Muscular Dystrophy

What is muscular dystrophy?

Muscular dystrophy (MD) is a group of inherited diseases that cause the muscles to weaken and degenerate. The muscles lack a key protein needed to work properly. The body loses muscle tissue and replaces it with fat and connective tissue. This can make the muscles look larger than normal. Despite the size of the muscles, children with muscular dystrophy have significant muscle weakness which makes walking difficult or even impossible. Currently, there is no cure.

There are many forms of muscular dystrophy. Duchenne muscular dystrophy is the most common type and the most severe childhood form of the disease. It usually begins before the age of 5 and affects mostly boys. The life span for people with MD is usually shortened.

How does it occur?

MD is a genetic disorder. This means that a child with MD has one or more defective muscle genes. The genes normally make a muscle protein, but when a child has MD, a protein may not work properly. Sometimes no protein at all is made. One or both parents may be a carrier of the gene and pass it on to their child, depending on the type of MD. A carrier is a person who carries the faulty gene that causes MD, but who usually shows no symptoms of MD.

What are the symptoms?

All types of muscular dystrophy cause muscle weakness and lack of coordination. Signs of muscular dystrophy are often noticed when a child is very young. A child may appear clumsy and have a tendency to fall a lot.

A child with Duchenne MD may also have:

• difficulty getting up from the ground
• an unusual, waddling gait
• enlargement of the calf and other muscles.

Symptoms of muscle weakness may be found in many other serious conditions. So, it is important to consult with your healthcare provider as soon as you notice that your child has muscle weakness.

How is it diagnosed?

Blood tests are done to check for MD. Children with MD usually have high levels of creatine kinase, a muscle enzyme, in their blood. Other tests may include studying a small piece of muscle, called a muscle biopsy, or a test of muscle and nerve function.

How does MD progress?

The course of the disease is fairly predictable for children with Duchenne MD. The child will begin having difficulty between 3 and 5 years of age with climbing stairs and getting off the ground. A wheelchair is usually needed by age 12. In most cases, the children develop tightness around the joints of their hips, knees, and ankles and can have a curved spine. Breathing problems and respiratory infections occur as the muscle weakness gets worse.

The heart is affected in many types of muscular dystrophy. As the breathing muscles weaken, lung problems, including pneumonia, may develop.

How is it treated?

Although there is no cure, symptoms of muscular dystrophy can be reduced by:

• exercise programs and physical therapy to minimize muscle shortening around the joints
• assistive aids, such as walkers, manual and electric wheelchairs to maintain mobility
• surgery to relieve muscle shortening and curvature of the spine.

Medicine used to treat muscular dystrophy may include:

• corticosteroids to slow muscle degeneration
• anticonvulsants to control seizures
• immunosuppressants to slow damage to muscle cells
• antibiotics to fight lung infections.

If breathing becomes difficult, mechanical ventilation devices can be used to help, especially at night.

Many experimental therapies have not yet shown proven benefits. However, there is a great deal of medical research going on to find better treatments and perhaps someday, a cure for this disease.

Can a special diet help my child?

When people hear that muscular dystrophy means an abnormal protein, they wonder if they should eat more protein. Unfortunately, eating more protein does not make muscular dystrophy better.

Special diets or supplements do not help muscular dystrophy. A diet similar to that for any growing boy is recommended, with some changes. The diet should be high in fluid and fiber, with lots of fresh fruits and vegetables to prevent severe constipation. Those on prednisone and those with heart problems also may need to cut back on sodium in the diet. Boys who use power wheelchairs, take prednisone, or who aren't very active, should follow a low-calorie diet to keep weight down. Being overweight can stress weakened muscles and the heart. A low-calorie diet does not harm the muscles.

Where can I get more information?

The Muscular Dystrophy Association provides counseling, support, services, and research. Go to their Web site at http://www.mdausa.org or contact your local chapter for more information.