What are the diagnostic criteria for Fibromyalgia (Fibromyalgia Syndrome)?

From the Guidelines

Fibromyalgia diagnosis should be based on clinical evaluation using the 2016 revised diagnostic criteria, which includes assessment of pain in multiple body regions using the Widespread Pain Index (WPI) and evaluation of symptom severity using the Symptom Severity Scale (SS), as recommended by the EULAR revised recommendations for the management of fibromyalgia 1. The diagnostic process for fibromyalgia involves a comprehensive assessment of pain, function, and psychosocial context, recognizing it as a complex and heterogeneous condition with abnormal pain processing and other secondary features 1. Key points to consider in the diagnosis of fibromyalgia include:

• Chronic widespread pain lasting at least three months
• Symptoms like fatigue, cognitive difficulties, and unrefreshing sleep
• Use of the WPI and SS to assess pain and symptom severity
• Ruling out other conditions that could explain the symptoms through targeted laboratory tests and physical examination
• Recognition of fibromyalgia as a central sensitization syndrome with abnormal pain processing 1. The EULAR revised recommendations for the management of fibromyalgia emphasize the importance of a multidisciplinary approach, combining non-pharmacological and pharmacological treatment modalities tailored to the individual patient's needs, with a focus on improving health-related quality of life and balancing benefit and risk of treatment 1. Some of the key recommendations for the diagnosis of fibromyalgia include:
• Laboratory and radiological exams to exclude treatable comorbidities, if needed 1
• Referral to other specialists, if necessary 1
• Use of a graduated approach to management, with initial focus on non-pharmacological therapies 1.

From the Research

Guidelines for Diagnosing Fibromyalgia

• The diagnosis of fibromyalgia requires that organic diseases are not causing the symptoms, and systemic and rheumatic diseases can be ruled out by a patient history, physical examination, and laboratory investigations 2.
• The 1990 American College of Rheumatology (ACR) classification criteria have been used in clinical settings, but they are not ideal for individual patient diagnosis, and clinicians should be aware of limitations inherent in using tender points in the diagnosis of fibromyalgia 2, 3.
• In 2010, the ACR proposed preliminary diagnostic criteria for fibromyalgia that abandoned the tender point count and placed increased emphasis on patient symptoms 3.
• A stepwise diagnostic work-up of patients with chronic widespread pain (CWP) in primary care is recommended, including:
  • Complete medical history including medication
  • Complete medical examination
  • Basic laboratory tests to screen for inflammatory or endocrinology diseases
  • Referral to specialists only in case of suspected somatic diseases
  • Assessment of limitations of daily functioning
  • Screening for other functional somatic symptoms and mental disorders
  • Referring to mental health specialists in case of mental disorder 3.
• The diagnosis of fibromyalgia is easy in most patients with CWP and does not ordinarily require a rheumatologist, but a rheumatologist's expertise might be needed to exclude difficult to diagnose or concomitant inflammatory rheumatic diseases 3.

Diagnostic Criteria and Tools

• The Fibromyalgia Survey Questionnaire (FSQ) can be used to assist physician's diagnosis of FMS 3.
• Screening questions based on published criteria can be used as a first approach in diagnosing functional illnesses 2.
• The American College of Rheumatology (ACR) classification criteria and the preliminary diagnostic criteria for fibromyalgia can be used to guide diagnosis 2, 3.

Challenges in Diagnosing Fibromyalgia

• The multiple symptoms of fibromyalgia often overlap with those of related disorders and may further complicate the diagnosis 2.
• One of the most challenging diagnostic dilemmas that clinicians face is distinguishing fibromyalgia from other central pain disorders (e.g., irritable bowel syndrome, chronic fatigue syndrome, migraine) 2.
• There is no "gold standard" for diagnosing fibromyalgia, and all diagnostic criteria should be interpreted with caution, considered rudimentary, and subject to modification 2.