Acromegaly FAQs (cont.)
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How is acromegaly diagnosed?
Acromegaly is not an easy diagnosis, and it is frequently missed by doctors. Some of the signs and symptoms of acromegaly are very distinctive. Others are subtle and can be missed or misinterpreted. They are not always recognized as acromegaly because they develop so slowly. Once the diagnosis is suspected, you are usually referred to a specialist in hormonal disorders (endocrinologist).
Blood tests are used to help confirm the diagnosis. Measurement of IGF-1 level is considered the most reliable test for acromegaly. Another test measures levels of IGF-binding protein-3 (IGFBP-3), a protein that interacts with IGF-1. This test is used sometimes to help confirm the diagnosis of acromegaly.
Some health care providers measure what is called “glucose nonsuppressibility.” Blood glucose (sugar) suppresses growth hormone. The level of growth hormone in your blood is measured after you drink a sugary drink. The resulting high blood sugar level suppresses the growth hormone level in healthy people but not in people who have too much growth hormone.
A CT scan or MRI of the head is done to look for a pituitary tumor.
What treatments are available for acromegaly?
There are several treatment options in acromegaly. Whichever treatments are used, the goal is to relieve and reverse the symptoms of the disease. This is done in 2 ways: by normalizing production of growth hormone and IGF-1 and by reducing the effects of the pituitary tumor on the surrounding tissues. A secondary goal is to avoid damaging normal pituitary tissue.
Which treatments are used for a specific individual depend on the cause of the disease. For the large majority of cases caused by pituitary adenomas, treatments include surgery, drug therapy, and radiation therapy.
Will I have surgery?
Surgery is usually the first approach to treating acromegaly. For most people, this means removal of the pituitary tumor that is causing overproduction of growth hormone. The tumor is removed through an incision inside the nose. The operation is called transsphenoidal hypophysectomy. While technically not “brain surgery,” this is a very delicate operation calling for an experienced surgeon.
Is surgery a cure for acromegaly?
Surgery alone does bring about remission for some people, but not everyone. “Remission” in this case means to return levels of growth hormone and IGF-1 to normal. Remission is different than cure in that the disease can come back from remission.
If it is successful, this operation quickly relieves symptoms caused by the tumor pressing on adjacent tissue. Remission rates are high for small and large adenomas (microadenomas and macroadenomas, respectively).
People who are in remission after surgery usually need no further treatment. (Some people, however, require lifelong hormone replacement after pituitary surgery.) Growth hormone and IGF-1 levels after surgery usually indicate whether further treatment is needed. If these levels have not returned to normal, other treatment is needed.
What other treatments are available?
Often a combination of treatments is needed to put the disease in remission. No one combination of therapies works best for everyone.
Drug therapy is usually the second treatment. Drugs are given to normalize levels of growth hormone and IGF-1. Some drugs work by blocking production of growth hormone. Others work by preventing the growth hormone from stimulating production of IGF-1. In some cases, drugs are given to shrink the tumor.
Radiation therapy usually is reserved for adenomas that are not cured by surgery and drug therapy. Radiation also is used for people who cannot undergo surgery because of other medical problems. A majority of people who undergo radiation therapy have permanent loss of pituitary function. These people must take hormone replacement for the rest of their lives.
Drug or radiation therapy usually goes on for years. Radiation therapy can take anywhere from 18 months to several years to put the disease in remission.
What drugs are used to treat acromegaly?
Growth hormone receptor blockers are the newest category of drugs used for acromegaly. These drugs work by blocking the places on cells where growth hormone “docks.” If the excess growth hormone in the blood can’t dock on a cell, it can’t cause abnormal growth of the cell. The only drug in this category that has been approved by the US Food and Drug Administration for acromegaly is pegvisomant (Somavert). In early studies, this drug normalized IGF-1 level in more than 90% of people treated. Pegvisomant is given by a shot every day.
Somatostatin analogues act like a natural hormone called somatostatin, which stops secretion of growth hormone. The most widely used drug in this group by far is octreotide (Sandostatin). This drug works in most people who take it. It can be taken only as shots, either 3 times a day under the skin or once a month in the muscle.
Dopamine agonists promote the activity of dopamine, a chemical in the brain. These drugs work by stopping secretion of growth hormone by some pituitary tumors. The most widely used of these drugs is bromocriptine (Parlodel). It is popular because it comes in a convenient oral form and is much less expensive than octreotide. These drugs generally do not work as well as the growth hormone receptor blockers or the somatostatin analogues.
Medically Reviewed by a Doctor on 8/28/2014
Kathryn L Hale, MS, PA-C
Hasnain M Khandwala, MD, FRCPC
Arthur B Chausmer, MD, PhD, FACP, FACE, FACN, CNS
Francisco Talavera, PharmD, PhD
George T Griffing, MD
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