Are peripheral pain generators important in fibromyalgia and chronic widespread pain?

Fibromyalgia (FM) is a chronic widespread pain syndrome (CWPS) that is generally considered to be the result of a dysfunctional central pain modulating system. It is thought to importantly involve the descending pain inhibitory system. FM is known to be associated with multimodal hypersensitivity: mechanical, thermal, visual, and auditory. It is associated with a variety of comorbid conditions including irritable bowel syndrome, painful bladder, migraine headache, and temporo-mandibular joint syndrome. The relationship of the comorbid conditions to FM has not been clear. They can be considered to be the result of hyper-effective ascending central pain transmission resulting from deficient descending pain inhibition, or they can be considered as clinical entities in themselves, whose importance in FM lies in their acting as peripheral pain generators that enhance or initiate central sensitization, thereby contributing to chronic widespread pain. There may, of course, be some truth in both of these concepts. The presence of peripheral pain generators that lead to central sensitization initiating or maintaining CWPS or FM remains controversial, however. This question is addressed in a masterful study by Albrecht et al. [1], published in this issue.