Nysha Recent News

In the Know - All About Muscular Dystrophy

Muscular dystrophy

 

Introduction

Muscular dystrophy is a group of at least 30 related genetic diseases that cause progressive weakness and loss of muscle mass.  In muscular dystrophy, genetic mutations interfere with the production of proteins needed to form healthy muscle.

 

There are many different kinds of muscular dystrophy.  Symptoms of Duchenne muscular dystrophy (DMD), the most common variety, begin in childhood, primarily in boys.  Other types don’t surface until adulthood.

 

After Duchenne, the most common forms of muscular dystrophy are Becker muscular dystrophy, myotonic dystrophy (Steinert’s disease), facioscapulohumeral dystrophy (FSHD), congenital dystrophy, and limb-girdle dystrophy.

 

Some people with muscular dystrophy will eventually lose the ability to walk.  Some may have trouble breathing or swallowing.

 

Tragically, there is no current cure for muscular dystrophy, but medications and physical and occupational therapy can help manage symptoms and slow the course of the disease.

 

Definition and symptoms

Definition and symptoms of muscular dystrophy depend on the type. 

 

The main symptom of muscular dystrophy is progressive muscle weakness.  Specific signs and symptoms begin at different ages and in different muscle groups, depending on the type.

 

Duchenne muscular dystrophy (DMD)

About half of people with muscular dystrophy have this variety.  Although girls can be carriers and mildly affected, Duchenne typically affects boys.

 

About one-third of boys with Duchenne don’t have a family history, possibly because the gene involved may be subject to sudden abnormal change (spontaneous mutation).

 

Duchenne symptoms typically appear between the ages of two and three.  They typically include:

  • Frequent falls

  • Difficulty getting up from a lying or sitting position

  • Trouble running and jumping

  • Waddling gait

  • Walking on the toes

  • Large calf muscles

  • Muscle pain and stiffness

  • Learning disabilities

 

Becker muscular dystrophy

Symptoms are similar to those of Duchenne, but are typically are milder and progress slower.  Symptoms generally begin in the teens but may not occur until the mid-20s or even later.

 

Myotonic dystrophy (Steinert’s disease)

Steinert’s is characterized by an inability to relax muscles at will following contractions.  Steinert’s is the most common form of adult-onset muscular dystrophy.  Facial and neck muscles are usually the first to be affected.

 

Facioscapulohumeral dystrophy (FSHD)

Muscle weakness typically begins in the face and shoulders.  The shoulder blades might stick out like wings when a person with FSHD raises his or her arms.  Onset usually occurs in the teenage years but may begin in childhood or as late as age 40.

 

Congenital

Congenital dystrophy affects boys and girls and is apparent at birth or before age two.  Some forms progress slowly and cause only mild disability, while others progress rapidly and cause severe impairment.

 

Limb-girdle

In limb-girdle dystrophy, hip and shoulder muscles are usually the first affected.  People with this form may have difficulty lifting the front part of the foot and so may trip frequently.  Onset usually begins in childhood or the teenage years.

 

Complications

The complications of progressive muscle weakness include:

  • Inability to walk. Some people with muscular dystrophy eventually need to use a wheelchair.

  • Shortening of muscles or tendons around joints (contractures). Contractures can further limit mobility.

  • Breathing problems. Progressive weakness can affect the muscles associated with breathing (the diaphragm and the intercostal muscles). People with muscular dystrophy may eventually need to use a breathing assistance device (ventilator), initially at night but possibly also in the day.

  • Curved spine (scoliosis). Weakened muscles may be unable to hold the spine straight.

  • Heart problems. Muscular dystrophy can reduce the efficiency of the heart muscle.

  • Swallowing problems. If the muscles involved with swallowing are affected, nutritional problems and aspiration pneumonia may develop. Feeding tubes may be an option.

 

Diagnosis

See a doctor if signs of muscle weakness are seen in a child, like increased clumsiness, falls and/or waddling gait.

 

The doctor is likely to start with a medical history and physical examination.  After that, the doctor may recommend:

  • Enzyme tests.  Damaged muscles release enzymes, such as creatine kinase (CK), into the bloodstream.  In a person who hasn’t had a traumatic injury, high blood levels of CK suggest a muscle disease—such as muscular dystrophy.

  • Electromyography.  An electrode needle is inserted into the muscle to be tested.  Electrical activity of the muscle fibers is measured as the patient relaxes and then gently tightens the muscle.  Changes in the pattern of electrical activity can confirm a muscle disease.

  • Genetic testing.  Blood samples can be examined for mutations in some of the genes that cause different types of muscular dystrophy.

  • Muscle biopsy.  A small piece of muscle can be removed through an incision or with a hollow needle.  Analysis (biopsy) of the tissue sample can distinguish muscular dystrophies from other muscle diseases.

  • Heart-monitoring tests (electrocardiography and echocardiogram).  These tests are used to check heart function, especially in people diagnosed with myotonic muscular dystrophy.

  • Lung-monitoring tests.  These tests are used to check lung function (pulmonary function testing and vital capacity measurement).

 

Cause

Certain genes are involved in making proteins that protect muscle fibers from damage.  Muscular dystrophy occurs when one of these genes is defective.

 

Each form of muscular dystrophy is caused by a genetic mutation particular to that type of the disease.  Many of these mutations are inherited.  But some occur spontaneously before birth and can be passed on to the next generation.

 

People with a family history of muscular dystrophy are at higher risk of developing the disease or passing it on to their children.

 

Treatment

Unfortunately, there are no specific treatments or cures today that stops or reverses any form of this genetic disorder.  But treatment can help prevent or reduce problems in the joints and spine to allow people with muscular dystrophy to remain mobile as long as possible.

 

Treatment options include: medications, physical/occupational/speech therapy and assistive devices, and surgical and other procedures. 

 

Proper nutrition is also a vital part of any long-term muscular dystrophy treatment plan.

 

Medications

  • Corticosteroids, such as prednisone, which can help improve muscle strength and delay the progression of certain types of muscular dystrophy.  But prolonged use of these types of drugs can cause weight gain and weaken bones, increasing fracture risk.

  • Heart medications like as angiotensin-converting enzyme (ACE) inhibitors or beta blockers may be prescribed if muscular dystrophy damages the heart muscle.

  • Anticonvulsants may be prescribed to control seizures and some muscle activity.

  • Immunosuppressants may be prescribed to delay some damage to dying muscle cells.

  • Antibiotics may be used as needed to fight respiratory infections.

  • Because respiratory infections may become a problem in later stages of muscular dystrophy, it’s important for patients to be vaccinated for pneumonia and the latest flu strains.

 

Therapy

Physical, occupational, and/or speech therapy, along with assistive devices as necessary, can improve quality and sometimes length of life in people with muscular dystrophy, including:

  • Range-of-motion and stretching exercises.  Muscular dystrophy can restrict the flexibility and mobility of joints.  Limbs often draw inward and become fixed in that position.  Range-of-motion exercises can help to keep joints as flexible as possible.

  • Exercise.  Low-impact aerobic exercise, such as walking and swimming, can help maintain strength, mobility and general health.  Some types of strengthening exercises also might be helpful.  But it’s important to talk to the doctor first because some types of exercise might be harmful.

  • Braces.  Braces can help keep muscles and tendons stretched and flexible, slowing the progression of contractures.  Braces can also aid mobility by providing support for weakened muscles.

  • Mobility aids.  Canes, walkers and wheelchairs can help maintain mobility and independence.

  • Breathing assistance.  As respiratory muscles weaken, a sleep apnea device may help improve oxygen delivery during the night.  Some people with severe muscular dystrophy may need to use a ventilator, a machine that forces air in and out of the lungs.

 

Surgery

Surgery may be needed to correct a spinal curvature that could eventually make breathing more difficult. Spinal contractures may be helped with surgery as well.

 

Nutrition

Dietary changes haven’t been shown to slow the progression of muscular dystrophy.  But proper nutrition is essential because limited mobility can contribute to obesity, dehydration and constipation.  A high-fiber, high-protein, low-calorie diet may help.

 

Prognosis

The prognosis for people with muscular dystrophy varies according to the type and progression.  Some cases may be mild and progress very slowly over a normal lifespan, while others produce severe muscle weakness, functional disability, and loss of the ability to walk.  There is no cure.

 

A prognosis of muscular dystrophy can be extremely challenging. To cope, patients should:

  • Find someone to talk with.  A patient may feel comfortable discussing your feelings with a friend or family member, or might prefer meeting with a formal support group.

  • Learn to discuss a child’s condition. If a child has muscular dystrophy, ask your doctor about the most appropriate ways to discuss the progressive condition with him or her.

 

Hamaspik thanks Eli S. Neiman, DO, ABONP, FACN, PC of the Airmont, New York-based Advanced Neurology Center for critically reviewing this article.