Acromegaly is condition that is nearly always caused by a pituitary adenoma, a tumor of the pituitary gland. The term acromegaly literally means enlarged extremities; acro means extremity and megaly means enlargement of.
Our comprehensive approach to diagnosis and treatment of pituitary conditions, including acromegaly, sets the UCLA Pituitary Tumor Program apart. Our physicians treat a high volume of patients every year and perform over 100 pituitary surgeries a year, making us one of the top programs in the United States.
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The normal pituitary gland secretes growth hormone (GH):
GH has direct effects on the body, such as on muscle growth. It also acts on specialized gland cells in the liver:
A pituitary tumor that secretes an excessive amount of GH causes changes in the body that lead to disfigurement. If the disfigurement severely affects the internal organs, it could lead to death.
While acromegaly is nearly always caused by an adenoma, there are rare cases when it occurs due to excess growth hormone secretion outside the pituitary. These tumors most commonly occur:
Acromegaly typically presents in adulthood. Because the physical changes occur so slowly, it can take an average of seven to eight years before the condition is diagnosed. If a pituitary tumor produces an excessive amount of GH in childhood, gigantism occurs.
Serious conditions related to longstanding, untreated acromegaly, include:
Acromegalic patients are at increased risk of developing other tumors or lesions of the body:
If a pituitary growth hormone producing tumor develops in childhood before bone growth is completed, gigantism results. Pituitary giants can grow over seven feet tall.
Macroadenomas that grow upward into the brain cavity can compress the optic chiasm. Vision problems can include:
More severe hypopituitarism can lead to hypothyroidism or abnormally low cortisol levels, which may be life threatening. Symptoms of severe hypopituitarism include:
Changes in hormonal function can cause electrolyte imbalance in the blood, typically low sodium levels (hyponatremia). Symptoms could include:
A pituitary adenoma may be suspected based on symptoms, the medical history, and physical findings of acromegaly. Explaining your symptoms is a crucial part of diagnosis, as your doctor uses the information to determine whether a pituitary tumor is secreting an excess of hormones and if there is evidence of pituitary insufficiency. Physicians at the Pituitary Tumor Program at UCLA have vast experience in diagnosing pituitary conditions.
Standard diagnostic tests include:
Doctors will order blood tests, specifically looking for an elevated level of IGF-1. In some rare cases, usually in premenopausal women, the GH levels can be high even though the IGF-1 levels are normal. This is an estrogen-resistant phenomenon.
Normally, the pituitary glands secrete GH in a pulsatile fashion, meaning the level increases and decreases significantly throughout the day. This affects diagnosis in two ways:
IGF-1 is released in a more steady fashion. Its levels do not go up and down quickly, making it a better hormone to measure to screen for acromegaly.
You may be asked to undergo an oral glucose tolerance test (OGTT) to confirm the diagnosis. Drinking 75 grams of a glucose solution should lower the GH level to lower than one nanogram per milliliter. In acromegalics, this suppression does not occur and may in fact increase.
Learn more about hormone testing at the UCLA Pituitary Tumor Program.
One method we use to detect pituitary tumors is a magnetic resonance imaging (MRI) scan of the pituitary gland. We use a special MRI pituitary protocol to properly visualize the tumor.
Smaller tumors may not be visible using computed tomography (CT) scans.
The vast majority (90%) of GH-secreting tumors are macroadenomas.
The optimal treatment of acromegaly depends on multiple factors, including:
Invasive tumors may not be able to be cured surgically.
Typically, more than one specialist is involved in managing pituitary adenomas. At the Pituitary Tumor Program, your medical team includes a special endocrinologist called a neuro-endocrinologist who has specific expertise in the treatment of acromegaly.
Treatment options include:
Your doctor may recommend surgically removing the tumors as your best chance for a cure. If the tumor invaded beyond the sella (the space where the normal pituitary gland sits), however, there is a lower chance of a surgical cure. In that case, your doctor may recommend other treatment options, such as medication or radiation therapy.
Patients should strongly consider seeking the care of an experienced neurosurgeon, one whom performs a large number of pituitary surgeries each year. Studies have shown:
If the pituitary adenomas require surgery, typically the best procedure is through a nasal approach. Our neurosurgeons who specialize in pituitary tumor surgery are experts in the minimally invasive endoscopic endonasal technique. This procedure removes the tumor while minimizing complications, hospital time and discomfort. This advanced technique requires specialized training and equipment.
Very large tumors that extend into the brain cavity may require opening the skull (craniotomy) to access the tumor. Our surgeons are also experts in the minimally invasive "key-hole" craniotomy, utilizing a small incision hidden in the eyebrow.
In recent years, the medical treatment of acromegaly has improved. In some cases, doctors use medication, and not surgery, as the first course of treatment. However, in many cases, patients require both medical and surgical therapies to control acromegaly.
For some patients, surgery or medication is not sufficient to control the acromegaly. In these cases, doctors may recommend stereotactic radiosurgery. Stereotactic radiosurgery is a technique in which doctors aim a highly focused dose of radiation to the tumor. It takes an average of 18 months to lower the GH and IGF-1 levels.
The radiation beam is designed to target only the tumor. The surrounding brain structures receive only a fraction of the radiation dose and are typically unharmed, with the exception of the normal pituitary gland.
A consequence of radiation treatment is that it can cause delayed pituitary failure. This typically occurs several years after treatment, and therefore continued long-term follow-up with an endocrinologist is important. Hormone replacement may be required.
The UCLA Pituitary Tumor Program has clinical trials testing newer medications for the treatment of acromegaly.
To schedule an appointment with one of our physicians at the Pituitary Tumor Program, please call (310) 825 5111.
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