Atrophy

Lore & Background

Atrophy is a normal part of development, as seen in the shrinking of the thymus in early childhood and the tonsils in adolescence. In old age, it contributes to loss of teeth, hair, thinning skin, weakening muscles, and sluggish mental activity. Disuse atrophy of muscles and bones can occur after prolonged immobility, such as extended bedrest or having a body part in a cast, and can usually be reversed with exercise unless severe.

Reader's Guide

Atrophy is significant in medical practice as a marker of disease and aging. Pathological atrophy can result from diseases like cancer and AIDS, which induce cachexia, or from conditions like congestive heart failure and liver disease. Muscle atrophy also occurs in motor neuron diseases such as amyotrophic lateral sclerosis (ALS) and in muscle diseases like muscular dystrophy. Gland atrophy, such as adrenal atrophy from prolonged glucocorticoid use or breast atrophy from estrogen reduction, illustrates the role of hormonal support. Vaginal atrophy in post-menopausal women is consistent with atrophy's homeostatic role, as the body shuts down the reproductive system. Research into preventing muscle loss in immobile patients has identified a drug that blocks a protein involved in atrophy, but its long-term effect on the heart precludes routine use. Atrophy contrasts with hypoplasia, which is reduction in cellular numbers before normal maturity.

Did You Know?

• Atrophy can occur as part of normal development, such as the involution of the thymus in early childhood.
• Disuse atrophy from prolonged immobility can usually be reversed with exercise unless severe.
• The adrenal glands atrophy during prolonged use of exogenous glucocorticoids like prednisone.
• One drug tested in mice blocked a protein involved in muscle atrophy but had long-term effects on the heart.