Growth hormone excess, pituitary adenoma, gigantism.

Pituitary tumors (usually benign adenomas) which produce excessive growth hormone result in changes in connective tissues. When epiphyseal plates have closed in adulthood, the result is acromegaly, so named for enlargement of the extremities. In childhood, such tumors produce gigantism. Growth hormone increases hepatic production of insulin-like growth factors I and II. These three hormones stimulate proliferation of bone and of soft tissue in cartilage, synovium, muscle, and joint capsules. The result is thickened digits, a thickened calvarium, enlarged mandible, hyperostosis of the frontal bone, hyperplasia of bursa, hypermobility of joints, cartilage degeneration, proximal muscle weakness, and myalgia. The arthritis of acromegaly is similar to osteoarthritis, but is distinguished in its early phases by joint space widening. There is joint hypermobility in the early stages, followed by bony hypertrophy and...