Fibromyalgia - What Causes Fatigue: Chronic Fatigue

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Fibromyalgia

Fibromyalgia is similar to CFS, so similar that many experts view them as variants of the same condition. Both disorders are more common among women; both produce symptoms of unremitting fatigue and muscle pain; and both can begin following an infection. But in fibromyalgia, pain, not fatigue, is the predominant symptom.

People with fibromyalgia have many of the same abnormalities of the immune system, endocrine system, and nervous system found in those with CFS. However, some studies have found that, in some tests, the abnormalities of fibromyalgia differ from those of CFS. Psychiatric problems, such as depression and anxiety, are also more common in people with fibromyalgia than in the general population.

Fibromyalgia causes pain and stiffness in characteristic spots called "tender points" (see Figure 7). The area between the shoulder blades and the bottom of the neck tends to be the most painful. Apparently, the musculoskeletal pain of fibromyalgia reflects a heightened sensitivity to pain rather than muscular abnormalities. People with fibromyalgia have higher than normal levels of substance P, a neurotransmitter involved in pain sensation, in their cerebrospinal fluid. Some research has found that they also have low levels of insulin-like growth factor (IGF), also called somatomedin-C, a chemical that helps keep muscles strong and in good repair; other studies find no differences in IGF levels.

Figure 7: Tender points in fibromyalgia Areas of tissue that become painful when pressed, particularly in the locations shown, are called "tender points." They often develop in people with fibro­myalgia, occur less frequently in people with other conditions (such as chronic fatigue syndrome), and occur rarely in healthy individuals.

Treating fibromyalgia

Given the similarity between fibromyalgia and CFS, it's not surprising that, in many cases, the same treatments are helpful for both. Aerobic exercise — such as swimming, walking, biking, or low-impact stepping classes — has been shown to reduce muscle pain and tenderness. Heat and massage may also give short-term relief from musculoskeletal pain. Several randomized clinical trials have found that low-dose tricyclic antidepressants improve sleep, elevate mood, and relieve muscle pain.

Last updated:	January 23, 2007