Fibromyalgia is clinically defined as "a syndrome consisting of chronic symptoms of moderate to severe intensity including diffuse chronic pain without apparent cause and sensitivity to pressure, associated with fatigue, cognitive and sleep disorders and numerous complaints somatic”. It was recognized as a medical entity by the World Health Organization (WHO) in 1992 and classified as generalized chronic pain in the latest International Classification of Diseases (ICD).
Despite this institutional recognition, the disease is still the subject of controversy. The heterogeneity of its symptoms and the absence of identifiable organic lesion or dysfunction explains the doubts long expressed by part of the medical profession on the rational basis of this disease. It is possible that these anomalies exist but are not detectable by current exploration techniques. Also, fibromyalgia is no longer considered a psychosomatic illness, but a nociplastic pain caused by alterations in nociception, that is to say in the pain detection and control system.
A patient meets the diagnostic criteria for fibromyalgia when all three of the following criteria are met:
1. Generalized pain index (WPI) ≥ 7 and SS ≥ 5 or WPI 3-6 and SS ≥9 (Yes indication on Criterion 1).
2. Symptoms have been present at a similar level for at least 3 months.
3. The patient has no other problems that could explain the pain.