Muscular dystrophy (MD) is a group of diseases that weaken the muscles, and as time goes by the condition gets worse. It is caused by genetic mutations. The most prevalent form of the illness in children is Duchenne muscular dystrophy (DMD). It mostly affects males. Another form of the disease that affects male children is Becker’s muscular dystrophy (BMD).
Definition & Facts
Muscular dystrophy is most often hereditary. It is a condition where the muscles gradually weaken and deteriorate over time. Genetic mutations inhibit proteins needed to form healthy muscles. According to the Centers for Disease Control and Prevention, DMD affects one in 3,500 live male births. Male children get diagnosed with DMD as early as five years old. The same statistical data indicates that BMD affects one in 18,500 live male births.
Myotonic muscular dystrophy (which is also referred to as myotonic dystrophy, MMD, and DM) is the most common form of muscular dystrophy that is diagnosed in adults. In addition to causing muscle weakening, a subtype of MMD may cause learning disabilities. There are two types of MMD: MMD1 (DM1) and MMD2 (DM2).
Symptoms & Complaints
- Falling often
- Struggling to get out of bed or to stand up if sitting down
- Having difficulties running and jumping
- Walking unsteadily due to muscle instability
- Enlarged calf muscles
- Pain and muscle stiffness
- Learning disabilities
The symptoms of Becker’s muscular dystrophy (BMD) are similar to that of DMD, but they are milder and do not develop as quickly as DMD. The signs of the condition will start to show in teenagers, but they evolve in the mid-twenties or older. Patients with myotonic muscular dystrophy - MMD - tend to develop sleep apnea in which they stop breathing for a few seconds while asleep during the night. Additional symptoms of MMD include:
- Overwhelming urge to sleep during the day
- Insufficient oxygen during sleep
- Choking while swallowing
- Developing cataracts
- Drooping eyelids
- Muscle weakness in head, neck, and face
- Early balding
- Heart problems
- Fainting or dizziness
- Developing conditions similar to diabetes such as insulin resistance
- Weakening of the digestive tract
- Developing gallstones
- Cramping, constipation, and diarrhea
- Women experiencing difficulty during childbirth
- Low blood pressure
- Muscle weakness in the hand and limb
- Muscle pain
Symptoms of MMD that first appear in children after infancy and before adolescence may include behavioral problems and cognitive impairments. They may be unable to make decisions or plan future tasks. They also have difficulties organizing visual information and making them meaningful. Moreover, children suffering from MMD tend to be very shy.
Infants with congenital MMD may have severe cognitive disabilities. The symptoms include speech problems, hearing problems, and vision problems. Babies tend to have weak muscles, and they may be born with club feet.
Genetic mutations are the cause of MD, though not all of these mutations are inherited. Some of the genetic mutations occur spontaneously in a female’s egg or the developing embryo. About one-third of male children who are affected by DMD do not have a family history of the illness. Regardless of what causes the genetic mutation, it results in the cells that hold muscle together being unable to perform. The consequence is muscle weakness.
People with MD can inherit the disease in different ways based on the particular type of MD. In cases of DMD, the genetic mutation is located on the X chromosome and is passed down through X-linked dominant inheritance which affects males more than females.
Diagnosis & Tests
- Enzyme tests. The doctor checks the blood for proteins. If the blood has high levels of creatine kinase, a type of enzyme, it indicates that the patient has a muscle disease.
- Electromyography. The doctor inserts a needle in the muscle to measure electrical activity. If the electrical activity changes the pattern, it could mean the patient has MD.
- Genetic testing. The doctor will test the patient’s blood to the see if there are any genetic mutations.
- Muscle biopsy. The doctor takes a biopsy or tissue sample by using a hollow needle to make an incision. He or she then analyzes the tissue.
- Heart-monitoring tests such as electrocardiograms (EKG). This particular test checks the electrical activity of the heart in individuals diagnosed with myotonic muscular dystrophy.
- Lung-monitoring tests. The test checks how well the lungs function.
Treatment & Therapy
MD does not have a cure, but doctors use medications, physical therapy, and surgical procedures to treat the condition. Recommended medications and therapies include:
- Corticosteroids – prednisone: Helps to slow down the progression of certain types of MD. If the patient uses the medication for extended periods of time, weight gain may occur, and bones could become weak.
- Heart medications - angiotensin-converting-enzyme (ACE) inhibitors or beta blockers: These can be used if MD damages the heart. Perindopril, an ACE inhibitor, has been shown to lower the mortality rate of people with DMD.
- Physical therapy is crucial in assisting patients with MD and may include stretching exercises and low-impact aerobic exercise.
- Orthotic devices such as leg braces.
- Mobility aids such as canes, walkers, wheelchairs.
- Breathing assistance such as inspiratory and expiratory muscle aids.
Prevention & Prophylaxis