Diagnostic criteria and differential diagnosis of the fibromyalgia syndrome

Objectives: The goals of this presentation are to review the American College of Rheumatology [ACR] research classification criteria for the fibromyalgia syndrome [FMS] and to show how they facilitate the differential diagnosis of pain in a variety of clinical presentations. Findings: The ACR criteria were developed directly from a research validation study and apply best to that setting. In lieu of a better resource, these criteria have been applied to community clinical practice as well. The design of the ACR Criteria study is outlined. The results show how the ACR Criteria directly follow the study findings. In patients with chronic widespread pain, the presence of 11 of 18 anatomically defined tender points [TePs] sufficiently sensitized to be painful when stimulated by four kilograms of digital pressure identified FMS irrespective of concomitant conditions, including conditions with the potential to cause pain. The ACR criteria depend only on pain, so they do not take into consideration other common features of FMS, such as insomnia, visceral syndromes, headache, or affective symptoms. The ACR Criteria definition allows the concomitant diagnosis of FMS in patients known to have painful rheumatic, neurological, infectious, neoplastic, inherited, and acquired disorders. Conclusions: The ACR criteria for FMS were developed to facilitate research regarding this common painful condition, but have been applied to community clinical care as well. These criteria distinguish FMS from other painful disorders and disclose overlapping diagnoses.