Muscular Dystrophy (APA style) Abstract Overview Muscular dystrophy, MD, is a group of inherited muscle diseases that weaken the muscles that help the body move (Clark, 1995). There are nine major forms of MD. These are Myotonic, Duchenne, Becker, Limb-girdle, Facioscapulohumeral, Congenital, Oculopharyngeal, Distal, and Emery-Dreifuss (Wikipedia contributors, 2009). The type of disease is based on a few factors which are as follows: when in a person’s life MD appears, the degree to which the muscle is affected, how the disease came about, and the rate at which the symptom progresses.
The cause of MD is linked to defects in certain genes and is determined by which gene is defective. This disease is inherited. In rare cases, muscular dystrophies aren’t inherited and occur because of a new gene abnormality or mutation (WebMD, 2005). The symptoms of the diseases vary depending on the type of MD. The main symptoms are progressive muscular wasting, poor balance, frequent falls, walking difficulty, waddling gait, calf pain, limited range of movement, respiratory difficulty, drooping eyelids (ptosis), gondal atrophy, scoliosis and finally the inability to walk (Wikipedia contributors, 2009).
Symptoms are not always present for diagnosis. Often the disease is diagnosed based on the results of a muscle biopsy. Sometimes all that is needed for diagnosis is a DNA blood test. There is no cure for any of the muscular dystrophies (WebMD, 2005). However, there are forms of therapy that reduce the muscle degeneration caused by MD. The therapies also vary depending on the type of MD. Some of the forms of helpful therapy include the following: Physical therapy, occupational therapy, orthotic intervention, speech therapy, and orthopedic instruments (Wikipedia contributors, 2009).
Causes According to Dowshen, Izenberg, and Bass (2002), all kinds of muscle dystrophy diseases are produced by the loss of muscle tissue caused by a genetic disorder. This loss of tissue is developed in the muscle cells, which become unable to perform their vital functions in the body. In the nucleus of cells, a single faulty gene in the DNA can cause diverse mutations, but muscular dystrophy, MD, results in the deficiency production of the dystrophin protein. Two most common forms of muscular dystrophy include the Duchene and Becker.
In Duchene muscular dystrophy (DMD), the lack of dystrophin contributes to the weakness of cell membranes until the muscle gets seriously damaged and lost, leading to death of children due to respiratory failure. DMD is the most common and severe type, affecting 1 in 3,600 boys. Since DMD is carried in the X-linked chromosome, mostly boys inherit the disease, while the presence of a normal gene prevents the development of this disease in girls. Becker muscular dystrophy (BMD) could be considered less serious than DMD, since it consists of the partial amounts of dystrophin produced.
At this time, the causes of this disease have been found only inherited in the genes of the affected person, or most common children (Dowshen et al, 2002). Symptoms Symptoms of Muscular Dystrophy, MD, vary from type to type. However, there are generalities that they all commonly share, such as: muscle weakness, lack of coordination, and gradually developed crippling, which results in loss of mobility, (Medical Encyclopedia, 2004). Becker’s MD, BMD, is considered to be a lesser case of Dystrophinopathy (a category of MD that branches off into different types and is a result of a genetic defect in the protein dystrophin. (Medical Encyclopedia, 2004). Usually affecting older boys to younger men, BMD starts at around the age of eleven to mid-twenties. Although Duchenne MD, DMD, is the most sever form of dystrophinopathy, the only difference between BMD and DMD is the age of onset, the level of intensity, and in DMD nearly the entire body is affected (MFMER, 1998). Usually most people affected by DMD die by their later teen years to early twenties, most commonly from muscle weakness in their respiratory and cardiac systems.
Congenital MD symptoms include joint deformities and muscle weakness (in general). Congenital MD is visible at child birth and tends to develop more slowly, however in more severe cases there have been signs of sever mental and speech complications, and seizures. Following the previous form of MD is Congenital Myotonic Dystrophy, CMD (MFMER, 1998). CMD affects infants and is found to be more severe. Symptoms range from severe muscle weakness, difficulty sucking and swallowing to cognitive impairment, and difficulty breathing.
Myotonic Muscular Dystrophy (also known as Steinert’s Disease), MMD, is more or less the adult version of CMD, except there are many more symptoms in the adult form, including: myotonia (the incapability to relax muscles at will), weakening of arm, leg, head, face, and neck muscles, weakening of muscles involved with breathing or swallowing, fainting or dizziness, weakening of hollowed internal organs (digestive tract and uterus), insomnia, frontal balding (in cases with men), cataracts, and mild forms of diabetes. Distal MD is another form of MD that affects the forearms, hands, lower legs, and feet.
It is slowly progressive and tends to show signs at around the ages of forty to sixty. Emery-Dreifuss MD is slowly progressive. This type of MD affects the shoulders, upper arms, shins, and results in irregular heartbeats and the stiffening and hardening of the spine and other muscles (MFMER, 1998). Facioscapulohumeral MD follows the trend in muscle weakness. This form focuses on the weakening of facial, shoulder, upper arm, abdomen, pelvic area, and the lower arm. Onset of this type of MD usually forms around teen to early adult years.
Limb-girdle MD affects the hips and shoulders, and slowly progresses to the arms and legs. Symptoms may begin in early childhood to early adulthood (MFMER, 1998). Oculophryngeal MD’s first signs include the drooping of the eyelids, then weakness of eye muscles, followed by the weakening of face, and throat muscles (results in difficulty swallowing). Signs and symptoms usually occur within persons of age forty to fifty (MFMER, 1998). Diagnosis Diagnosis of muscular dystrophy, MD, is initially determined by a thorough physical examination and your medical history from your physician.
To rule out other causes and to determine the distribution of symptoms is the reason the physical examination is performed. Family history may be very beneficial since MD is inherited and could show some clues. Unfortunately there could be new mutations which couldn’t be determined through family history. Electromyography, EMG, shocks muscles electrically and the reaction is abnormal in individuals with MD (Health-cares. net, 2005). Some types of MD cause cardiomyopathy or arrhythmias; this type involves the heart muscle. An electrocardiography (ECG) can be used to monitor changes in the heart.
Muscle biopsies are among the most reliable tests (Roye, 2003). According to health-cares. net (2005), they consist of taking a small piece of muscle and examining it under a microscope (fibers affected by MD are unusually large and interspersed with dead cells). Garcia (n. d. ) noted that “in the late stages of MD, fat and other tissues (like connective tissue) replace the dead muscle tissue”. Earlier diagnosis’s identified a specific mutation in the dystrophin gene using the DNA tests performed on blood samples (health-cares. net, 2005). From the blood, a DNA test may be sufficient in some cases (Roye, 2003).
Garcia (n. d. ) noted that “CPK Assay measures the enzyme creatine phosphokinase which has leaked from a damaged muscle cell into the blood stream”. DMD is not commonly screened prenatally. Amniocentesis or CVS screening can be used to diagnosis DMD if there is a family history of the disease and the DMD mutation is known (Garcia, n. d. ). Single condition amplification/internal primer (SCAIP) sequencing, a new DNA test, allows doctors to have a much more accurate picture of the entire dystrophin gene so they can find multiple variations, providing more than just one type of diagnosis.
In the next few years this test should become more widely available to the general public (health-cares. net, 2005). Treatment Unfortunately there are no known cures for MD and limited medications that can be used towards the symptoms. Treatment is centered on physical therapy and occupational therapy; it is directed at preventing the complications of weakness, including decreased mobility and dexterity, contractures, scoliosis, heart defects, and respiratory weaknesses to maximize the quality of life. Bedrest can worsen the disease so activity, to the degree tolerated, is encouraged.
To maintain function and muscle strength, physical therapy may help some individuals. In order to improve mobility and self-care abilities, orthopedic appliances like braces and wheelchairs may be used. Pacemakers may be required for individuals containing Emery-Dreifuss MD and or Myotonic MD (Health-cares. net, 2005). Improving function and slowing deterioration may be done by surgery on the spine or lower extremities. However, in certain circumstances surgery may be a necessity. In this case the surgery would be to correct severe contractures, compensate for shoulder weakness, lift eyelids that are affected by
Oculopharyngeal MD, correct scoliosis, and to keep the airways open in cases of sleep apnea (Wikipedia contributors, 2009). Ventilators are also used for OPMD (Clark, 1995). DMD is treated with prednisone and MMD is treated with either phenytoin or quinine to relax the muscles (Wikipedia contributors, 2009). References Clark, A. (1995). Muscular dystrophy. The Nemours Foundation. Retrieved November 05, 2009from http://kidshealth. org/teen/diseases_conditions/bones/muscular_dystrophy. html Dowshen, S. A. , Izenberg, N. , & Bass, E. R. (2002). The kids health guide for parents: Pregnancyto age 5. Chicago: McGraw-Hill Professional.
Garcia, S. (n. d. ). Muscular dystrophy: A walk in their shoes. Retrieved November 20, 2009 fromhttp://www. cdc. gov/excite/ScienceAmbassador/ambassador_pgm/lessonplans/Garcia%20 MD%20Lesson%20Plan. pdf Health-cares. net. (2005). How is muscular dystrophy diagnosed? Retrieved November 20, 2009from http://bone-muscle. health-cares. net/muscular-dystrophy-diagnosis. php and http://bone-muscle. health-cares. net/muscular-dystrophy-treatment. php MayoClinic. com. (1998). Muscular Dystrophy. Mayo Foundation for Medical Education and Research (MFMER): Author. Retrieved November 24, 2009 from http://www. ayoclinic. com/health/muscular-dystrophy/DS00200/DSECTION=symptoms Medical Encyclopedia (2004, October). Muscular Dystrophy. Retrieved November 14, 2009 from http://www. nlm. nih. gov/medlineplus/ency/article/001190. htm Muscular Dystrophy. (2009, November 22). In Wikipedia, The Free Encyclopedia. Retrieved 16:16, November 24, 2009, from http://en. wikipedia. org/w/index. php? title=Muscular_dystrophy&oldid=327342753 Roye, B. D. (2003). Muscular Dystrophy. A. D. A. M. , Inc. Retrieved November 20, 2009 from http://health. allrefer. com/health/muscular-dystrophy-diagnosis-tests. html
