerous, or benign, tumor in the pituitary gland, known as a pituitary adenoma.
The tumor causes the pituitary gland to produce excess growth hormone (GH), leading to abnormal growth.
Pituitary tumors are not genetically inherited from parents. They can appear randomly, due to a small genetic change of one cell within the gland.
Over time, this cell will replicate and form a tumor, called an adenoma. Adenomas are not malignant, because they do not spread to other parts of the body, but they may cause problems due to their size and location.
As the tumor grows, it can put pressure on surrounding brain tissue. Because the skull is a closed space, this growth can crowd the remaining tissue, leading to headaches and vision problems.
The location of the tumor means that the production of other hormones can also be affected.
The impact can be different for men and women, due to the type of hormone affected. Women may find that it affects their menstrual cycle, while some men experience impotence.
Around 17 percent of the population are thought to have small pituitary adenomas that do not usually produce excess growth hormone or cause any symptoms. It is only when a larger tumor occurs that the problems arise.
It is also important to note that most pituitary adenomas do not secrete any hormone. However, of the ones that do, growth hormone-secreting adenomas account for a third of cases.
In rare cases, a tumor elsewhere in the body, such as the lungs, adrenal glands, or pancreas, can lead to an overproduction of GH, resulting in symptoms of acromegaly.
This growth hormone may either be produced by the tumors themselves or because the pituitary gland is responding to a stimulus to produce GH. For example, some hypothalamic tumors may secrete growth hormone releasing hormone (GHRH), which tells the body to produce GH.
Sometimes, acromegaly is due to increased growth hormone production from outside the pituitary gland, such as from neuroendocrine tumors like small cell lung cancer or carcinoid tumors.