Prevalence of myofascial trigger points in fibromyalgia: the overlap of two common problems.

With the objective evidence of their existence, myofascial trigger points (MTrPs) contribute to an increasing number of chronic regional and widespread pain conditions. The widespread spontaneous pain pattern in fibromyalgia (FM) is a summation of multiple regional pains due to active MTrPs. A regional pain in FM is from local active MTrPs and/or referred from remote active MTrPs. Positive tender points specified in FM are MTrPs, either active or latent. Manual stimulation of active MTrPs located in the muscles in different body regions completely reproduced overall spontaneous FM pain pattern. Active MTrPs as tonic peripheral nociceptive input contribute tremendously to the initiation and maintenance of central sensitization, to the impairment of descending inhibition, to the increased excitability of motor units, and to the induction of sympathetic hyperactivity observed in FM. The considerable overlap of MTrPs and FM in pain characteristics and pathophysiology suggests that FM pain is largely due to MTrPs.