A relatively new diagnostic tool, the Symptom Intensity Scale, is an easy, quick way to assess both regional pain and fatigue in a patient. It can be used to establish the diagnosis of fibromyalgia syndrome and measure its severity in daily clinical practice without the need to count tender points. It can also be used to detect fibromyalgia as a comorbidity in other clinical illnesses; by uncovering fibromyalgia, the questionnaire serves as a surrogate measure of depression, anxiety, other serious personality disorders, previous or ongoing abuse, and, when fatigue is the dominant symptom, a consideration of obstructive sleep apnea—all part of the pathoetiology of fibromyalgia in that individual.
This manuscript reviews previous criteria and definitions by which fibromyalgia syndrome was recognized, describes how the new questionnaire was developed, and discusses its implications. It is not meant as a review of the pathogenesis or treatment of fibromyalgia or when to send the patient to the rheumatologist. Each of those topics requires lengthy and complex discussions, which are beyond the scope of this paper.
A COMMON, MULTIFACTORIAL DISEASE
The pathoetiology of fibromyalgia syndrome is rooted in disordered sleep, increased stress, and abnormal neurosensory processing, with secondary endocrine and autonomic dysfunction in those who are genetically predisposed.1–4 Because fibromyalgia is multifactorial, it is best understood from the perspective of an inclusive biopsychosocial model rather than a limited biomedical model.5 Its characteristic signs and symptoms are best understood as emanating from a physiologic state, called central sensitization syndrome, in which the nervous system overresponds to stimuli.1,3 This anomalous state of heightened nervous system response is not confined to the peripheral nervous system, but is also present in the autonomic and central nervous systems.3,4
Fibromyalgia syndrome is common, affecting 0.5% to 5% of the general population,6 and is either the second or third most common diagnosis in a rheumatology practice. Importantly for internists, a diagnosis of fibromyalgia syndrome should be made in 10% to 15% of primary care patients.7 The high prevalence alone demands diagnostic recognition.
KNOWN IN HISTORY AND LITERATURE
Although the designation fibromyalgia syndrome is new, the illness has been with us for as long as we’ve been us. In fact, the word rheumatology may have its origin in fibromyalgia syndrome. Galen (about 180 ad) blamed the symptoms of diffuse pain on the “rheuma,” which has been interpreted as “a great fluxion which races [from the center?] to various parts of the body, and goes from one to another.”8 (Is this the origin of blood-letting as a treatment for diseases?) In 1592, the French physician Guillaume de Baillou introduced the term rheumatism to describe both muscle and joint pain.9
Literature also knows fibromyalgia syndrome. Hans Christian Andersen described a supersensitive princess for whom a pea beneath many mattresses was sufficient to ruin her sleep. In The Fall of the House of Usher, Edgar Allan Poe described Roderick Usher as having an “acute bodily illness and mental disorder that oppressed him.” Usher would wear garments of only soft texture because rough cloth was painful. Light hurt his eyes, forcing him to keep the curtains drawn. Although he had previously played and enjoyed violin music, he could no longer tolerate the sound of the violin. In fact, he suffered such hyperacusis that he could hear his sister moving in her grave many floors below. Other stories by Poe such as Rats in the Wall and The Tell-Tale Heart give more evidence that he was well acquainted with the symptoms of central sensitization syndrome.
HOW THE DEFINITION HAS EVOLVED
To recognize fibromyalgia we need an accurate definition, which has evolved over the years. If we don’t know where we’ve been, it is difficult to understand where we are now or how we got here.
Gowers,10 in 1904, was the first to describe diffuse pain as “fibrositis.” He believed that the pain was due to proliferation or inflammation (or both) of subcutaneous and fibrous tissue, a histopathology that has not been satisfactorily demonstrated to this date. Unfortunately for our purposes, his paper was a descriptive essay that made no attempt at codification. In fact, attempts to clinically define and classify fibromyalgia syndrome have been relatively recent.
Hench11 proposed the first clinical definition in 1976, and it probably did more harm than good. His criteria were two: pain, and no physiologic explanation. The diagnosis was therefore made by ruling out everything else rather than by ruling it in by clinical criteria. Consequently, the diagnosing physician had to investigate the symptom or symptoms by ordering potentially limitless testing, which all had to be normal before the diagnosis could be entertained. I continue to see this phenomenon today as new patients with classic fibromyalgia syndrome arrive carrying reports of normal magnetic imaging of the entire body and serologic testing—a “connective tissue disease workup.”