Muscular dystrophy
Inherited myopathy; MD
Muscular dystrophy is a group of inherited disorders that cause muscle weakness and loss of muscle tissue, which get worse over time.
Muscle weakness
Weakness is reduced strength in one or more muscles.
Causes
Muscular dystrophies, or MD, are a group of inherited conditions. This 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
Becker muscular dystrophy
Becker muscular dystrophy is an inherited disorder that involves slowly worsening muscle weakness of the legs and pelvis.
-
Duchenne muscular dystrophy
Duchenne muscular dystrophy
Duchenne muscular dystrophy is an inherited disorder. It involves muscle weakness, which quickly gets worse.
- Emery-Dreifuss muscular dystrophy
-
Facioscapulohumeral muscular dystrophy
Facioscapulohumeral muscular dystrophy
Facioscapulohumeral muscular dystrophy is muscle weakness and loss of muscle tissue that gets worse over time.
- Limb-girdle muscular dystrophy
- Oculopharyngeal muscular dystrophy
Symptoms
Muscular dystrophy can affect adults, but the more severe forms tend to occur in early childhood.
Symptoms vary among 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. The muscle weakness slowly gets worse and symptoms can include:
- Delayed development of muscle motor skills
- Difficulty using 1 or more muscle groups
- Drooling
-
Eyelid drooping
(
ptosis
)
Eyelid drooping
Ptosis (eyelid drooping) in infants and children is when the upper eyelid is lower than it should be. This may occur in one or both eyes. Eyelid dr...
Ptosis
Eyelid drooping is excess sagging of the upper eylid. The edge of the upper eyelid may be lower than it should be (ptosis) or there may be excess ba...
- Frequent falls
- Loss of strength in a muscle or group of muscles as an adult
- Loss in muscle size
-
Problems walking
(delayed walking)
Problems walking
Walking abnormalities are unusual and uncontrollable walking patterns. They are usually due to diseases or injuries to the legs, feet, brain, spinal...
Intellectual disability is present in some types of muscular dystrophy.
Exams 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
)
Scoliosis
Scoliosis is an abnormal curving of the spine. Your spine is your backbone. It runs straight down your back. Everyone's spine naturally curves a b...
-
Joint contractures (
clubfoot
, clawhand, or others)
Clubfoot
Clubfoot is when the foot turns inward and downward. It is a congenital condition, which means it is present at birth.
- Low muscle tone ( hypotonia )
Some types of muscular dystrophy involve the heart muscle, causing cardiomyopathy or abnormal heart rhythm ( arrhythmia ).
Cardiomyopathy
Cardiomyopathy is disease in which the heart muscle becomes weakened, stretched, or has another structural problem. It often occurs when the heart c...
Arrhythmia
An arrhythmia is a disorder of the heart rate (pulse) or heart rhythm. The heart can beat too fast (tachycardia), too slow (bradycardia), or irregul...
Often, there is a loss of muscle mass ( wasting ). This 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.
Muscle biopsy
A muscle biopsy is the removal of a small piece of muscle tissue for examination.
Other tests may include:
- Heart testing: electrocardiography (ECG)
-
Nerve testing:
nerve conduction
and electromyography (
EMG
)
Nerve conduction
Nerve conduction velocity (NCV) is a test to see how fast electrical signals move through a nerve.
EMG
Electromyography (EMG) is a test that checks the health of the muscles and the nerves that control the muscles.
-
Urine and blood testing, including
CPK
level
CPK
Creatine phosphokinase (CPK) is an enzyme in the body. It is found mainly in the heart, brain, and skeletal muscle. This article discusses the test...
- Genetic testing for some forms of muscular dystrophy
Treatment
There are no known cures for the various muscular dystrophies. The goal of treatment is to control symptoms.
Physical therapy may help maintain muscle strength and function. Leg braces and a wheelchair can improve mobility and self-care. In some cases, surgery on the spine or legs may help improve function.
Corticosteroids taken by mouth are sometimes prescribed to children with certain muscular dystrophies to keep them walking for as long as possible.
The person should be as active as possible. No activity at all (such as bedrest) can make the disease worse.
Support Groups
You can ease the stress of illness by joining a support group where members share common experiences and problems.
Support group
The following organizations are good resources for information on muscular dystrophy:Muscular Dystrophy Association -- www. mda. orgNational Institut...
Outlook (Prognosis)
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 in boys, are deadly. Other types cause little disability and people have a normal lifespan.
When to Contact a Medical Professional
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.
Prevention
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 done during pregnancy.
References
Sarnat HB. Muscular dystrophies. In: Kliegman RM, Stanton BF, St Geme JW, Schor NF, eds. Nelson Textbook of Pediatrics . 20th ed. Philadelphia, PA: Elsevier; 2016:chap 609.
Selcen D. Muscle diseases. In: Goldman L, Schafer AI, eds. Goldman's Cecil Medicine . 25th ed. Philadelphia, PA: Elsevier Saunders; 2016:chap 421.
-
Superficial anterior muscles - illustration
Superficial muscles are close to the surface of the skin. Muscles which lie closer to bone or internal organs are called deep muscles.
Superficial anterior muscles
illustration
-
Muscular dystrophy
(Alt. Medicine)
Review Date: 2/27/2016
Reviewed By: Amit M. Shelat, DO, FACP, Attending Neurologist and Assistant Professor of Clinical Neurology, SUNY Stony Brook, School of Medicine, Stony Brook, NY. Review provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the A.D.A.M. Editorial team.