Acromegaly is a chronic condition characterized by the presence of excess growth hormone (GH) in your blood. The high levels of the hormone will eventually cause your bodily tissues to grow larger than would be expected if your body was producing normal levels of growth hormone.
Acromegaly is most commonly caused by a noncancerous tumor of the pituitary gland. It should not be confused with gigantism, which is caused by an excess of growth hormone in children. By definition, acromegaly can only occur after your bones and other organs have stopped growing, usually around 18 years for women and slightly older for men.
How common is acromegaly?
The prevalence of acromegaly is approximately one case per every 25,000 adults.
Who gets acromegaly?
Acromegaly affects only adults and most commonly occurs between the ages of 30 and 50 years old. Excess growth hormone production in prepubescent or pubescent children is called ‘gigantism.’
How is acromegaly diagnosed?
Elevated levels of growth hormone (GH) and insulin-like growth factor-1 (IGF-1) in your blood confirm the diagnosis. The disease may be suspected if your doctor observes abnormal bone growth, enlarged or dysfunctional heart, or a tumor of the pituitary gland on magnetic resonance imaging (MRI).
Symptoms of acromegaly include:
- Enlargement of your hands, feet, and head (specifically the forehead and jaw)
- Carpal tunnel syndrome
- Oily skin and excessive sweating
- Tiredness, fatigue, and depression
- Impotence, loss of libido
- Interrupted menstrual cycle
- Heart disease and heart enlargement
- Diabetes mellitus
- Sleep apnea
- Loss of vision
- Colon cancer
Surgery is the best form of treatment and the only way to achieve a cure. Your surgeon will gain access to your pituitary gland using the transsphenoidal approach—so named because the route your surgeon takes crosses, or transects, your sphenoid bone. This bone is located behind your nose mostly within your skull.
Using precise surgical instruments, your surgeon will make an incision through your nasal cavity to create an opening in your sphenoid bone. Once your surgeon gains access to your sphenoid sinus (the air-filled area behind the sphenoid bone), further incisions will be made until a hole is created in the sella turcica—the bone that cradles and protects your pituitary gland.
Once your tumor appears in the operative field, removal of the tumor can proceed. Your surgeon will use high magnification to help distinguish normal pituitary tissue from the tumor.
After the tumor has been removed, your surgeon will clean the tumor cavity and seal it off. At Barrow, our surgeons specialize in two types of surgery for pituitary adenomas:
- Microsurgery – uses a powerful operating microscope to help your surgeon distinguish between tiny structures in and around your pituitary gland
- Endoscopic surgery – uses small tubes and a tiny camera to help your surgeon remove your tumor in small pieces
Both surgeries aim to minimize trauma to the tissue surrounding your pituitary gland while facilitating a speedy recovery with as little pain or discomfort as is possible. Each technique has its own inherent advantages and disadvantages, and your surgeons will work with you to help determine which is the best fit for you.
Most patients are able to return home the day after their surgery for removing a TSH adenoma. Nasal packing is seldom required.
Gamma Knife radiosurgery is a highly advanced form of radiotherapy that is used to achieve similar results to the traditional surgical techniques described above. However, with Gamma Knife it can take several years for growth hormone (GH) levels to return to normal, rather than days or weeks as with traditional surgery.
The ‘knife’ in this surgery is actually made up of many small beams of radiation focused on a single point. Each individual beam is too weak to damage healthy tissue, but at the point where the beams converge they deliver a dose of radiation that is lethal to the tumor.
Gamma Knife is an outpatient procedure, does not involve any incisions, and requires only brief sedation under general anesthetic.
Pharmacological Treatment and Hormone Therapy
Treatment with medical agents is possible if surgery does not cure your acromegaly or if surgery is contraindicated for you. Medicines are sometimes prescribed before surgery to improve the likelihood of a good outcome.
- Octreotide or lanreotide are synthetic forms of somatostatin—a hormone that decreases growth hormone production—and can help lower growth hormone levels. These medications are often effective for the long-term control of acromegaly but they can only be administered by injection every two to four weeks. If your tumor is particularly large, these drugs may be administered before your surgery. Due to their side effects, surgery is preferable to achieve long-term cure in most cases.
- Bromocriptine and cabergoline belong to a class of drugs called ‘dopamine agonists’ and have the ability to lower insulin-like growth factor 1 (IGF-1) and growth hormone levels in about half of the people treated with them (although your symptoms could improve even if your IGF-1 and growth hormone levels do not decrease). These medications may not be as effective as the synthetic hormones octreotide and lanreotide, but they are less expensive and more convenient to administer because no injection is required.
- Pegvisomant is a recently developed drug that blocks the action of growth hormone in your body, thereby lowering IGF-1 levels. It must be administered daily by subcutaneous (beneath the skin) injection. It is another option if you do not respond to surgery or other medications, or if your body does not tolerate other treatments.
- Date of last review: December 7, 2016
- Author: Andrew S. Little, MD