A 60-year-old man presents to his family physician with severe headache and weakness (Figure 237-1). He also noted enlargement of his hands (Figure 237-2), which made him remove his wedding ring when it became too tight, and feet (his shoe size had increased). He said his voice seemed to be deeper and his hands feel doughy and sweaty. Laboratory testing reveals an elevated insulin-like growth factor (IGF)-1, and there is a failure of growth hormone (GH) suppression following an oral glucose load confirming the diagnosis of acromegaly. Computed tomography (CT) scan of the head demonstrates a pituitary adenoma.
A 60-year-old man with acromegaly. Note the coarse facial features and moderate prognathism (Protrusion of the lower jaw). (Reproduced with permission from Richard P. Usatine, MD.)
The man in Figure 237-1 with acromegaly producing hands that are large and doughy with widened fingers. (Reproduced with permission from Richard P. Usatine, MD.)
Acromegaly is a condition of excessive linear and organ growth usually caused by autonomous GH hypersecretion from a pituitary tumor.
Rare (5/1,000,000 adults).1
Most typically caused by a pituitary somatotroph macroadenoma. It may also be caused by growth hormone–releasing hormone (GHRH) excess from lesions of the pancreas, lung, or ovaries, or from a chest or abdominal carcinoid tumor.
The disorder is usually sporadic, but may be familial (<5%) and has been associated with other endocrine tumors (e.g., multiple endocrine neoplasia type I).1
In a Spanish multicenter epidemiologic study, the reported mean age at diagnosis was 45 years.2
The occurrence of GH hypersecretion in children and adolescents, prior to epiphyseal closure, causes gigantism. In one study, early-onset gigantism was caused by an Xq26.3 genomic duplication.3
ETIOLOGY AND PATHOPHYSIOLOGY
The clinical signs and symptoms of acromegaly result from GH excess that stimulates linear and organ growth (through IGF-1), soft-tissue swelling, and chondrocyte action.
Acromegaly is also associated with insulin resistance and an increased risk of cardiovascular disease; the latter appears to be a result of pressure-related arterial and left ventricular stiffening rather than atherosclerotic disease.4 There may be gender-specific metabolic profiles in patients with acromegaly, with women having greater insulin resistance and features of metabolic syndrome compared to men.5
An increased risk for several cancers among these patients may be a result of the proliferative and antiapoptotic activity associated with increased circulating levels of IGF-1.
The diagnosis of acromegaly is established by documenting autonomous GH hypersecretion and by pituitary imaging.