Chronic fatigue syndrome (CFS) is also known as postviral fatigue syndrome, neurasthenia, and myalgic encephalomyelitis. All describe an idiopathic syndrome characterized by disabling fatigue and other symptoms occurring chronically and exacerbated by minimal exertion.
Aetiology and pathogenesis—it is likely that multiple factors operate to predispose, precipitate, and perpetuate CFS: (1) predisposing factors—some individuals may be predisposed to develop CFS by virtue of genetics, personality, or other vulnerability; (2) precipitating factors—the condition may be precipitated by factors such as infection or psychological stresses; (3) perpetuating factors—for practical management the most important factors are those that perpetuate the illness and consequently act as barriers to recovery, including modifiable psychological, biological, behavioural, and social factors. Studies have reported a variety of biological abnormalities: few have been confirmed, but the most robust are (1) altered brain function, and (2) reduced hypothalamic-pituitary-adrenal axis responsiveness, although it is not clear if these are primary or secondary to inactivity....
