Fibromyalgia, sleep disorder and chronic fatigue syndrome.

Various research studies show that the amalgam of disordered sleep physiology, chronic fatigue, diffuse myalgia, and cognitive and behavioural symptoms constitutes a non-restorative sleep syndrome that may follow a febrile illness, as in the chronic fatigue syndrome. Where rheumatic complaints are prominent such a constellation of disturbed sleep physiology and symptoms also characterizes the fibromyalgia disorder. In contrast to the chronic fatigue syndrome, fibromyalgia is associated with a variety of initiating or perpetuating factors such as psychologically distressing events, primary sleep disorders (e.g. sleep apnoea, periodic limb movement disorder) and inflammatory rheumatic disease, as well as an acute febrile illness. The chronic fatigue syndrome and fibromyalgia have similar disordered sleep physiology, namely an alpha rhythm disturbance (7.5-11 Hz) in the electroencephalogram (EEG) within non-rapid eye movement (NREM) sleep that accompanies increased nocturnal vigilance and light, unrefreshing sleep. Aspects of cytokine and cellular immune functions are shown to be related to the sleep-wake system. The evidence suggests a reciprocal relationship of the immune and sleep-wake systems. Interference either with the immune system (e.g. by a viral agent or by cytokines such as alpha-interferon or interleukin 2) or with the sleeping-waking brain system (e.g. by sleep deprivation) has effects on the other system and will be accompanied by the symptoms of the chronic fatigue syndrome.