Muscle atrophy is the wasting or loss of muscle tissue.
Muscle wasting; Wasting; Atrophy of the muscles
There are two types of muscle atrophy.
Disuse atrophy occurs from a lack of physical exercise. In most people, muscle atrophy is caused by not using the muscles enough. People with sedentary jobs, medical conditions that limit their movement, or decreased activity levels can lose muscle tone and develop atrophy. This type of atrophy can be reversed with exercise and better nutrition.
Bedridden people can have significant muscle wasting. Astronauts who are away from the Earth's gravity can develop decreased muscle tone and lose calcium from their bones after just a few days of weightlessness.
The most severe type of muscle atrophy is neurogenic atrophy. It occurs when there is an injury to, or disease of, a nerve that connects to the muscle. This type of muscle atrophy tends to occur more suddenly than disuse atrophy.
Examples of diseases affecting the nerves that control muscles:
Although people can adapt to some degree of muscle atrophy, even minor muscle atrophy usually causes some loss of movement or strength.
Some muscle atrophy occurs normally with aging. Other causes may include:
An exercise program (under the direction of a therapist or doctor) is recommended to help treat muscle atrophy. This may include exercises in water to reduce the muscle workload, and other types of rehabilitation.
People who cannot actively move one or more joints can do exercises using braces or splints.
Call your doctor for an appointment if you have unexplained or long-term muscle loss. You can often see this when you compare one hand, arm, or leg to the other.
The doctor will perform a physical examination and ask questions about your medical history and symptoms, including:
The doctor will look at your arms and legs and measure muscle size to try to determine which nerve or nerves are affected.
Tests that may be performed include:
Barohn RJ. Muscle Diseases. In: Goldman L, Ausiello D, eds. Cecil Medicine. 23rd ed. Philadelphia, Pa: Saunders Elsevier; 2007: chap 447.