Diagnóstico de Fibromialgia

Fibromyalgia is a common cause of chronic musculoskeletal pain. It is one of a group of soft tissue pain disorders that affect muscles and soft tissues such as tendons and ligaments. None of these conditions is associated with tissue inflammation and the etiology of the pain is not known.
Fibromyalgia, like other functional somatic syndromes, has been a controversial illness. Patients look well, there are no obvious abnormalities on physical examination, and laboratory and radiologic studies are normal. Thus, the role of organic illness has been questioned, and fibromyalgia has often been considered to be psychogenic or psychosomatic. Current pathophysiologic concepts focus on alterations in central nervous system pain processing.
The diagnosis of fibromyalgia is based primarily on the patient's symptoms of widespread pain. Patients report chronic myalgias and arthralgias, but have no evidence of joint or muscle inflammation on physical examination or laboratory testing. The physical examination reveals multiple tender points at soft tissue locations. However, fibromyalgia can be diagnosed without a specific number of tender points



Laboratory testing — FM does not cause any abnormalities in laboratory testing or imaging. Thus, any testing is done primarily to exclude an associated disease or another illness that may mimic FM. We use the following approach to laboratory testing:
• We obtain a complete blood count (CBC) and an erythrocyte sedimentation rate (ESR) or a C-reactive protein (CRP), for initial laboratory evaluation. Since fibromyalgia is not an inflammatory condition, normal acute phase reactants immediately provide confidence that an occult inflammatory disorder is unlikely.
• Serologic tests, such as antinuclear antibody and rheumatoid factor, should be obtained only if the history and physical examination suggest an inflammatory, systemic rheumatic disease. These tests are often positive in otherwise healthy people and have very poor predictive value unless there is significant clinical suspicion of a systemic rheumatic disease.
• In patients with any suspicion of thyroid disease or inflammatory muscle disease we order thyroid function tests or a creatine kinase, respectively.
• There is no evidence that ordering viral tests such as antibodies to the Epstein-Barr virus or ordering vitamin D levels are helpful in the diagnosis of fibromyalgia
Additional evaluation — We obtain a careful history from all patients with FM to identify primary sleep or mood disorders. Patients should be questioned for symptoms of sleep apnea and repetitive limb movements; if the history is suggestive, patients should be referred for an overnight polysomnogram. Every FM patient should be questioned for symptoms of depression and anxiety, since at least one-third of FM patients have active mood disturbances at the time of their initial diagnosis. If a mood disorder is suspected, further evaluation and treatment by an expert experienced in these conditions is indicated.
2010 ACR preliminary diagnostic criteria: Some investigators have advocated not using the tender point examination as part of the FM diagnostic criteria and relying only on symptoms. This approach recognizes that most clinicians have not been trained in the technique for performing a tender point examination. Indeed, most rheumatologists make a diagnosis without a tender point examination. Furthermore, the tender points do not accurately reflect the underlying central pain pathophysiology involved in this disorder. These considerations were important in developing the 2010 American College of Rheumatology (ACR) preliminary diagnostic criteria for FM. These criteria provide an alternative approach to diagnosis, which does not require a tender point examination, but does provide a scale for measurement of the severity of symptoms that are characteristic of FM. These criteria were designed with the recognition that in practice, tender point counts are often not obtained, and the increased appreciation of the importance of cognitive problems and somatic symptoms in patients with FM that were not considered in the 1990 ACR classification criteria. The preliminary diagnostic criteria showed good correlation with the 1990 ACR criteria. The preliminary criteria may be used in patients with symptoms present at a similar level for at least three months, and no other disorder that would otherwise explain the pain. They combine a widespread pain index (WPI) and a symptom severity (SS) scale for making the diagnosis of FM (tabela abaixo). The WPI is a measure of the number of painful body regions from a defined list of 19 areas. The SS score includes an estimate of the degree of fatigue, waking unrefreshed, and cognitive symptoms; and the number of somatic symptoms in general. The SS can also be used for the assessment of patients with current or previous fibromyalgia or for longitudinal evaluation. A simple modification of the criteria allows them to be used in epidemiologic and clinical studies without an examiner.




Referências:
1- Clinical manifestations and diagnosis of fibromyalgia in adults. UpToDate. Acesso em 27 de junho de 2013.
2- Roberto Heymann. AtualizaDOR - Programa de Educação Médica em Ortopedia. Novos conceitos em fibromialgia. Escola Paulista de Medicina – Universidade Federal de São Paulo (EPM-UNIFESP).