Muscular Dystrophy

According to the Mayo Clinic Muscular dystrophy (MD) is a group of inherited muscle diseases in which muscle fibers are unusually susceptible to damage. Muscles, primarily voluntary muscles, become progressively weaker. In the late stages of muscular dystrophy, fat and connective tissue often replace muscle fibers. Some types of muscular dystrophy affect heart muscles, other involuntary muscles and other organs.

The most common types of muscular dystrophy appear to be due to a genetic deficiency of the muscle protein dystrophin.

There's no cure for muscular dystrophy, but medications and therapy can slow the course of the disease.
Signs and symptoms vary according to the type of muscular dystrophy. In general, muscular dystrophy symptoms may include:

Muscle weakness
Apparent lack of coordination
Progressive crippling, resulting in fixations (contractures) of the muscles around your joints and loss of mobility
Specific signs and symptoms vary among the different forms of MD. Each type is different in the age of onset, which parts of the body the symptoms primarily affect and how rapidly the disease progresses.

Dystrophinopathies
These types of muscular dystrophies are due to a genetic defect of the protein dystrophin.

Duchenne's muscular dystrophy is the most severe form of dystrophinopathy. It occurs mostly in young boys and is the most common form of MD that affects children. Signs and symptoms of Duchenne's MD may include:

Frequent falls
Large calf muscles
Difficulty getting up from a lying or sitting position
Weakness in lower leg muscles, resulting in difficulty running and jumping
Waddling gait
Mild mental retardation, in some cases
Signs and symptoms of Duchenne's usually appear between the ages of 2 and 3. It first affects the muscles of the pelvis, upper arms and upper legs. By late childhood, most children with this form of muscular dystrophy are unable to walk. Most die by their 20s or early 30s, often from pneumonia, respiratory muscle weakness or cardiac complications. Some people with Duchenne's MD may exhibit curvature of their spine (scoliosis).

Becker's muscular dystrophy is a milder form of dystrophinopathy. It generally affects older boys and young men, and progresses more slowly, usually over several decades. Signs and symptoms of Becker's MD are similar to those of Duchenne's. The onset of the signs and symptoms is generally around age 11, but may not occur until the mid-20s or even later. Those affected by Becker's MD usually are able to walk through their teens, and often well into adulthood.

Myotonic dystrophy
Also known as Steinert's disease, this form of muscular dystrophy produces stiffness of muscles and an inability to relax muscles at will (myotonia), as well as the muscle weakness of the other forms of muscular dystrophy.

Although this form of MD can affect children, it often doesn't affect people until adulthood. It can vary greatly in its severity. Muscles may feel stiff after using them. Progression of this form of MD is slow. Besides myotonia, signs and symptoms of adult-onset myotonic dystrophy may include:

Weakening of voluntary muscles that control your arms and legs, usually beginning with the limb muscles farthest from the torso — the muscles of the feet, hands, lower legs and forearms.
Weakening of head, neck and face muscles, which may result in the face having a hollow, drooped appearance.
Weakening of muscles involved in breathing and swallowing. Weaker breathing muscles may result in less oxygen intake and fatigue. Weaker swallowing muscles increase the risk of choking.
Fainting or dizziness, which may indicate that the disease is interfering with the conduction of electrical signals that keep the heart rate normal.
Weakening of muscles of hollow internal organs such as those in the digestive tract and the uterus. Depending on which part of the digestive tract is affected, you may experience problems with swallowing as well as constipation and diarrhea. Weakness of the uterine walls may cause problems during childbirth.
Difficulty sleeping well at night and daytime sleepiness, and inability to concentrate because of the effect of the disease on the brain.
Frontal balding in men.
Clouding of the lenses of the eyes (cataracts).
Mild diabetes.
Rarely, infants have this form of muscular dystrophy, in which case it's called congenital myotonic dystrophy. The infant form is more severe, although infants with myotonic dystrophy don't experience myotonia. Signs in infants may include:

Severe muscle weakness
Difficulty sucking and swallowing
Difficulty breathing
Cognitive impairment
Facioscapulohumeral muscular dystrophy
Also known as Landouzy-Dejerine dystrophy, this form involves progressive muscle weakness involving:

Face
Shoulders
Abdomen
Feet
Upper arms
Pelvic area
Lower arms
When someone with facioscapulohumeral MD raises his or her arms, the shoulder blades may stick out like wings. Progression of this form is slow, with some spurts of rapidly increasing weakness. Onset usually occurs during the teen to early adult years.

Other major types of muscular dystrophy
The other major types of muscular dystrophy include:

Limb-girdle muscular dystrophy
Congenital muscular dystrophy
Oculopharyngeal muscular dystrophy
Distal muscular dystrophy
Emery-Dreifuss muscular dystrophy
Myofibrillar myopathies
Limb-girdle muscular dystrophy
Muscles usually affected first by this form of muscular dystrophy include:

Hips
Shoulders
This form then progresses to the arms and legs, though progression is slow. Limb-girdle MD may begin from early childhood to adulthood.

Congenital muscular dystrophy
The term "congenital muscular dystrophy" refers to a group of inherited muscular dystrophies. Signs of these disorders may include:

General muscle weakness
Joint deformities
Congenital MD is apparent at birth or becomes evident before age 2. The course of this disorder varies significantly depending on the type. Some forms of congenital MD progress slowly and cause only mild disability, while others progress rapidly and cause severe impairment.

Oculopharyngeal muscular dystrophy
The first sign of this type of muscular dystrophy is usually drooping of the eyelids, followed by weakness of the muscles of the eye, face and throat, resulting in difficulty swallowing. Progression is slow. Signs and symptoms first appear in adulthood, usually in a person's 40s or 50s.

Distal muscular dystrophy
This group involves the muscles farthest away from the center of the body (distal muscles) — those of the hands, forearms, feet and lower legs. The severity is generally less than for other forms of MD, and this form tends to progress slowly. Distal MD generally begins in adulthood between the ages of 40 and 60.

Emery-Dreifuss muscular dystrophy
This form of muscular dystrophy usually begins in the muscles of the:

Shoulders
Upper arms
Shins
Cardiac arrhythmias, stiffness of the spine and muscle contractures are other features of Emery-Dreifuss MD. Emery-Dreifuss MD usually begins in the childhood to early teen years and progresses slowly.

Myofibrillar myopathies (MFMs)
Though in some cases the MFMs affect only the muscles closest to the center of the body (proximal muscles) — such as the shoulder and hip muscles — the distal muscles also are usually involved. This group of muscle disorders also is commonly associated with:

Stiffness of the spine
Muscle contractures
Nerve damage (peripheral neuropathy)
Thickening and stiffening of the heart muscle (cardiomyopathy)
When to see a doctor
Duchenne's muscular dystrophy occurs almost exclusively in boys, although it can occur in girls. Your young child may have difficulty walking, running, rising from the floor or climbing the stairs, or may appear clumsy and fall often. These may be early indications of muscular dystrophy.

A child with MD may learn to walk later than other children do and may exhibit signs of muscle weakness between the ages of 2 and 6. By school age, a child with MD may walk unsteadily and on the toes or balls of the feet. Duchenne's MD usually results in children losing the ability to walk by age 12.

See your doctor if you're concerned about your child's:

Motor abilities
Clumsiness
Muscle strength
Muscle development
Once muscular dystrophy is diagnosed, medications and physical therapy can help slow its progression.

Because muscular dystrophies are inherited disorders, genetic counseling may be helpful if you're considering having children and to assess the risk of the disease in other family members.
There's currently no cure for any form of muscular dystrophy. Research into gene therapy may eventually provide treatment to stop the progression of some types of muscular dystrophy. Current treatment is designed to help prevent or reduce deformities in the joints and the spine and to allow people with MD to remain mobile as long as possible. Treatments may include various types of physical therapy, medications, assistive devices and surgery.

Physical therapy
As muscular dystrophy progresses and muscles weaken, fixations (contractures) can develop in joints. Tendons can shorten, restricting the flexibility and mobility of joints. Contractures are uncomfortable and may affect the joints of your hands, feet, elbows, knees and hips.

One goal of physical therapy is to provide regular range-of-motion exercises to keep your joints as flexible as possible, delaying the progression of contractures, and reducing or delaying curvature of your spine. Using hot baths (hydrotherapy) also can help maintain range of motion in joints.

Medications
In some cases, doctors may prescribe medications to slow the progression and manage signs and symptoms of muscular dystrophy:

Muscle spasms, stiffness and weakness (myotonia). Medications that may be used to help manage myotonia associated with MD include mexiletine (Mexitil), phenytoin (Dilantin, Phenytek), baclofen (Lioresal), dantrolene (Dantrium) and carbamazepine (Tegretol, Carbatrol).
Muscle deterioration. The anti-inflammatory corticosteroid medication prednisone may help improve muscle strength and delay the progression of Duchenne's MD. The immunosuppressive drugs cyclosporin and azathioprine also are sometimes prescribed to delay some damage to dying muscle cells.
Assistive devices
Braces can both provide support for weakened muscles of your hands and lower legs and help keep muscles and tendons stretched and flexible, slowing the progression of contractures. Other devices, such as canes, walkers and wheelchairs, can help maintain mobility and independence. If respiratory muscles become weakened, using a ventilator may become necessary.

Surgery
To release the contractures that may develop and that can position joints in painful ways, doctors can perform a tendon release surgery. This may be done to relieve tendons of your hip and knee and on the Achilles tendon at the back of your foot. Surgery may also be needed to correct curvature of the spine.

Other treatments
Because respiratory infections may become a problem in later stages of muscular dystrophy, it's important to be vaccinated for pneumonia and to keep up to date with influenza shots.
Jerry's Kids, the most famous of the support and fund raising, awareness raising groups can be found online at http://www.mda.org/
To learn more, look for a local support group in your area.

Aimee Boyle is a freelance writer in Southern CT. She contributes regularly to EmpowHer, writing about sexuality and muscles.

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