MUSCULAR DYSTROPHY (MD)
Muscular dystrophy is a group of inherited disorders that involve muscle weakness and loss of muscle tissue, which get worse over time.
Causes, incidence, and risk factors:
DMD is the most frequently occurring and one of the most rapidly progressive of the childhood neuromuscular disorders. It affects approximately (1 in 3000) live male births throughout the world. DMD type affects only boys (with extremely rare exceptions).
Muscular dystrophy (MD) refers to a group of genetic diseases characterized by progressive damage and weakness of facial, limb, breathing, and heart muscles. It is due to the lack of a key protein that is needed to maintain the integrity and proper function of the muscle. As the muscle tissue is damaged, the muscle bulk is reduced. Sometimes the muscle tissue can be replaced with fat and excessive scar tissue to make muscle appears larger than normal.
MD is categorized as listed below based on the clinical features, including inheritance pattern, muscles affected, and muscle biopsy features:
- Myotonic dystrophy
More than thirty genes have been identified to cause different types of muscular dystrophies. Many muscular dystrophies are now diagnosed through gene tests.
MD can affect people of all ages. Although some forms first become apparent in infancy or childhood, others may not appear until middle age or later. Duchenne muscular dystrophy is the most common form affecting children, while myotonic MD is the most common form affecting adults.
There are three primary types of inheritance in which the faulty gene that causes MD can be passed along to offspring:
- X-linked recessive: Genes that are X-linked recessive are carried by the female on one of the X chromosomes that determine the sex of the child. As such, only boys will inherit conditions determined by these genes. Their mothers, known as carriers, will usually not show signs of the disease. A son of a carrier of MD has about a fifty percent chance of developing the disease, while a daughter of a carrier has a fifty percent chance of being a carrier. If a boy is unaffected, he cannot pass on MD; however, daughters from a man with an X-linked dystrophy will all be carriers. Duchenne/Becker and Emery-Dreifuss are X-linked recessive.
- Autosomal recessive: For this type of inheritance, both parents must carry and pass on the faulty gene. Neither parent shows any symptoms, but each of their offspring, regardless of gender, will have a twenty five percent chance of developing the disease. Limb-girdle type 2 MD and distal myopathy are autosomal recessive.
- Autosomal dominant: In the case of autosomal dominant inheritance, an affected person will have MD even though only one faulty gene has been passed along. This faulty gene can come from either parent, and it can affect either sex. Each child of an affected parent will have a fifty percent chance of developing MD. For this type of inheritance, the severity of MD can vary greatly. It can be so mild that it is not recognized, but it can also be severe. Myotonic dystrophy, facioscapulohumeral dystrophy (FSHD), and oculopharyngeal muscular dystrophy (OPMD) are autosomal dominant.
Muscular dystrophies, or MD, are a group of inherited conditions, which means they are passed down through families. They may occur in childhood or adulthood. There are many different types of muscular dystrophy. They include:
- Becker muscular dystrophy
- Duchenne muscular dystrophy (DMD)
- Emery-Dreifuss muscular dystrophy
- Facioscapulohumeral muscular dystrophy
- Limb-girdle muscular dystrophy
- Myotonia congenita
- Myotonic dystrophy
- Symptoms vary with the different types of muscular dystrophy.
- All of the muscles may be affected. Or, only specific groups of muscles may be affected, such as those around the pelvis, shoulder, or face. Muscular dystrophy can affect adults, but the more severe forms tend to occur in early childhood.
- Mental retardation (only present in some types of the condition)
- Muscle weakness that slowly gets worse
- Delayed development of muscle motor skills
- Difficulty using one or more muscle groups
- Eyelid drooping (ptosis)
- Frequent falls
- Loss of strength in a muscle or group of muscles as an adult
- Loss in muscle size
- Problems walking (delayed walking)
Signs and tests:
A physical examination and your medical history will help the doctor determine the type of muscular dystrophy. Specific muscle groups are affected by different types of muscular dystrophy.
The doctor's exam may show:
Abnormally curved spine (scoliosis)
Joint contractures (clubfoot, clawhand, or others)
Low muscle tone (hypotonia)
Some types of muscular dystrophy involve the heart muscle, causing cardiomyopathy or disturbed heart rhythm (arrhythmias).
Often, there is a loss of muscle mass (wasting), which may be hard to see because some types of muscular dystrophy cause a build-up of fat and connective tissue that makes the muscle appear larger. This is called pseudohypertrophy.
A muscle biopsy may be used to confirm the diagnosis. In some cases, a DNA blood test may be all that is needed.
Other tests may include:
Heart testing - electrocardiography (ECG)
Nerve testing - electromyography (EMG)
Blood testing - including CPK level
Genetic testing for some forms of muscular dystrophy
This disease may also alter the results of the following tests:
Myoglobin - urine and blood
- Decreased ability to care for self
- Decreased mobility
- Lung failure
- Tightening of muscles around the joints (contractures)
- Mental impairment (varies)
There are no known cures for the various muscular dystrophies. The goal of treatment is to control symptoms. Physical therapy may help patients maintain muscle strength and function. Orthopedic appliances such as braces and wheelchairs can improve mobility and self-care abilities. In some cases, surgery on the spine or legs may help improve function. Corticosteroids taken by mouth are sometimes prescribed to children to keep them walking for as long as possible. The person should be as active as possible. Complete inactivity (such as bedrest) can make the disease worse.?
There is no cure for muscular dystrophy, although some drugs still in the trial stage have shown promise in slowing or delaying the progression of the disease. The only FDA-approved drug for Duchenne is a steroid, which may prolong ambulation by two years. For the time being, treatment is aimed at preventing complications due to the effects of weakness, decreased mobility, contractures, scoliosis, heart defects, and respiratory weakness.
Physical therapy: Physical therapy, especially regular stretching, is important in helping to maintain the range of motion for affected muscles and to prevent or delay contractures. Strengthening other muscles to compensate for weakness in affected muscles may be of benefit also, especially in earlier stages of milder MD. Regular exercise is important in maintaining good overall health, but strenuous exercise may damage muscles further. For patients whose leg muscles are affected, braces may help lengthen the period of time that they can walk independently.
Surgery: If a patient’s contractures have become more pronounced, surgery may be used to relieve the tension by cutting the tendon of the affected muscle, then bracing it in a normal resting position while it regrows.
Other surgeries are used to compensate for shoulder weakness in facioscapulohumeral MD, and to keep the breathing airway open for people with distal MD who sometimes experience sleep apnea. Surgery for scoliosis is often needed for patients with Duchenne MD.
Occupational therapy: Occupational therapy involves employing methods and tools to compensate for a patient’s loss of strength and mobility. This may include modifications at home, dressing aids, wheelchair accessories, and communication aids.
Nutrition: Nutrition has not been shown to treat any conditions of MD, but it is essential to maintaining good health.
Cardiac care: Arrhythmias are often a symptom with Emery-Dreifuss and Becker MD and may need to be treated with special drugs. Pacemakers may also be needed in some cases, and heart transplants are becoming more common for men with Becker MD.
Respiratory care: When the muscles of the diaphragm and other respiratory muscles become too weak to function on their own, a patient may require a ventilator to continue breathing deeply enough. Air may also be administered through a tube or mouthpiece. It is therefore very important to maintain healthy lungs to reduce the risk of respiratory complications.
The severity of disability depends on the type of muscular dystrophy. All types of muscular dystrophy slowly get worse, but how fast this happens varies widely. Some types of muscular dystrophy, such as Duchenne muscular dystrophy, are deadly. Other types cause little disability and people with them have a normal lifespan.
Genetic counseling is advised when there is a family history of muscular dystrophy. Women may have no symptoms but still carry the gene for the disorder. Duchenne muscular dystrophy can be detected with about 95% accuracy by genetic studies performed during pregnancy.
Why is genetic counselling important?
Each son of a female carrier has a 50% chance of inheriting DMD through his mother’s faulty X chromosome and each daughter has a 50% chance of being a carrier of the disorder in the same way. Soon after the diagnosis of DMD it is essential that genetic counselling is arranged, together with appropriate tests for those members of the family who are at risk of being carriers. Genetic counselling provides information on the inheritance pattern, risks to other family members, and the ‘prognosis’ (likely outcome of the disorder). This service also provides information about diagnostic testing, including prenatal testing, as well as carrier testing.
Cannabinoids Help Muscular Dystrophy Symptoms:
Cannabinoids are now known to have the capacity for neuromodulation, via direct, receptor-based mechanisms, at numerous levels within the nervous system. These provide therapeutic properties that may be applicable to the treatment of neurological disorders, including anti-oxidative, neuroprotective effects, analgesia, anti-inflammatory actions, immunomodulation, modulation of glial cells and tumor growth regulation. Beyond that, the cannabinoids have also been shown to be “remarkably safe with no potential for overdose."
“miraculously improved his quality of life so much so that he left his family and friends in New Jersey to live in California, where he can readily get his medication.”
Sublingual (under the tongue)-tincture (alcohol based) or infused oil (olive or food grade glycerin or coconut)
Topicals (salves, ointments, balms) for muscle pain and spasms.
Cannabinoids: increase appetite, analgesic (rid pain), muscle relaxant, saliva reduction, bronchodialation, and sleep induction.
CBD-rich strains are best choice. Sativa dominant x Indica.
Strains: Martian Mean Green, Mako Haze, Lethal Purple, Jamaican Pearl, Heavy Duty Fruity, G13 x NYC Diesel, F13, A-Train, Casey Jones, Aurora Borealis, Hash Heaven, Jack Flash #5, KC-45, Kushage, Lemon Skunk, Blue Dragon, Cinderella x Panama Red, Kerala Krush, Fruit of the Gods, Mandala #1.
1. Kliegman RM, Behrman RE, Jenson HB, Stanton BF. Muscular dystrophies. In: Kliegman RM, Behrman RE, Jenson HB, Stanton BF, eds. Nelson Textbook of Pediatrics. 18th ed. Philadelphia, Pa: Saunders Elsevier; 2007:chap 608.