What Is Acromegaly? What Causes Acromegaly?

Editor's Choice
Main Category: Endocrinology
Also Included In: Neurology / Neuroscience
Article Date: 09 Jun 2011 - 0:00 PST


Acromegaly is a syndrome that is brought about by the pituitary gland producing too much growth hormone after puberty. In most cases it is the result of a tumor developing within the gland. The changes caused by this growth hormone excess are not noticeable straight away, but will vastly change the person's appearance after a number of years.

If left untreated, acromegaly can lead to a number of medical complications and premature death, not to mention the continuation of visual disfigurement. Acromegaly is a rare condition and affects less than one hundredth of a percent of people in the US. The name comes from greek acro which means extremities and megaly which means enlargement.

According to Medilexicon's medical dictionary acromegaly is:

"A disorder marked by progressive enlargement of peripheral parts of the body, especially the head, face, hands, and feet, resulting from excessive secretion of somatotropin; organomegaly and metabolic disorders occur; diabetes mellitus may develop."

What are the signs and symptoms of acromegaly?

A person suffering acromegaly will experience a change in their physical appearance and other characteristics. These may include:

• a large jaw
• gaps between the teeth
• a more prominent brow
• the soft spot of their skull appears expanded
• hands shaped like spades
• a lack of sensation and tingling in hands and feet
• rough and oily skin
• skin tags
• heavy sweating
• headaches
• large tongue
• deeper voice
• impaired vision
• large feet
• swelling of internal organs (particularly the heart)

These changes happen over a number of years, so they might not be noticeable straight away. Someone that has not seen the person with the condition for a while may notice a big change in their appearance.

What causes acromegaly?

There are a few possible causes of acromegaly. The most common cause is the growth of a non-cancerous (benign) tumor in the pituitary gland (known as pituitary adenoma). This causes the pituitary gland to produce excess GH (growth hormone) which is the reason for abnormal growth. Pituitary tumors are not inherited in a person's genes and can appear randomly due to a small genetic change of one cell within the gland.

As the tumor grows, it can put pressure on surrounding brain tissue, causing the tissue to condense. This can result in headaches and can affect the person's vision. Due to the location of the tumor, production of other hormones can also be affected. This can differ for men and women, due to hormone type. For example, in women it may affect their menstruation cycle, where-as men may suffer with impotence.

In some cases, acromegaly has been the result of a tumor located elsewhere in the body, such as the lungs, adrenal glands and the pancreas. Again, these tumors result in overproduction of GH, either produced by the tumors themselves or by the pituitary gland. The pituitary gland produces GH due to the tumors producing 'growth hormone releasing hormone' (GHRH). When acromegaly has been the result of a tumor outside the pituitary gland, the gland may still swell and can be confused for a tumor.

What are the complications of acromegaly?

If not treated, acromegaly can have major detrimental affects on a person's health and can result in premature death. Acromegaly sufferers can develop the following:

• Arthritis
• Cardiomyopathy (type of heart disease)
• Carpal tunnel syndrome
• Compression of the spinal cord
• Diabetes
• Hypertension (high blood pressure)
• Hypopituitarism (lower production of other pituitary hormones)
• Kidney failure
• Loss of vision
• Polyps (precancerous growths) within the colon
• Sleep apnea
• Uterine fibroids

How is acromegaly diagnosed?

To test for acromegaly, a doctor would usually perform a combination of the methods listed below:

• Take the person's IGF-1 level - someone with acromegaly will usually have a high level of IGF-1; another type of growth hormone. This is because GH can stimulate the production of IGF-1 within the liver. The levels of other pituitary hormones (such as ACTH, TSH, FSH and LH) can also be taken.
• OGTT (oral glucose tolerance test) - in order to get a more accurate reading of GH a doctor may recommend this test. The patient would need to fast overnight and have a sample of their blood taken in the morning before and after drinking some concentrated glucose solution. Usually the ingestion of glucose would lead to a fall in hormone levels, however the levels would be high if the body is producing excess GH.
• MRI (magnetic resonance imaging) - an MRI scan would be carried out on the brain to determine the location and size of the tumor.

What are the treatment options for acromegaly?

There are a few ways of treating acromegaly. The appropriate method is based on the location of the tumor, the person's age and their medical history. The various treatment options for acromegaly are listed below:

• Surgery - The goal of surgery is to remove the pituitary tumor, which stops the overproduction of GH and relieves any pressure on the surrounding tissue. There are two types of surgery, the first is transsphenoidal surgery which involves making an incision into the gum and then the septum through to the nasal cavity, then removing the pituitary tumor. The second is endonasal transphenoidal surgery and is much like the first method only the nasal cavity is reached via the nostrils using microsurgical instruments. The second method is newer and much less invasive. The removal of the tumor should mean the GH levels go down, however they do not usually return to normal and further treatment involving medication may be required.
• Radiation Therapy - This type of therapy can be used either as part of a combination of treatments or as the main treatment method. It is mainly used after surgery, if some of the tumor cells remain. It may be used in conjunction with medication to help lower the GH levels. There are two different ways a person would undergo radiation therapy. The first is called conventional radiation therapy and is given 5 days a week, for up to 6 weeks. A person's GH levels may not return to normal for as long as ten years with this method. The second is stereotactic radiosurgery and consists of a number of highly focused intense beams of radiation all pointed at the tumor. As the beams are focused on the tumor, the damage to surrounding tissue is reduced. This method involves fewer sessions that the first, and can reduce GH levels in less time.
• Medication - Acromegaly can be treated with medication alone if surgery is considered too high risk or impossible due to the location of the tumor. The outcome of the medication is to stop the rapid growth brought on by the increased GH levels. There are a few different types of medication that include SSAs (somatostatin analogues), dopamine agonists and GHRAs (growth hormone receptor antagonists).

Written by Mike Paddock
Copyright: Medical News Today
Not to be reproduced without permission of Medical News Today

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