acromegaly

Acromegaly is what happens when an adult's body keeps getting too much growth hormone. Long after childhood, when the long bones can no longer grow in length, the excess hormone instead thickens and enlarges tissues — most visibly the hands, feet, jaw, and facial features. The name comes from Greek for “enlarged extremities.”

Almost always the cause is a benign pituitary tumor that oversecretes growth hormone. The hormone then drives the liver to make large amounts of IGF-1, and it is largely this IGF-1 that produces the slow tissue and bone overgrowth throughout the body.

The changes creep on gradually over years, so they are easy to miss at first. People may notice rings or shoes no longer fit, coarsening facial features, a deeper voice, sweating, joint aches, headaches, and an enlarged tongue. Acromegaly also carries serious internal risks, including high blood pressure, diabetes, heart enlargement, and sleep apnea.

If the same excess of growth hormone begins in childhood, before the growth plates close, it causes very tall stature instead — a related condition called gigantism. Treatment of acromegaly aims to remove or shrink the tumor and lower growth hormone and IGF-1, typically by surgery, somatostatin analogs, or other medications.