Acromegaly, growth hormone excess

Since radioimmunoassays are available, it is now possible to diagnose the early stages of acromegaly and to follow the hormone levels as the disease develops. Furthermore, new types of growth hormone excess have been discovered a disease has been described in which excess growth hormone is observed in the absence of a pituitary hormone. The disease is believed to result from abnormal stimulation of the hypothalamic secretion. 

Acromegaly A pathologic condition characterized by excessive production of growth hormone during adulthood after epiphyseal (long bone) fusions have completed. 

The dopamine D2 agonists bromocriptine and cabergoline (pp. 114, 188) inhibit prolactin-releasing AH cells (indications suppression of lactation, prolactin-producing tumors). Excessive, but not normal, growth hormone release can also be inhibited (indication acromegaly) (3). 

Acromegaly is almost always caused by a pimitary growth hormone (GH)-secreting adenoma, and transsphenoidal surgery is normally considered to be the first treatment of choice. A number of patients are not cured by surgery, however, and GH hypersecretion is nowadays treated actively, because of its known associated excess mortality. 

The incidence of malignancy is increased in acromegaly, in which growth hormone is present in excess. Patients treated with growth hormone have therefore been carefully monitored. The cancer risk of growth hormone has been reviewed (93). 

Clinical studies with SMS 201-995 80 b) have shown that the growth-hormone concentration in the plasma can be reduced and, in this way, acromegaly (excessive growth of acral regions such as nose, ears, chin, hands, and feet) can be treated by subcutaneous administration. 

EXCESS results in a normally proportioned giant when overproduction occurs in childhood. Overproduction in an adult results tn acromegaly. Such individuals have abnormally proportioned growth features, especially enlarged hands, feet and jaw. There may be hyperglycemia, as growth hormone is also involved in glucose metabolism. 

In acromegaly, excess growth hormone causes diabetes, hypertension and arthritis. The former two lead to a 2-fold excess in cardiovascular mortality. Surgery is the treatment of choice. Growth hormone secretion is reduced by octreotide and other somatostatin analogues and to a lesser degree by bromocriptine (see Index). 

The incidence of malignancy is increased in acromegaly, in which growth hormone is present in excess. Patients treated with growth hormone have therefore been carefully monitored. The first report of leukemia in Japanese children treated with growth hormone (73) prompted a worldwide survey. There have been reports of 44 new cases of leukemia in growth hormone recipients, of which only 20 were acute lymphoblastic leukemia. This is much less than the expected 80-85% of new childhood leukemia (74). 

C. An excess of growth hormone (GH) after epiphyseal closure causes acromegaly, a condition characterized by enlargement of the jaw, nose, hands, feet, and skull. 

Endocrinopathies Excessive production of insulin counterregulatory hormones can cause diabetes mellitus. Examples include excessive production of growth hormone (acromegaly), cortisol (Cushing s syndrome), epinephrine (pheochromocytoma), and glucagon (glucago-noma). 

Destruction of the pituitary gland may result in secondary hypothyroidism, hypogonadism, adrenal insufficiency, growth hormone deficiency, and hypoprolactinemia. The formation of certain types of pituitary tumors may result in pituitary hormone excess. Pituitary tumors may also physically compress the pituitary and prevent the release of the trophic hypothalamic factors that regulate pituitary hormones. In this chapter, the pathophysiology and role of pharmacotherapy in the treatment of acromegaly, short stature, hyperprolactinemia, and panhypopituitarism will be discussed. 

Acromegaly—A pathologic condition characterized by excessive production of growth hormone. 

The development of radioimmunoassays has permitted measurement of the amount of growth hormone in the blood of acromegalics. The normal blood level may be increased up to 100 times in acromegalics. Patients who develop no further symptoms of acromegaly continue to have excessive amounts of growth hormone in their blood. 

The condition which results from excess growth hormone secretion in adults, the usual cause being a pituitary adenoma. The condition is characterized by increases in bulk of the bones and soft tissues, especially of the jaw, hands and feet. Because growth hormone is involved in glucose homeostasis, impaired glucose tolerance can occur. Acromegaly can be diagnosed biochemically by ... 

There may be excessive amounts of hyperglycaemic agents present, e.g. glucocorticoids (as in Cushing s disease or steroid therapy) or growth hormone (as in acromegaly). 

Hyperglycaemia is found in diabetes mellitus when insufficient insulin is present. This may be a primary condition or secondary to other conditions, e.g. when insulin antagonists are present in excess as in Cushing s disease (due to excess glucocorticoids), acromegaly (due to excess growth hormone) or phaeochromocytoma (due to excess adrenaline). 

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