Fibromyalgia patients show brain abnormalities

NEW YORK (Reuters Health) - French researchers have shown that patients with fibromyalgia have abnormal blood flow in the brain, which may be related to the underlying cause of the condition.

"We found brain functional differences between patients with fibromyalgia and those who do not have the disorder," lead investigator Dr. Eric Guedj told Reuters Health. "These brain functional abnormalities were correlated with the severity of the disease, but not with anxiety or depression, in regions of the brain known to be involved in pain processing."

To visualize these abnormalities, the researchers used single photon emission computed tomography (SPECT), a special type of CT scanning test in which a small amount of a radioactive compound is injected into a vein. This allows SPECT to make a detailed image of areas in which the radioactive material is taken up by the cells, providing information about blood flow to tissues and metabolism in the body.

Guedj of Center Hospitalo-Universitaire de la Timone, Marseilles, and colleagues studied 20 patients with fibromyalgia and 10 healthy individuals. The findings are reported in the Journal of Nuclear Medicine.

Overall, the findings "suggest that fibromyalgia may be defined as a brain functional disorder involving these regions," Guedj concluded.

The underlying cause of fibromyalgia is not known. Previously the classification of fibromyalgia has been questioned by some and thought by others to be associated with depression. Other possible causes are sleep disorders, infection, abnormalities of the nervous system and changes in muscle metabolism.

SOURCE: Journal of Nuclear Medicine, November 2008.