Pyke TL, et al. - This systematic review strived to examine the literature concerning proton magnetic resonance spectroscopy (H-MRS) measured glutamate levels in specific brain regions of fibromyalgia (FM) patients to ascertain if there is a relationship between raised glutamate levels and the presentation of FM. There was converging data in support of a dysregulation of pain processing in the central nervous system of FM patients, especially correlated with an increase in cerebral glutamate levels although the cause of FM remained inconclusive. Moreover, there was evidence to support an association between increased glutamate levels and an increase in FM symptoms.

• The clinicians searched the electronic databases to find original studies that used H-MRS to measure glutamate concentrations in the brains of FM patients.
• The search was conducted from MEDLINE, EMBASE Classic+Embase, PsychINFO, Cochrane Database of Systematic Reviews, Cochrane Database of Abstracts of Reviews of Effect, Cochrane Central Register of Controlled Trials.

• The clinicians selected 9 studies with a total of 482 participants for inclusion in the review.
• 7/8 studies that examined an association between cerebral glutamate levels and FM, demonstrated a positive association.
• They identified brain regions as having increased glutamate levels include the posterior cingulate gyrus, posterior insula, ventrolateral prefrontal cortex, and amygdala.
• Compared with healthy controls, 1 study reported a decrease in glutamate levels in the hippocampus of FM patients.
• 7/8 studies that examined the correlations between cerebral glutamate levels and FM symptoms, observed a significant positive correlation.