Atrophy is a symptom of many medical conditions. It causes the wasting of tissue, muscle or nerve cells. In healthy bodies, cells die and are replaced at a constant rate. Atrophy occurs when cells begin to die without being replaced. Eventually, the associated tissue begins to shrink and lose its ability to function effectively.

Atrophy can occur anywhere in the body, although the most common types of atrophy affect the muscles and the brain (cerebral atrophy). Muscular atrophy can be caused by diseases (e.g. muscular dystrophy, Lou Gehrig’s disease), malnutrition or simple lack of muscle use. Muscular atrophy is particularly common following the injury of a part of the body that is usually active (e.g. an arm or a leg). When the body part remains inactive, the muscles begin to waste. Muscular atrophy is also common in older people who are not active, where it leads to frailty and an increased risk of falls.

Cerebral atrophy is a symptom that accompanies many diseases and injuries of the brain. It occurs following the loss of brain neurons (nerve cells) and their connections, which are essential for most aspects of thought and action. Atrophy can also occur in other areas of the body (e.g. optical atrophy, vaginal atrophy, breast atrophy) and in mucous membranes, the moist lining of passageways in the body (e.g., mouth, nose, eyes and intestines).

Atrophy can range from mild to severe. For example, people with mild muscle atrophy may barely notice a difference in strength, although they may find it more difficult to perform certain tasks such as carrying heavy items or climbing stairs. Severe atrophy, on the other hand, can affect many aspects of a person’s life. Severe brain atrophy, for example, may cause dementia, paralysis or even result in coma.