ABSTRACT
Chronic fatigue syndrome (CFS) is a common, potentially disabling condition characterized by the symptoms of overwhelming, relapsing or persistent fatigue in the absence of any other concurrent medical and psychiatric illnesses. This is not a new disease. In the earlier part of the past century, similar illness was recognized in the epidemic forms that was preceded, or followed closely, by attacks of poliovirus infection in the community. It is the sporadic form of the disease that is now common. A significant proportion of current cases, but not all, show evidence of viral infection at the onset of their illness (post-viral fatigue syndrome).1 There is no real difference in the symptom complex and the natural history of illness between the post-viral and non-viral groups of patients with CFS. From the clinical perspective, the segregation of the post-viral group of CFS patients does not appear to serve any useful purpose. For both diagnosis and research purposes, current CFS case definitions must satisfy the modified CDC criteria (Table 15.1).2
