Fibromyalgia – physiological aspects Eva Kosek, MD., PhD., Assistant Professor Department of Clinical Neuroscience, Karolinska Institute and Stockholm Spine Center, Stockholm, Sweden. Lausanne 2008-05-22

Fibromyalgia - ACR 1990 criteria. History of widespread pain > 3 months Pain in at least 11 of 18 tender points on digital palpation. Wolfe et al., 1990

TP count - a crude screening tool for disturbed sensory processing? CWP (10-11%) Female/male ratio 1½:1 CWP + TP = FMS (0.5-4%) Female/male ratio 10:1 Clauw and Crofford 2003

Increased pain sensitivity to all tested modalities Pressure pain Heat pain Kosek et al 1995, 1996

Evidence of enhanced transmission/ processing of painful stimuli Subjectively similar pain intensity: Similar central nervous system activation in both groups. Same intensity of pressure stimulation: More pronounced and bilateral CNS activation in FM patients compared to healthy controls. Gracely et al., 2002

Lower my-opioidreceptor bindning capacity in patients Nucleus accumbens Lower my-opioidreceptor bindning capacity in patients with fibromyalgia Harris et al. 2007 Left amygdala Abnormal concentrations of pain related transmittor substances in the cerebrospinal fluid (i.e., serotonin, SP, glutamate) Right dorsal ACC Russell et al. 1992, 2002 Sarchielli et al. 2007

FMS patients have increased sensitivity to somatosensory stimuli independently of emotional factors – indicating augmentation of pain transmission and/or processing.

Future Challenges Develop clinically useful diagnostic tools to detect facilitation, central sensitisation/disinhibition in individual patients Further development of new treatments targeting these CNS-abnormalities Investigate the possibilities of secondary prevention