Muscular dystrophy is a group of genetic disorders characterized by muscle weakness and progressive loss of muscle tissue. It is also commonly referred to as MD.
Muscular dystrophy is caused by an alteration in the structure of a gene that is responsible for making the proteins required for building muscles.
Muscular dystrophy commonly affects the skeletal muscles however some forms of the disorder affect the muscles of the heart, gastrointestinal tract, endocrine glands, eyes, spine and brain.
Various forms of muscular dystrophy have been identified. Some are common in children while some are seen in adults. All forms differ among themselves in severity of disease, muscles affected, age of onset, rate of progression, and family history.
The nine forms of muscular dystrophies are classified into three main groups based on the age of onset of symptoms.
Childhood Onset Muscular Dystrophies
- Duchenne muscular dystrophy
- Becker muscular dystrophy
- Congenital muscular dystrophy
- Emery-Dreifuss muscular dystrophy
Adolescent Onset Muscular Dystrophies
- Facioscapulohumeral muscular dystrophy
- Limb-girdle muscular dystrophy
Adult Onset Muscular Dystrophies
- Distal muscular dystrophy
- Myotonic muscular dystrophy
- Oculopharyngeal muscular dystrophy
Childhood-Onset Muscular Dystrophies
These forms of the disease have their symptoms apparent during childhood. The four sub-types of childhood-onset disease include Duchenne MD, Becker MD, Congenital MD, and Emery-Dreifuss MD. They share many of the same common symptoms and may vary only in age of onset, preponderance in particular sex, or muscles affected.
Childhood-onset dystrophies are characterized by muscle weakening and wasting. Affected children may exhibit symptoms such as toe walking, difficulty climbing stairs or rising from a sitting position, and frequent falls when walking. As the disease progresses they may have difficulty in walking and become wheel-chair bound. Some children may have breathing as well as swallowing difficulties. The lung muscles, cardiac muscles and brain muscles may also be affected. Children may have enlarged calf muscles, develop scoliosis, vision & speech problems, foot disorders as well as impaired intellectual development.
The sub-types of childhood-onset muscular dystrophies differ in age of onset and preponderance in boys and girls.
Adolescent-Onset Muscular Dystrophies
The symptoms of the two forms of adolescent-onset muscular dystrophies, facioscalpohumeral MD and limb-girdle MD, become apparent during adolescence.
These sub-types affect muscles of the face, shoulder, upper arms and hips. These patients may have slanted shoulders, winged shoulder blades, and weakened upper arms and legs. Changes in facial appearance can also occur and they may experience difficulty while swallowing, chewing or speaking. Some patients may have lordosis, a condition of a curve in the lower back. As the disease advances the symptoms may become severe causing permanent disability and patients may become wheelchair-bound. Patients can have a normal life span but may have severe disability affecting their quality of life.
Adult-Onset Muscular Dystrophy
Adult-onset muscular dystrophies become apparent in adulthood and are of three forms: Distal MD, Myotonic MD, and Oculopharyngeal MD. All the sub-types occur between the ages of 40 and 60 years of age and commonly begin in the late 40’s..
The adult form of muscular dystrophies affects the muscles in the forearms, hands, lower legs, and feet. They may affect the muscles in the face, heart, lungs, central nervous system, adrenal and thyroid glands, eyes, and gastrointestinal tract. Individuals may have difficulty lifting their hands, stretching fingers, walking, climbing stairs, and standing on heels.
Patients with myotonic muscular dystrophy may have a characteristic hatched face and swan-like neck.
Patients with oculopharyngeal muscular dystrophy may have drooping eyelids, facial weakness, painful swallowing, voice changes, double vision, and cardiac irregularities.
Muscular dystrophy is usually diagnosed by collecting family history, medical history, and various diagnostic procedures.
- Family History
- Medical History
- Physical Examination
- Muscle biopsy to identify the type of muscular dystrophy
- DNA testing to identify the presence of mutated gene involved.
- Electromyography to assess the function and reflex of muscles and nerves.
- Blood test showing elevated levels of enzyme creatine kinase is a sign of muscular dystrophy.
- Ultrasonography scans helps in detecting muscle abnormalities in early stages.
Muscular dystrophies cannot be cured so the treatment goal is to prevent complications due to muscle weakness and wasting as well as to keep the patient as independent as possible.
Treatment options include the following:
Assisted ventilation can be used in patients with respiratory muscle weakness.
Drug therapy is provided to retard the muscle degeneration, regain strength, relieve muscle spasms, and to control seizures.
Physical therapy improves muscle flexibility, strengthens muscles, and improves movement. Physicians may also suggest the use of braces, splints and wheelchairs to help maintain mobility.
Other treatments such as electrical stimulation, occupational therapy and speech therapy may improve the quality of life of the patients.
In cases of contractures, scoliosis, and lordosis, corrective surgeries such as spine surgeries or tendon and muscle release surgeries may correct the deformities.
Muscular dystrophy if left untreated or not treated appropriately may lead to several complications such as
- Decreased ability of self-care
- Impaired mobility
- Lung failure
- Muscle contractures
- Mental impairment
Muscular dystrophy is a condition that cannot be cured and the available treatment options aim at providing symptomatic relief. Early medical intervention may have better outcomes and prevent the associated complications.