Fibromyalgia syndrome: definition and diagnostic aspects

Ever since it was first defined, fibromyalgia (FM) has been considered one of the most controversial diagnoses in the field of rheumatology, to the point that not everybody accepts its existence as an independent entity. The sensitivity and specificity of the proposed diagnostic criteria are still debated by various specialists (not only rheumatologists), whose main criticism of the 1990 American College of Rheumatology criteria is that they identify subsets of particular patients that do not reflect everyday clinical reality. Furthermore, the symptoms characterising FM overlap with those of many other conditions classified in a different manner. Over the last few years, this has led to FM being considered less as a clinical entity and more as a possible manifestation of alterations in the psychoneuroendocrine system (the spectrum of affective disorders) or the stress reaction system (dysfunctional symptoms). More recently, doubts have been raised about even these classifications; and it now seems more appropriate to include FM among the central sensitisation syndromes, which identify the main pathogenetic mechanism as the cause of skeletal and extra-skeletal symptoms of FM and other previously defined "dysfunctional" syndromes.