�Diseases, Conditions and Injuries

Muscular Dystrophy

En Espa�ol (Spanish Version)

Definition

Muscular dystrophy is a group of inherited, progressive muscle disorders. All forms of muscular dystrophy cause progressive weakness and degeneration of the muscles that control movement. Some also affect the heart muscle or other organs. Age of onset is between infancy to late teens. The most common form is called Duchenne dystrophy. Other forms include Becker (a milder form than Duchenne) and myotonic muscular dystrophy.

Causes

Muscular dystrophy is an inherited condition that is caused by defects in genes that are passed from parent to child.

Risk Factors

A risk factor is something that increases your chances of getting a disease or condition.

Family member with muscular dystrophy
Sex: Male

Symptoms

Symptoms common to all forms of muscular dystrophy may include:

Initial symptoms

Progressive weakening of muscles
Enlargement of muscles as they weaken
Clumsiness
Frequent falling and difficulty getting up

Later symptoms

Severe muscle deterioration, usually leading to use of a wheelchair
Distortion of the body
Muscle contraction and stiffening (often severe)

Symptoms specific to Duchenne and Becker dystrophy include:

Abnormally curved spine
Enlargement and weakening of the heart muscle
Pneumonia and other respiratory infections

Symptoms specific to myotonic muscular dystrophy can include:

Difficulty in letting go after a handshake
Muscle weakness that affects the central nervous system, heart, digestive tract, glands, or eyes

Symptoms usually become progressively worse. In many forms, life expectancy is shortened.

Diagnosis

The doctor will ask about your symptoms and medical history, and perform a physical exam.

Tests may include:
Muscle Tissue Biopsy -- removal of a sample of muscle tissue for testing
Blood Enzyme Tests -- testing a blood sample to look for elevated enzyme levels
Electromyogram (EMG) -- measures electrical impulses coming from muscles
Nerve Conduction Study (NCV) -- measures electrical impulses in the nerves

Treatment

There is no cure for muscular dystrophy. However treatment may help improve the symptoms.

Treatment may consist of:

Physical Therapy and Exercise

Physical therapy and exercise can help prevent the muscles from permanently contracting and stiffening.

Braces

In earlier stages, wearing braces on your limbs may improve your ability to move around without using a wheelchair. A back brace may retard curvature of the spine.

Medication

Medications may include:

Corticosteroids to relieve muscle weakness
Drugs for heart problems if muscular dystrophy affects the heart

Surgery

In severe cases, surgery may be required to release muscles that are painfully tight. If heart problems are involved, a pacemaker may be surgically implanted.

Prevention

Muscular dystrophy is an inherited disease. Seek genetic counseling if you are concerned about having a child with muscular dystrophy, especially if:

You have muscular dystrophy
You may be a carrier of the gene for muscular dystrophy
You are your partner have a family history of the disease

RESOURCES:

Muscular Dystrophy Association
http://www.mdausa.org

Muscular Dystrophy Family Foundation
http://www.mdff.org

REFERENCES:

The Merck Manual of Medical Information, 17th ed. Simon and Schuster, Inc.; 2000.

Muscular Dystrophy Association

National Institute of Neurological Disorders and Stroke

Last reviewed September 2005 by David Horn, MD, FACP

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