The significance of the sleeping-waking brain for the understanding of widespread musculoskeletal pain and fatigue in fibromyalgia syndrome and allied syndromes.

The clinical focus of rheumatologists on the widespread pain and numerous tender points in specific anatomic regions in their patients who show no evidence for disease pathology has lead to the characterization of such peripheral symptoms as a specific disorder of the musculoskeletal system, now commonly known as fibromyalgia. This rheumatologic diagnostic entity has resulted in relative inattention to an understanding of their patients' common complaints of unrefreshing sleep, chronic fatigue and psychological distress. Experimental evidence from humans and animal studies indicate that there is an inter-relationship of disturbances in the physiology of the sleeping-waking brain with the widespread musculoskeletal pain, chronic fatigue, and psychological distress in patients with hitherto unexplained pain/fatigue illnesses, e.g., fibromyalgia and chronic fatigue syndromes. The emerging knowledge of the dysfunction of the nervous system in such patients has lead to the study of novel medications that affect neurotransmitter functions, e.g., pregabalin, serotonin/noradrenaline compounds and sodium oxybate that are shown to improve many of the symptoms of such patients.