Acromegaly is characterized by excessive growth due to oversecretion of growth hormone, which is produced in the liver and other tissues and is secreted by the anterior pituitary gland. Oversecretion of growth hormone is often caused by the presence of a benign pituitary tumor (adenoma) but can also be caused by lung and pancreas tumors that stimulate the excessive production of substances similar to growth hormone (Berkow, Beers, & Fletcher,).
The prevalence of acromegaly is approximately 50–70 cases per million. Three or four infants who will develop acromegaly are born per million births (Novartis Pharmaceuticals Corporation,). It has been estimated that there are 15,000 cases of acromegaly within the United States. Its onset most commonly occurs between the ages of 30 and 50 years (Berkow et al.,), but it is not usually diagnosed until 10 years after increased hormone secretion has begun (Novartis Pharmaceuticals Corporation,). Reasons accounting for this delay of diagnosis include slow development of symptoms, a variety of clinical signs and symptoms, and the need to rule out other medical conditions with similar signs and symptoms (Novartis Pharmaceuticals Corporation,). If excessive growth of the same nature occurs by the age of 10 years, it is referred to as gigantism (accelerated growth). Acromegaly is diagnosed through the presence of elevated blood levels of growth hormone (GH) or insulin-like growth factor I (IGF-I). X rays confirm the thickening of bones. Pituitary tumors are the cause of acromegaly in 90% of cases (Tierny, McPhee, & Papadakis,). A CT scan or magnetic resonance imaging (MRI) examines the site and size of possible tumors. If there is no tumor, these same tests can be used to detect the enlargement of organs or the source of excessive growth hormone excretion.
Additional symptoms associated with acromegaly include carpal tunnel syndrome, sleep apnea, goiter, colon polyps, and hypertension. Weight gain is frequent and largely attributable to muscle and bone growth. Diabetes sometimes occurs due to insulin resistance, and arthritis and joint pain are common. The heart may become enlarged, increasing the chance of heart failure. Headaches are common due to pressure caused by the tumor. As tissues enlarge, they may compress nerves including the optic nerve, sometimes resulting in loss of vision.
Treatment of acromegaly is primarily medical. Initially, the tumor is either removed through surgery or destroyed through radiation therapy. Medication such as octreotide or bromocriptine slow or block the production of growth hormone (Berkow et al.,). When surgical treatment is successful, normal pituitary function returns, resulting in the decrease of soft tissue swelling. Bone enlargement, however, is permanent (Tierney et al.,). In children, because excessive growth hormone is secreted before the bones stop growing, the result is abnormal height and excessive bone growth.
Acromegaly, referred to as gigantism when seen in children, is not necessarily accompanied by cognitive deficiencies. Special education issues are most often related to physical accommodations or services such as occupational therapy.
Unlike adults with acromegaly, children who are treated for gigantism do not become deformed. Other symptoms persist, however, such as swollen tissue around bones, delayed puberty, and incomplete development of the genitals (Berkow et al.,). One study has shown that the life expectancy of individuals with acromegaly is approximately 10 years lower than that of nonacromegalic individuals (Novartis Pharmaceuticals Corporation,).
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What Is Acromegaly? This chapter includes text excerpted from “Acromegaly,” National Institute of Diabetes and Digestive and Kidney Diseases (NID