The diagnostic history of Fibromyalgia as an actual clinical diagnosis has followed a long and winding road. First observed in the nineteenth century (though evidence throughout history supports the hypothesis that Fibromyalgia has been around for much longer under different names), ‘fibrositis syndrome’ began to appear in the medical literature in the 1960s. However, it was not until the 1970s that the modern understanding of Fibromyalgia was first addressed from a true research standpoint in an effort to discern its clinical identity. The first researchers to address fibrositis (as it was still called at the time) were Moldofsky and Smythe. They characterized the disease based on two key criteria: the existence of numerous tender points and non-refreshing sleep. The tender points identified by Moldofsky and Smythe were described as being sensitive to pressure, and patients had to have widespread aching for longer than three months, as well as disturbed sleep with concurrent morning fatigue and stiffness. Moldofsky and Smythe published their proposed criteria for characterizing fibrositis in a 1977 issue of the Bulletin of the Rheumatic Diseases, which was subsequently mailed to general practitioners and rheumatologists courtesy of the United States Arthritis Foundation. Unfortunately, Moldofsky and Smythe’s criteria for diagnosis were limited in that they did not provide a definitive method for determining sleep disturbance, fatigue and widespread aching, whereas the tender point counts were clearly defined. Despite their shortcomings, the criteria put forth by Moldofsky and Smythe offered the first concrete description and set of criteria for diagnosing what we now know as Fibromyalgia.
Throughout the 1980s, tender points quickly became the focal point for diagnosing Fibromyalgia. Moldofsky and Smythe’s criteria required tenderness at 12 of 14 points, however since this degree of tenderness was quite rare among most suffers, other research teams began to suggest modified versions of the tender point criteria throughout the 1980s. In addition, most of the published reports revealed that clinicians were using not only different numbers of tender points, but also different methods of examinations to establish a diagnosis. Finally, in 1981, Yunus et al. proposed a formal set of criteria to aid in the diagnosis of Fibromyalgia. These criteria required aching, pain, and stiffness for a minimum of three months as well as the presence of at least five tender points. Furthermore, Yunus et al. required patients to have three of the following ten symptoms: decreased physical activity in response to symptoms, weather-related symptom aggravation, stress/anxiety-related symptom aggravation, sleep disturbances, fatigue/tiredness, anxiety, headaches, irritable bowel syndrome, swelling, and/or numbness. The Yunus et al. criteria de-emphasized the reduced pain threshold that the Moldofsky and Smythe criteria had emphasized, and instead placed a greater focus on symptoms.
The variations in diagnostic criteria and methods ultimately culminated in the American College of Rheumatology (ACR) establishing official classification criteria for Fibromyalgia in 1990. They achieved this by conducting a study in which 22 Rheumatologist each evaluated 40 patients from their own practices: 10 with Fibromyalgia, 10 with both Fibromyalgia and rheumatoid arthritis, 10 without Fibromyalgia but with other rheumatic pain disorders (such as osteoarthritis), and 10 rheumatoid arthritis patients who did not have Fibromyalgia. Each patient received a tender point examination at a number of points (including some not previously established as being sensitive to pressure in Fibromyalgia patients), as well as a symptomatic evaluation that assessed the symptoms described by Yunus et al. Each Rheumatologist was trained to administer the tender point examination in the same fashion. The overall goals of the 1990 ACR study were to establish an official number of tender points for both examining patients and determining a diagnosis of Fibromyalgia, as well as to determine factors (symptoms, etc.) that would help clinicians differentiate between Fibromyalgia and other rheumatic diseases. Based on their findings, the researchers concluded that the classification criteria for Fibromyalgia should consist of the presence of widespread pain and a minimum of 11 out of 18 tender points. These criteria placed a decreased pain threshold as the hallmark identifier of Fibromyalgia, and also created the concept of “chronic widespread pain.” Furthermore, the endorsement by the ACR helped to finally establish Fibromyalgia as a true clinical diagnosis.
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2. Yunus M, Masi AT, Calabro JJ, Miller KA, Feigenbaum SL. Primary Fibromyalgia (fibrositis): clinical study of 50 patients with matched normal controls. Semin Arthritis Rheum. 1981;11:151-171.
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