Monday, February, 13, 2012

Fibromyalgia - Causes

Table of Contents

Brain Chemicals and Hormonal Abnormalities

Many abnormalities of hormonal, metabolic, and brain chemical activity have been described in studies of fibromyalgia patients. Changes appear to occur in several brain chemicals, although no regular pattern has emerged that fits most patients. Because there has been no clear cause-and-effect relationship established, it may be that fibromyalgia is a result of the effects of pain and stress on the central nervous system, which lead to changes in brain circuitry, rather than a brain disorder itself.

Serotonin. Of particular interest to researchers is serotonin, an important nervous system chemical messenger found in the brain, gut, and other areas of the body. Serotonin plays important roles in creating feelings of well-being, adjusting pain levels, and promoting deep sleep. Serotonin abnormalities have been linked to many disorders, including depression, migraines, and irritable bowel syndrome. Lower serotonin levels have also been noted in some patients with fibromyalgia.

Stress Hormones. Researchers have also found abnormalities in the hormone system known as the hypothalamus-pituitary-adrenal gland (HPA) axis. The HPA axis controls important functions, including sleep, the stress response, and depression. Changes in the HPA axis appear to produce lower levels of the stress hormones norepinephrine and cortisol. (By contrast, levels of stress hormones in depression are higher than normal.) Lower levels of stress hormones lead to impaired responses to psychological or physical stresses. (Examples of physical stress include infection or exercise.)

Certain factors may inappropriately trigger a person's stress response and contribute to the development of fibromyalgia, including:

  • Infections (Epstein-Barr virus, Lyme disease)
  • Physical trauma (such as a car accident)
  • Emotional stress
  • Hormonal changes (such as an underactive thyroid gland)
  • Medications
Hypothalamus
The hypothalamus is a highly complex structure in the brain that regulates many important brain chemicals.
Adrenal glands Click the icon to see an image of the adrenal glands.

Review Date: 12/27/2010
Reviewed By: Harvey Simon, MD, Editor-in-Chief, Associate Professor of Medicine, Harvard Medical School; Physician, Massachusetts General Hospital. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.

A.D.A.M., Inc. is accredited by URAC, also known as the American Accreditation HealthCare Commission (www.urac.org)