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Description:
The term muscular dystrophy refers to a
group of disorders characterized by progressive muscle weakness and loss of
muscle tissue. Muscular dystrophy includes many inherited disorders such
as:
-
Becker's muscular dystrophy (slowly
progressive form of MD; affects legs and pelvis most severely)
-
Duchenne's muscular dystrophy
(similar to Becker's, but progresses more rapidly)
-
Facioscapulohumeral muscular
dystrophy (mild, slowly progressive form; face, shoulders, and upper arms
affected)
-
Limb-girdle muscular
dystrophy
Disorders are distinguished by the type
of inheritance (dominant genes, recessive gene, and so on), the age when
symptoms appear, and the types of symptoms that develop. Because these are
inherited disorders, risks include a family history of muscular dystrophy.
Symptoms:
Diagnosis:
Examination and history help to
distinguish the type of MD. Specific muscle groups are affected by different
types of MD. There often is a loss of muscle mass (wasting), which may be
disguised in some types of muscular dystrophy by an accumulation of fat and
connective tissue (pseudohypertrophy). Muscle contractures are common, which
involve the inability to use the muscle because of shortening of the muscle
fibers and fibrosis of the connective tissue. Some types of MD involve the heart
muscle, causing irregular or inadequate heart pumping. Other points of
note include:
-
A muscle biopsy is the primary test
used to confirm the diagnosis.
-
A serum CPK (muscle enzyme) may be
elevated.
-
An EMG (electromyography) may confirm
that weakness is caused by destruction of muscle tissue rather than damage to
nerves.
Treatment:
There is no known cure for
muscular dystrophy. Treatment is aimed at controlling symptoms to maximize the
quality of life. Activity is encouraged to the degree tolerated. Inactivity
(such as bedrest) can worsen the muscle disease. Physical therapy may be helpful
to maintain muscle strength and functioning. Orthopedic appliances such as
braces and wheelchairs may improve mobility and self-care
abilities.
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