According to MedlinePlus, a service of the U.S. National Library of Medicine and the U.S. National Institutes of Health, there are numerous problems that can affect the body's muscles, and muscle disorders can cause pain, weakness or paralysis. Muscle disorders may be caused by genetics, injury or overuse, inflammation, infections, and certain medicines. The severity of muscular diseases ranges from mild to severe. Relatively common types of muscular disorders include muscular dystrophy, myasthenia gravis and fibromyalgia.
Duchenne Muscular Dystrophy
Duchenne muscular dystrophy, or DMD, is one of a group of nine hereditary muscle diseases collectively known as muscular dystrophy. According to the Muscular Dystrophy Association, or MDA, DMD is a genetic, degenerative disease that primarily affects the voluntary muscles. DMD is caused by the absence of dystrophin, a protein that links a muscle fiber's cytoskeleton to the extracellular matrix through the cell membrane. DMD manifests during early childhood, typically between the ages of 2 and 6. The most common symptoms associated with DMD include generalized muscle weakness and wasting, especially in the muscles of the hips, pelvis, thighs and shoulders. The MDA notes that people with DMD often have enlarged calf muscles. Over time, DMD affects all the body's voluntary muscles, including the heart and the muscles of respiration.
Myasthenia Gravis
According to the National Institute of Neurological Disorders and Stroke, or NINDS—a division of the National Institutes of Health—myasthenia gravis is characterized by varying degrees of weakness of the body's skeletal muscles. NINDS states that myasthenia gravis is a chronic autoimmune neuromuscular disease whose name means "grave muscle weakness." The most common symptom associated with myasthenia gravis is muscle weakness during bouts of activity that resolve following periods of rest, and the most common muscles affected by the condition include the following: the ocular muscles and the muscles that control eyelid movement; the muscles of facial expression; and the chewing, talking and swallowing muscles. Other muscles that may be affected include the breathing muscles and the muscles that control neck and limb movements. Despite the seriousness of the condition, with contemporary treatment methods, life expectancy is not decreased for most people with this condition.
Fibromyalgia
The Mayo Clinic states that fibromyalgia is a chronic condition involving diffuse pain in a person's muscles, tendons and ligaments, along with fatigue, sleep disturbances and the presence of numerous tender points throughout the body. According to the Mayo Clinic, fibromyalgia occurs in approximately 2 percent of the American population, and women have a significantly greater likelihood of developing the disorder than do men. Also, the risk of fibromyalgia increases with age. Although fibromyalgia symptoms may manifest after physical or emotional trauma, in most cases there does not appear to be a single precipitating event. Common locations for fibromyalgia-related tender points include the following: the back of the head, between the shoulder blades, the top of the shoulders, the front sides of the neck, the upper chest, the outer elbows, the upper hips, the sides of the hips and the inner knees. People with fibromyalgia are likely to have other conditions too, such as chronic fatigue syndrome, headaches, osteoarthritis and rheumatoid arthritis, among many others.
