Chronic fatigue syndrome/myalgic encephalo-myelitis--pathophysiology, diagnosis and treatment.

Abstract

Pathophysiology Heredity can predispose to chronic fatigue syndrome/myalgic encephalomyelitis (2), as can certain personality traits such as high levels of perfectionism (3). Long-lasting infections, such as mononucleosis, are established triggers (4), but critical life events can also play a part (5). Maintaining factors include altered cognitive function, especially executive dysfunction (6), increased sympathetic and decreased parasympathetic nerve activity, which affects cardiovascular regulation (7, 8), and reduced responsivity of the hypothalamic-pituitary-adrenal axis (HPA axis) (9). A number of studies have also reported immunological changes characterised by mild systemic inflammation (increase in proinflammatory cytokines) and impaired NK cell function (10), but here there are contradictory findings. One problem is publication bias, whereby sporadic positive findings are reported because they are original and exciting, but in time turn out to be false positives. This problem was illustrated in a recently published review article (11). The authors examined 38 articles featuring a total of 77 immunological markers, many of which were reported as positive in single studies. The only replicated positive marker was TGF-, the others were negative in the vast majority of studies. Whether TGF- is a