Fibromyalgia is a chronic condition that causes pain, stiffness, and tenderness of the muscles, tendons, and joints. Fibromyalgia is also characterized by restless sleep, awakening feeling tired, chronic fatigue, anxiety, depression, and disturbances in bowel function. Fibromyalgia is sometimes referred to as fibromyalgia syndrome and abbreviated FMS. Fibromyalgia was formerly known as fibrositis.
While fibromyalgia is one of the most common diseases affecting the muscles, its cause is currently unknown. The painful tissues involved are not accompanied by tissue inflammation. Therefore, despite potentially disabling body pain, patients with fibromyalgia do not develop body damage or deformity. Fibromyalgia also does not cause damage to internal body organs. In this sense, fibromyalgia is different from many other rheumatic conditions (such as rheumatoid arthritis, systemic lupus, and polymyositis). In those diseases, tissue inflammation is the major cause of pain, stiffness, and tenderness of the joints, tendons and muscles, and it can lead to joint deformity and damage to the internal organs or muscles.
What causes fibromyalgia?
The cause of fibromyalgia is not known. Those affected experience pain in response to stimuli that are normally not perceived as painful. Researchers have found elevated levels of a nerve chemical signal, called substance P, and nerve growth factor in the spinal fluid of fibromyalgia patients. Levels of the brain chemical serotonin are also relatively low in patients with fibromyalgia. Studies of pain in fibromyalgia have suggested that the central nervous system (brain) may be somehow supersensitive. Scientists note that there seems to be a diffuse disturbance of pain perception in patients with fibromyalgia.
Also, patients with fibromyalgia have an impaired non-rapid eye movement, or non-REM, sleep phase (which likely, at least in part, explains the common feature of waking up fatigued and unrefreshed in these patients). The onset of fibromyalgia has been associated with psychological distress, trauma, and infection.
Who does fibromyalgia affect?
Fibromyalgia affects predominantly women (over 80% of those affected are women) between the ages of 35 and 55. Less commonly, fibromyalgia can also affect men, children, and the elderly. It can occur independently or can be associated with another disease, such as systemic lupus or rheumatoid arthritis. The prevalence of fibromyalgia varies in different countries. In Sweden and Britain, 1% of the population is affected by fibromyalgia. In the United States, approximately 4% of the population has fibromyalgia.