What is muscular dystrophy?Muscular dystrophy (MD) is a broad term that describes a genetic (inherited) disorder of the muscles. Muscular dystrophy causes the muscles in the body to become very weak. The muscles break down and are replaced with fatty deposits over time.
Other health problems commonly associated with muscular dystrophy include the following:
- heart problems
- scoliosis - a lateral, or sideways, curvature and rotation of the back bones (vertebrae), giving the appearance that the person is leaning to one side.
What causes muscular dystrophy?Duchenne muscular dystrophy is a genetic disease which means it is inherited. Our genes determine our traits, such as eye color and blood type. Genes are contained in the cells of our bodies on stick-like structures called chromosomes. There are normally 46 chromosomes in each cell of our body, or 23 pairs. The first 22 pairs are shared in common between males and females, while the last pair determine gender and are called the sex chromosome pair: females have two X chromosomes, while males have one X and one Y chromosome.
Duchenne muscular dystrophy is caused by an X-linked recessive gene. "X-linked" means that the gene causing the trait or the disorder is located on the X chromosome. Genes on the X chromosome can be recessive or dominant, and their expression in females and males is not the same because the genes on the Y chromosome do not exactly pair up with the genes on the X. X-linked recessive genes are expressed in females only if there are two copies of the gene (one on each X chromosome). However, for males there only needs to be one copy of an X-linked recessive gene in order for the trait or disorder to be expressed. For example, a woman can carry a recessive gene on one of the X chromosomes unknowingly, and pass it on to a son, who will express the trait or disease.
What are the symptoms of muscular dystrophy?Muscular dystrophy is usually diagnosed in children between 3 and 6 years of age. Early signs of the illness include a delay in walking, difficulty rising from a sitting or lying position, and frequent falling, with weakness typically affecting the shoulder and pelvic muscle as one of the initial symptoms. The following are the most common symptoms of muscular dystrophy. However, each child may experience symptoms differently. Symptoms may include:
- clumsy movement
- difficulty climbing stairs
- frequently trips and falls
- unable to jump or hop normally
- tip toe walking
- leg pain
- facial weakness
- inability to close eyes or whistle
- shoulder and arm weakness
Another classic symptom of muscular dystrophy is known as the "slip through" symptom. Your child's physician puts his/her hands around the sides of the child's chest, right up under the arms. As the child is lifted up, the shoulders weaken and move upward, almost allowing the child to slip through your child's physician's hands.
In addition, children with muscular dystrophy often have very large calf muscles due to the large amounts of fatty deposits that are replacing muscle.
The symptoms of muscular dystrophy may resemble other conditions or medical problems. Always consult your child's physician for a diagnosis.
How is muscular dystrophy diagnosed?The diagnosis of muscular dystrophy is made with a physical examination and diagnostic testing by your child's physician. During the examination, your child's physician obtains a complete prenatal and birth history of the child and asks if other family members are known to have muscular dystrophy.
Diagnostic tests for muscular dystrophy may include:
- blood tests
- muscle biopsy - the primary test used to confirm diagnosis. A small sample of muscle tissue is taken and examined under a microscope.
- electromyogram (EMG) - test to check if the muscle weakness is a result of destruction of muscle tissue rather than nerve damage.
- electrocardiogram (ECG or EKG) - a test that records the electrical activity of the heart, shows abnormal rhythms (arrhythmias or dysrhythmias), and detects heart muscle damage.
Treatment for muscular dystrophy:Specific treatment for muscular dystrophy will be determined by your child's physician based on:
- your child's age, overall health, and medical history
- the extent of the condition
- the type of condition
- your child's tolerance for specific medications, procedures, or therapies
- expectations for the course of the condition
- your opinion or preference
Since muscular dystrophy is a life-long condition that is not correctable, management includes focusing on preventing or minimizing deformities and maximizing the child's functional ability at home and in the community.
Management of muscular dystrophy is either non-surgical or surgical. Non-surgical interventions may include:
- physical therapy
- positioning aids - used to help the child sit, lie, or stand
- braces and splints - used to prevent deformity, promote support, or provide protection
- nutritional counseling
- psychological counseling
- scoliosis (a sideways curvature of the back bones) associated with muscular dystrophy
- maintaining the child's ability to sit or stand
Long-term outlook for a child with muscular dystrophy:Muscular dystrophy is a progressive condition that needs life-long management to prevent deformity and complications. Walking and sitting often becomes more difficult as the child grows. Usually by the age of 12, the child needs a wheelchair because the leg muscles are too weak to work. Heart or lung problems often occur by the late teenage years or into the early 20s.
The interdisciplinary healthcare team will work with your family to improve your child's functional outcomes and to provide support as you learn to care for your child's needs.
The Muscular Dystrophy Association (MDA) can be an important resource, both financially and emotionally, for parents of children with muscular dystrophy.
The information on this Web page is provided for educational purposes. You understand and agree that this information is not intended to be, and should not be used as, a substitute for medical treatment by a health care professional. You agree that Lucile Salter Packard Children's Hospital is not making a diagnosis of your condition or a recommendation about the course of treatment for your particular circumstances through the use of this Web page. You agree to be solely responsible for your use of this Web page and the information contained on this page. Lucile Salter Packard Children's Hospital, its officers, directors, employees, agents, and information providers shall not be liable for any damages you may suffer or cause through your use of this page even if advised of the possibility of such damages.