ABSTRACT
Fibromyalgia has been classified as primary and concomitatant. Primary fibromyalgia indicates that there is no underlying or concomitant medical condition that might have contributed to a patient’s pain. The tender point index is clinically simple to do. A possible problem is that it may incorporate some elements of a patient’s subjective complaints. Patients with fibromyalgia syndrome (FMS) have psychophysiological evidence of hyperalgesia to mechanical, thermal, and electrical stimulation. Central sensitization involves several neurophysiological aspects, including enhanced spinal cord dorsal horn neuronal excitability, which is associated with increased spontaneous neuronal activity, enlarged receptive fields, and an augmentation of stimuli transmitted by both large and small-diameter primary afferent fibers. Ketamine, an N-methyl-d-aspartate (NMDA) receptor antagonist, has been shown in placebo-controlled studies to reduce both temporal summation and muscle pain, indicating the importance of NMDA receptors in the pathophysiology of FMS. Nonrestorative sleep is one of the most common complaints in patients with FMS.
