Acromegaly

What is Acromegaly?

Definition:
Acromegaly is a chronic metabolic disorder caused by the presence of too much growth hormone. It results in gradual enlargement of body tissues including the bones of the face, jaw, hands, feet, and skull.

Alternative Names: Somatotroph adenoma; Growth hormone excess

Causes, incidence, and risk factors:
Acromegaly occurs in about 6 of every 100,000 adults. It is caused by abnormal production of growth hormone after normal growth of the skeleton and other organs is complete. Excessive production of growth hormone in children causes gigantism rather than acromegaly.

The cause of the increased hormone secretion is usually a benign tumor of the pituitary gland. The pituitary gland, which is located just below the brain, controls the production and release of several different hormones including growth hormone.

There are no known risk factors for acromegaly other than a prior history of a pituitary tumor.

Symptoms:

• Enlarged hands
• Enlarged feet
• Widened fingers or toes due to skin overgrowth with swelling, redness, and pain
• Enlarged jaw (prognathism) and tongue
• Enlarged facial bones
• Thickening of the skin, skin tags
• Enlarged sebaceous glands
• Hoarseness
• Headache
• Easy fatigue
• Excessive sweating
• Decreased muscle strength (weakness)
• Limited joint mobility
• Joint pain
• Carpal tunnel syndrome
• Widely spaced teeth
• Swelling of the bony areas around a joint

Additional symptoms that may be associated with this disease:

• Weight gain (unintentional)
• Hair, excessive on females

Signs and tests:

• The level of growth hormone is high.
• The level of IGF-1 (insulin-like growth factor 1) is high.
• A spine X-ray shows abnormal bone growth.
• A cranial MRI or cranial CT scan may show a pituitary tumor.
• An echocardiogram may show a leaky mitral valve or a leaky aortic valve.

This disease may also alter the results of the following tests:

• Fasting plasma glucose (high)
• Glucose tolerance test (too high at 2 hours)
• Creatinine
• Creatinine - urine
• 17-ketosteroids
• 17-hydroxycorticosteroids

Treatment:
Microsurgery to remove the pituitary tumor causing this condition corrects the abnormal growth hormone secretion in most patients. This surgery may not be available to patients in isolated geographic locations, so travel to a larger metropolitan area may be necessary for treatment.

Radiation of the pituitary gland is used for people who do not respond to the surgical treatment. However, the reduction in growth hormone levels after radiation is very slow.

Treatment with the medications cabergoline or octreotide may control growth hormone secretions in some people. Pegvisomant, a new drug that directly blocks the effects of growth hormone, has been shown to improve symptoms of acromegaly in recent studies. These medications may be used as initial treatment if surgery is unavailable or if the person is unable to tolerate surgery.

After treatment, periodic evaluation is necessary to ensure the normal functioning of the pituitary gland. Yearly evaluations are recommended.

Support Groups:

Expectations (prognosis):
Pituitary surgery is successful in up to 80% of patients, depending on the size of the tumor and the experience of the surgeon.

Without treatment the symptoms are progressive, and the risk of cardiovascular disease increases.

Complications:

• hypopituitarism (too little secretion of other pituitary hormones)
• high blood pressure
• glucose intolerance or diabetes
• cardiovascular disease
• carpal tunnel syndrome
• sleep apnea
• arthritis
• colonic polyps
• uterine fibroids
• spinal cord compression
• vision abnormalities

Calling your health care provider:
Call your health care provider if symptoms of acromegaly are present or if symptoms do not improve with treatment.

Prevention:
No measures exist to prevent the initial condition, but early treatment may prevent any worsening of complications associated with this disease.