[Chronic fatigue syndrome--symptoms, signs, laboratory tests, and prognosis]

Chronic fatigue syndrome (CFS) is an undefined clinical problem and is perceived as a complex of multiple symptomatology with an unexplained persistent fatigue. Major symptoms include fatigue lasting for more than 6 months, low-grade fever, moderate lymphadenopathy, muscle and joint pain, and various psychological presentations. Since no specific laboratory tests are available, clinical diagnosis demands that known causes of chronic fatigue should be excluded. The pathogenesis is at present unknown, but it is suspected that CFS is a physical and psychological condition associated with some unrecognized infectious agent. Further study is needed to clarify the precise pathophysiology of this newly recognized entity.