Fibromyalgia; Overview

NWHRC Health Center - Fibromyalgia, June 15, 2005

Fibromyalgia syndrome (FS) is a chronic disorder characterized by widespread musculoskeletal pain, fatigue, multiple tender points and poor sleep. "Tender points" refers to tenderness that occurs in precise, localized areas, particularly in the neck, spine, shoulders and hips. People with FS may also experience morning stiffness, fatigue, increased headaches or facial pain, irritable bowel syndrome, depression, anxiety and cognitive symptoms (troubles with concentration, short-term memory and handling multiple tasks).

Diagnosis of FS has been controversial because there are no specific laboratory tests to identify the disorder. Until the 1990s (and even during much of that decade), many health care professionals thought FS was largely psychosomatic (in a patient's mind), in part because the disease is often associated with depression. In recent years, however, health care professionals have come to understand that psychological factors contribute to an increased risk for disability, and may actually stimulate the central nervous system mechanisms that may lead to fibromyalgia. More important, people with fibromyalgia have been found to have different pain perception thresholds than healthy people or patients with depression only. It has also been found to be different from those with chronic fatigue, who do not have abnormal pain perception.

According to the American College of Rheumatology (ACR), FS affects three million to six million Americans and is the second most common rheumatic ailment after osteoarthritis. As many as 80 percent of individuals diagnosed with FS are women. The syndrome primarily occurs in women of childbearing age, but children, post-menopausal women, the elderly, and men also can be affected. FS can be disabling: A survey of fibromyalgia patients found that 15 percent to 25 percent considered themselves disabled and 26 percent were receiving at least one form of disability payment.

Fibromyalgia is an abnormal processing of sensory information in which non-painful stimuli are perceived as painful, and the pain of painful stimuli is increased. The severity of fibromyalgia symptoms varies from person to person. For some women, pain or other symptoms can be so intense that they interfere with daily activities. For others, symptoms may cause discomfort, but are not incapacitating.

Light, unrefreshing sleep is one of the hallmarks of FS. Women with FS often have restless sleep, and may suffer restless-legs syndrome during the day. The problem isn't with quantity--a woman with fibromyalgia may get eight to 10 hours of sleep but not enough of a form of deep sleep called "delta sleep." The name stems from the brain wave pattern produced in an electroencephalogram). Lack of deep sleep makes people with or without FS feel achy, tired and less able to concentrate. Sleep problems could thus be not only a symptom of FS, but also an underlying cause of many of the symptoms.

In addition to sleep problems, researchers have found many other links between various health problems and FS:

FS may arise following an injury or trauma. For instance, a percentage of whiplash victims develop FS. Similarly, in an injury such as carpal tunnel syndrome, which may result in a chronic persistent regional pain, the pain may spread to adjacent areas in the upper extremities and neck, becoming a widespread pain. Sometimes the widespread pain may go on to become fibromyalgia, possibly because chronic, persistent pain can result in a widening of the pain-receptor field within the central nervous system.

An infectious agent may trigger FS in susceptible people. Lyme disease is under study as one such trigger-one study found 10 percent to 25 percent of patients with Lyme disease develop fibromyalgia.

FS is also associated with autoimmune disorders such as systemic lupus erythematosus and rheumatoid arthritis. People with these disorders are at higher risk of developing FS, however the reverse is not true. Women with fibromyalgia who develop Raynaud's phenomenon, characterized by extreme sensitivity to cold in the extremities, may be misdiagnosed as having lupus or scleroderma.

Recent studies show that some women with fibromyalgia may have abnormally low levels of growth hormone. People whose bodies make inadequate amounts of growth hormone experience many of the same symptoms as people with fibromyalgia. These low levels of growth hormone may be related to disturbed sleep or abnormal circadian rhythms.

Central sensitization has been proposed as the unifying concept for FS and related conditions such as chronic fatigue syndrome, irritable bowel syndrome, Gulf War syndrome, and temporomandibular joint pain and dysfunction syndrome. There are especially strong links between irritable bowel syndrome and fibromyalgia and between chronic fatigue syndrome and fibromyalgia. More than half of women with IBS or CFS also have fibromyalgia symptoms.

Most researchers agree that fibromyalgia is a disorder of central processing with neuroendocrine/neurotransmitter dysregulation. An increasing number of studies show multiple physiological abnormalities in the fibromyalgia patient, including increased levels of substance P in the spinal cord, low levels of blood flow to the thalamus region of the brain, HPA Axis hypofunction, low levels of serotonin and tryptophan and abnormalities in cytokine function.