Disorders with Somatic Presentation

Chronic fatigue syndrome (CFS) is characterized by disabling fatigue that significantly interferes with a person’s ability to carry out their normal daily activities. The core symptoms of CFS are: • physical and mental fatigue exacerbated by physical and mental exertion • cognitive impairment • disturbed sleep patterns • musculoskeletal pain • headaches. Levels of fatigue may fluctuate excessively from week to week or even day to day. Symptoms of CFS are also observed in a number of rare conditions (e.g. Lyme disease, multiple sclerosis, coeliac disease). Therefore, diagnosis is a matter of exclusion. A number of operational criteria to define CFS have been published. The US Center for Disease Control and Prevention (CDC) issued their current criteria in 1994, superseding the CDC criteria issued in 1988.1 UK case definitions have also been published.2 The principal distinction between the two is that the UK criteria insist that mental fatigue must be present, whereas the US criteria emphasize the importance of severe physical symptoms, reflecting the belief that CFS has a fundamental immunological pathology. The Fukuda et al. criteria, established by an international consensus, are the most recently published and widely implemented (Figure 1).