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Muscle atrophy

Definition

Muscle atrophy is the wasting or loss of muscle tissue.

Alternative Names

Muscle wasting; Wasting; Atrophy of the muscles

Considerations

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 vigorous exercise or 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. This type of muscle atrophy tends to occur more suddenly than disuse atrophy.

Examples of diseases affecting the nerves that control muscles:

Even minor muscle atrophy usually causes some loss of movement or strength.

Causes

Some muscle atrophy occurs normally with aging. Other causes may include:

Home Care

An exercise program (under the direction of a therapist or doctor) is recommended. 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.

When to Contact a Medical Professional

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:

  • When did the muscle atrophy begin?
  • Is it getting worse?
  • What other symptoms do you have?

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:

Treatment may include ultrasound therapy and, in some cases, surgery to correct a contracture.

Arend WP, Lawry GV. Approach to the patient with rheumatic disease. In: Goldman L, Ausiello D, eds. Cecil Medicine. 23rd ed. Philadelphia, Pa: Saunders Elsevier; 2007: chap 277.


Review Date: 11/13/2008
Reviewed By: David C. Dugdale, III, MD, Professor of Medicine, Division of General Medicine, Department of Medicine, University of Washington School of Medicine; and Daniel B. Hoch, PhD, MD, Assistant Professor of Neurology, Harvard Medical School, Department of Neurology, Massachusetts General Hospital. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.
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