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Growth Hormone Excess & Deficiency Treatment: Hormone Therapy
Growth Hormone Excess: Treatment Options
Because excess GH — acting alone or together with excess IGF-1 — produces adverse health effects, eliminating the hormone imbalance and reducing the levels to normal is desirable. Surgery, medication and/or irradiation of the pituitary gland may be appropriate to achieve these goals.
Surgery. The most common cause of GH hypersection is a non-cancerous tumor of the pituitary gland, which produces GH. For these patients, surgery to remove the tumor is the treatment of choice. Unfortunately, in other cases there is a generalized enlargement of the pituitary gland, which is called pituitary hyperplasia. This makes surgery impossible since there is not a discrete area to be removed.
If surgery does not normalize the GH level, or if a patient is not a candidate for surgery, other therapies are used. Medication and irradiation of the pituitary gland are options as primary or supplemental therapy.
Medications. Three types of drugs are now available for the treatment of GH excess — somatostatin analogues, GH receptor antagonists, and dopamine agonists. These medications do not “cure” the disorder but work, instead, to reduce levels of GH or IGF-1. These medications must be taken for life if surgery or irradiation fails to eliminate the cause of GH excess.
Pituitary Irradiation. Radiation therapy is another therapeutic approach for patients with acromegaly, who have undergone pituitary surgery and still have excess GH. This remaining overproduction of GH may occur if the pituitary gland tumor removed during surgery had spread beyond the pituitary gland. Because complete removal of invasive tumors is often challenging, additional therapy may be needed to achieve normal GH and IGF-1 levels.
Although pituitary irradiation can ultimately achieve complete remission, its disadvantage is the time needed to reach that goal. Conventional radiation therapy may take 10 years or longer to be fully effective. Newer methods of focused delivery — such as gamma knife, proton beam, or linear accelerator — of a high dose of radiation to the tumor often affect an earlier remission than the conventional method. Unfortunately, there still may be a significant delay.
Although it takes longer to attain remission with irradiation than with medications, once remission is reached, the effects of irradiation are permanent. Patients may need to take medication until the radiation therapy achieves its effect.
Unlike in adults, radiation is consisted a last resort in children with GH excess, as there as concerns about its effects on the developing brain.
Long-term Follow-up and Prognosis
Patients treated for acromegaly need to be monitored to make sure that GH excess does not return. Patients should also be monitored for medical problems that are associated with acromegaly, which include heart disease, high blood pressure, colon polyps, and high blood sugar. They also need to be watched for signs of hypopituitarism, caused by low levels of pituitary hormones.
Loss of other pituitary functions can result from the pituitary gland tumor mass. It also can be a complication of surgery or radiation therapy. Pituitary failure requires appropriate hormone replacement therapy.
Treating acromegaly to reduce excess GH is beneficial to patients. Persons with untreated acromegaly, for example, have a mortality rate that is two to three times higher than the general population. Mostly this is due to cardiovascular and respiratory complications. Decreased survival is more likely when the GH level is higher and when diabetes mellitus is present.
Reducing the hormone imbalance so the levels of GH and IGF-1 are normal, however, may be associated with a return to normal life expectancy.
Growth Hormone Deficiency : Treatment
GH is usually administered as a daily injection under the skin. Because adults tend to have more side effects than children, their treatment often begins at a low dose and then is raised gradually.
The doses of GH used to treat children — especially adolescents — are often much higher than those in adults. Younger adult patients require higher doses than older ones, and women require more than men. Women taking estrogen by mouth may need a higher dose of GH.
Long-term Follow-up and Prognosis
Children. Children should be evaluated every three to six months to monitor their GH treatment. The best indicators are gains in height and rate of growth. Follow-up is important to assure compliance with the daily injections, to detect and manage possible side effects, monitor growth progress, and to adjust dosage periodically.
If patients have been compliant with their injections and their growth remains lower than desirable then the GH dose may be increased within the guidelines approved by the U.S. Food and Drug Administration (FDA). If the patient’s serum IGF-1 levels are well above the normal range at any time, then a decreased dose should be considered.
The children with the best chance of reaching their height potential are those who start GH therapy as soon as the diagnosis is made, and continue it through adolescence. With the current GH products, most children with GHD reach normal adult stature. When children with GHD reach late adolescence, tests should be done to see if they still need GH therapy into adulthood.
Blood sugar levels may need to be monitored as well. There is great variability in changes in insulin sensitivity because of differences in body composition, age, and genetic predisposition. Patients with type II diabetes need special attention because growth hormone therapy hinders control of that disease until the patient loses excess abdominal fat. Follow-up visits, even for those on lifetime replacement therapy, should be scheduled at least twice a year.
Undesirable effects of growth hormone therapy in childhood are exceedingly rare. The most troubling side effects in children are increased intracranial pressure and a hip disorder called slipped capital femoral epiphysis. Intracranial pressure should be seen by a doctor who may “treat” it by stopping the dose for a few days and then slowly increasing it. This usually occurs only in the first month of therapy. Muscle and joint pain is quite uncommon in kids. Growth hormone is known to cause small alterations in insulin and glucose levels. While it may “unmask” underlying type II diabetes, there is no evidence that GH causes diabetes.