Acromegaly and Gigantism - Pathology Usmle step 1 Lecture

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Acromegaly and Gigantism - Pathology Usmle step 1 Lecture

Development of abnormally large size due to the excessive growth of the long bones. Caused by hyperpituitarism before the completion of the normal ossification process (commonly seen in children).

This is in contrast to acromegaly, which results from hyperpituitarism after the completion of the ossification process (commonly seen in adults). Typically accompanied by muscular weakness and sexual impotence.

Most common cause is pituitary-associated gigantism.

Acromegaly results from persistent hypersecretion of growth hormone (GH). Excess GH stimulates hepatic secretion of insulin-like growth factor 1 (IGF-1), which causes most of the clinical manifestations of acromegaly.

The most common cause of acromegaly is a somatotroph (growth hormone [GH]-secreting) adenoma of the anterior pituitary. These adenomas account for about one-third of all hormone-secreting pituitary adenomas

The clinical features of acromegaly are attributable to high serum concentrations of both growth hormone (GH) and insulin-like growth factor 1 (IGF-1), which is GH-dependent. Excess GH and IGF-1 have both somatic and metabolic effects. The somatic effects include stimulation of growth of many tissues, such as skin, connective tissue, cartilage, bone, viscera, and many epithelial tissues.

?The metabolic effects include nitrogen retention, insulin antagonism, and lipolysis.