What Is Muscular Dystrophy?
Muscular dystrophy (MD) is a genetic disorder that gradually weakens the body's
muscles. It's caused by incorrect or missing genetic information that prevents the
body from making the proteins needed to build and maintain healthy muscles.
A child who is diagnosed with MD gradually loses the ability to do things like
walk, sit upright, breathe easily, and move the arms and hands. This increasing weakness
can lead to other health problems.
There are several major forms of muscular dystrophy, which can affect the muscles
to varying degrees. In some cases, MD starts causing muscle problems in infancy; in
others, symptoms don't appear until adulthood.
There is no cure for MD, but researchers are quickly learning more about how to
prevent and treat it. Doctors are also working on improving muscle and joint function
and slowing muscle deterioration so that those with MD can live as actively and independently
as possible.
What Are the First Symptoms of Muscular Dystrophy?
Many kids with muscular dystrophy follow a normal pattern of development during
their first few years of life. But in time they develop problems with movement. A
child who has MD may start to stumble, waddle, have difficulty going up stairs, and
toe walk (walk on the toes without the heels hitting the floor). A child may start
to struggle to get up from a sitting position or have a hard time pushing things,
like a wagon or a tricycle.
Kids with MD often develop enlarged calf muscles (called calf pseudohypertrophy)
as muscle tissue is destroyed and replaced by fat.
How Is Muscular Dystrophy Diagnosed?
When first suspecting that a child has muscular dystrophy, a doctor will do a physical
exam, take a family history, and ask about any problems — particularly those
affecting the muscles — that the child might be having.
In addition, the doctor may do tests to see what type of MD is involved and to
rule out other diseases that could cause the problem. These might include a blood
test to measure levels of serum creatine kinase, an enzyme that's
released into the bloodstream when muscle fibers are breaking down. High levels indicate
that something is causing muscle damage.
The doctor also may do a blood test to check the DNA for gene defects or do a muscle
biopsy. In a muscle biopsy, the doctor surgically removes a small sample of muscle
and looks at it under the microscope. The muscle cells of a person with MD have changes
in appearance and could have low levels of dystrophin, a protein
that helps muscle cells keep their shape and length.
What Are Some Types of Muscular Dystrophy?
The different types of muscular dystrophy affect different sets of muscles and
cause different degrees of muscle weakness.
- Duchenne
muscular dystrophy, the most common form of muscular dystrophy.
It gradually makes the body's muscles weaker.
- Becker
muscular dystrophy, which causes less severe symptoms than Duchenne MD.
- Myotonic dystrophy, also known as Steinert's disease, is the most common adult form of MD, although
half of all cases are diagnosed in people under 20 years old. The main
symptoms include muscle weakness, myotonia (in which the muscles have trouble relaxing
once they contract), and muscle wasting (when the muscles shrink over time).
- Limb-girdle muscular dystrophy affects boys and girls equally. Symptoms usually start when kids are between
8 and 15 years old. This form progresses slowly, affecting the pelvic, shoulder, and
back muscles. The severity of muscle weakness varies — some kids have only mild
weakness while others develop severe disabilities and as adults need to use a wheelchair.
- Facioscapulohumeral muscular dystrophy can affect both boys and girls, and the symptoms usually
first appear during the teen years. It tends to progress slowly. Muscle weakness first
develops in the face, making it difficult for a child to close the eyes, whistle,
or puff out the cheeks. The shoulder and back muscles gradually become weak, and kids
have trouble lifting objects or raising their hands overhead. Over time, the legs
and pelvic muscles also may lose strength.
Caring for a Child With MD
There's no cure for MD yet, but doctors are working to improve muscle and joint
function, and slow muscle deterioration.
If your child is diagnosed with MD, a team of medical
specialists will work with you and your family, including: a neurologist, orthopedist,
pulmonologist, physical and occupational therapist, nurse practitioner, cardiologist,
registered dietician, and a social worker.
Muscular dystrophy is often degenerative, meaning that it slowly affects more organs
and can't be reversed. So, kids may pass through different stages as it progresses
and need different kinds of treatment. During the early stages, physical therapy,
joint bracing, and medications are often used.
During the later stages, doctors may use assistive devices, such as:
- physical therapy and bracing to improve flexibility
- power wheelchairs and scooters to improve mobility
- a ventilator to support breathing
- robotics to help with routine daily tasks
Physical Therapy and Bracing
Physical therapy can help a
child maintain muscle tone and reduce the severity of joint contractures with exercises
that keep the muscles strong and the joints flexible.
A physical therapist also uses bracing to help prevent joint contractures, a stiffening
of the muscles near the joints that can make it harder to move and can lock the joints
in painful positions. By providing extra support in just the right places, bracing
can extend the time that a child with MD can walk independently.
Spinal Fusion
Many children with the Duchenne and Becker forms of MD develop severe scoliosis
— an S- or C-shaped curvature of the spine caused by back muscles that are too
weak to hold the spine upright.
Some kids with severe cases undergo spinal
fusion, a surgery that can reduce pain and lessen the curvature so a child can
sit upright and comfortably in a chair. This surgery ensures that the spine curvature
doesn't have an effect on breathing. Usually, spinal fusion surgery only requires
a short hospital stay.
Respiratory Care
Many kids with muscular dystrophy also have weakened heart and respiratory muscles.
As a result, they can't cough out phlegm and sometimes develop respiratory infections
that can quickly become serious. Good general health care and regular vaccinations
are especially important for children with muscular dystrophy to help prevent these
infections.
Assistive Devices
A variety of new
technologies can provide independence and mobility for kids with muscular dystrophy.
Some kids with Duchenne MD might use a manual wheelchair once it becomes difficult
to walk. Others go directly to a motorized wheelchair, which can be equipped to meet
their needs as muscle deterioration advances.
Robotic technologies also are under development to help kids move their arms and
perform activities of daily living.
If your child would benefit from an assistive technological device, contact your
local chapter of the Muscular Dystrophy Association
to ask about financial help that might be available. In some cases, health
insurers cover the cost of these devices.
The Search for a Cure
Researchers are quickly learning more about what causes the genetic disorder that
leads to muscular dystrophy, and about possible treatments for the disease.
To learn more about the most current research on MD, contact the local chapter
of the Muscular Dystrophy Association or talk to your doctor, who also can tell you
about clinical trials on MD.