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A.D.A.M. Medical Encyclopedia [Internet]. Atlanta (GA): A.D.A.M.; 2013.

A.D.A.M. Medical Encyclopedia.

Muscle atrophy

Muscle wasting; Wasting; Atrophy of the muscles

Last reviewed: February 10, 2014.

Muscle atrophy is the wasting or loss of muscle tissue.

Considerations

There are two types of muscle atrophy.

  • Disuse atrophy occurs from a lack of physical activity. In most people, muscle atrophy is caused by not using the muscles enough. People with seated 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 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 muscle atrophy, 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 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.

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.

What to Expect at Your Office Visit

The health care provider 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 physical therapy, ultrasound therapy and, in some cases, surgery to correct a contracture.

References

  1. Chinnery PF. Muscle Diseases. In: Goldman L, Schafer AI, eds. Goldman's Cecil Medicine. 24th ed. Philadelphia, PA: Saunders Elsevier; 2011:chap 429.

Review Date: 2/10/2014.

Reviewed by: Joseph V. Campellone, M.D., Division of Neurology, Cooper University Hospital, Camden, NJ. Review provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the A.D.A.M. Editorial team.

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The information provided herein should not be used during any medical emergency or for the diagnosis or treatment of any medical condition. A licensed medical professional should be consulted for diagnosis and treatment of any and all medical conditions. Call 911 for all medical emergencies. Links to other sites are provided for information only — they do not constitute endorsementscof those other sites. © 1997–2011 A.D.A.M., Inc. Any duplication or distribution of the information contained herein is strictly prohibited.

Copyright © 2013, A.D.A.M., Inc.

A.D.A.M., Inc. is accredited by URAC, also known as the American Accreditation HealthCare Commission (www.urac.org). URAC's accreditation program is an independent audit to verify that A.D.A.M. follows rigorous standards of quality and accountability. A.D.A.M. is among the first to achieve this important distinction for online health information and services. Learn more about A.D.A.M.'s editorial policy, editorial process and privacy policy. A.D.A.M. is also a founding member of Hi-Ethics and subscribes to the principles of the Health on the Net Foundation (www.hon.ch).

The information provided herein should not be used during any medical emergency or for the diagnosis or treatment of any medical condition. A licensed medical professional should be consulted for diagnosis and treatment of any and all medical conditions. Call 911 for all medical emergencies. Links to other sites are provided for information only — they do not constitute endorsementscof those other sites. © 1997–2011 A.D.A.M., Inc. Any duplication or distribution of the information contained herein is strictly prohibited.

Copyright © 2013, A.D.A.M., Inc.

What works?

  • Drug treatment for spinal muscular atrophy types II and IIIDrug treatment for spinal muscular atrophy types II and III
    Spinal muscular atrophy (SMA) is a neuromuscular disorder that results in progressive muscle weakness with onset in childhood and adolescence. There are three main types of SMA. Drug treatment for SMA type I is discussed in a separate Cochrane review. This review is of drug treatment for SMA types II and III. Both of these reviews were first published in 2009 and are now updated. The age of onset of SMA type II is between six and 18 months. Children with SMA type II will never be able to walk without support; they survive beyond two years and may live into adolescence or longer. The age of onset of SMA III, also known as Kugelberg‐Welander disease, is after 18 months. Children with SMA type III develop the ability to walk at some time and their life expectancy is normal. From six randomised controlled trials, there is no evidence for a significant effect on the disease course when patients with SMA types II and III are treated with creatine (55 participants), phenylbutyrate (107 participants), gabapentin (84 participants), thyrotropin releasing hormone (9 participants), hydroxyurea (57 participants) or combination therapy with valproate and acetyl‐L‐carnitine (61 participants). The risk of bias of the included trials was systematically analysed and none of the studies were completely free of bias. Thus, there is still no known efficacious drug treatment for SMA types II and III.
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Figures

  • Active vs. inactive muscle.
    Muscular atrophy.

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