Muscular dystrophy is a group of inherited disorders that involve muscle weakness and loss of muscle tissue, which get worse over time.
Inherited myopathy, MD
Causes, incidence, and risk factors
Muscular dystrophies, or MD, are a group of inherited conditions, which means they are passed down through families. They may occur in childhood or adulthood. There are many different types of muscular dystrophy. They include:
- Becker muscular dystrophy
- Duchenne muscular dystrophy
- Emery-Dreifuss muscular dystrophy
- Facioscapulohumeral muscular dystrophy
- Limb-girdle muscular dystrophy
- Myotonia congenita
- Myotonic dystrophy
Symptoms vary with the different types of muscular dystrophy.
All of the muscles may be affected. Or, only specific groups of muscles may be affected, such as those around the pelvis, shoulder, or face. Muscular dystrophy can affect adults, but the more severe forms tend to occur in early childhood.
- Mental retardation (only present in some types of the condition)
- Muscle weakness that slowly gets worse
Signs and tests
A physical examination and your medical history will help the doctor determine the type of muscular dystrophy. Specific muscle groups are affected by different types of muscular dystrophy.
The doctor's exam may show:
- Abnormally curved spine (scoliosis)
- Joint contractures (clubfoot, clawhand, or others)
- Low muscle tone (hypotonia)
Some types of muscular dystrophy involve the heart muscle, causing cardiomyopathy or disturbed heart rhythm (arrhythmias).
Often, there is a loss of muscle mass (wasting), which may be hard to see because some types of muscular dystrophy cause a buildup of fat and connective tissue that makes the muscle appear larger. This is called pseudohypertrophy.
A muscle biopsy may be used to confirm the diagnosis. In some cases, a DNA blood test may be all that is needed.
Other tests may include:
- Heart testing - electrocardiography (ECG)
- Nerve testing - electromyography (EMG)
- Blood testing - including CPK level
- Genetic testing for some forms of muscular dystrophy
This disease may also alter the results of the following tests:
- Myoglobin - urine and blood
There are no known cures for the various muscular dystrophies. The goal of treatment is to control symptoms.
Physical therapy may help patients maintain muscle strength and function. Orthopedic appliances such as braces and wheelchairs can improve mobility and self-care abilities. In some cases, surgery on the spine or legs may help improve function.
Corticosteroids taken by mouth are sometimes prescribed to children to keep them walking for as long as possible.
The person should be as active as possible. Complete inactivity (such as bedrest) can make the disease worse.
You can ease the stress of illness by joining support groups where members share common experiences and problems.
See: Muscular dystrophy - support group
The severity of disability depends on the type of muscular dystrophy. All types of muscular dystrophy slowly get worse, but how fast this happens varies widely.
Some types of muscular dystrophy, such as Duchenne muscular dystrophy, are deadly. Other types cause little disability and people with them have a normal lifespan.
- Cardiomyopathy with heart failure
- Decreased ability to care for self
- Decreased movement
- Lung failure
- Tightening of muscles around the joints (contractures)
- Mental impairment (varies)
Calling your health care provider
Call your health care provider if:
- You have symptoms of muscular dystrophy.
- You have a personal or family history of muscular dystrophy and you are planning to have children.
Genetic counseling is advised when there is a family history of muscular dystrophy. Women may have no symptoms but still carry the gene for the disorder. Duchenne muscular dystrophy can be detected with about 95% accuracy by genetic studies performed during pregnancy.
Sarnat HB. Muscular dystrophies. In: Kliegman RM, Behrman RE, Jenson HB, Stanton BF, eds. Nelson Textbook of Pediatrics. 19th ed. Philadelphia, Pa: Saunders Elsevier; 2011:chap 601.Bushby RF, Birnkrant DJ, Case LE, Clemens PR, Cripe L, Kaul A, et al. Diagnosis and management of Duchenne muscular dystrophy. Lancet Neurol. 2010;9:77-93.
Last reviewed 2/1/2012 by Neil K. Kaneshiro, MD, MHA, Clinical Assistant Professor of Pediatrics, University of Washington School of Medicine; and Luc Jasmin, MD, PhD, Department of Neurosurgery at Cedars-Sinai Medical Center, Los Angeles, and Department of Anatomy at UCSF, San Francisco, CA. Review provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M. Healthcare Solutions, Ebix, Inc.
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