Fibromyalgia Differential Diagnoses

Updated: Jul 26, 2023
  • Author: Chad S Boomershine, MD, PhD, CPI, CPT; Chief Editor: Herbert S Diamond, MD  more...
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Diagnostic Considerations

Although no basis for many of the multiple symptoms of patients with fibromyalgia will be found upon physical examination or laboratory testing, the physician must remain alert for organic illness (eg, colon carcinoma in a patient with irritable bowel syndrome).

The clinical assessment may reveal objective evidence for a discrete illness, such as hypothyroidism, rheumatoid arthritis (RA), systemic lupus erythematosus (SLE), polymyalgia rheumatica, or another inflammatory or autoimmune disorder. Such findings do not exclude comorbid fibromyalgia. Indeed, approximately 25% of patients with RA and approximately 50% of patients with SLE also have fibromyalgia, and the provision of optimum care in such cases impels recognition and treatment of both illnesses.

It is important to recognize that treatment of an autoimmune disorder in a patient with comorbid fibromyalgia usually does not improve fibromyalgia symptoms. Recognition and treatment of fibromyalgia in these patients is vitally important to avoid overtreatment with immunosuppressive drugs, which can result when providers falsely ascribe symptoms of fibromyalgia to the autoimmune condition.

Other problems to consider in the differential diagnosis of fibromyalgia include the following:

  • Atypical chest pain
  • Chronic fatigue syndrome
  • Multiple chemical sensitivity
  • Sick building syndrome
  • Vulvodynia
  • Vulvar vestibulitis

Because complaints of chest pain, shortness of breath, and palpitations are common, serious cardiac problems should be considered and may require extensive evaluation. Many symptoms in patients with fibromyalgia can be related to mitral valve prolapse syndrome.

Fibromyalgia Rapid Screening Tool

 A self-administered questionnaire developed by French researchers, the Fibromyalgia Rapid Screening Tool (FiRST) consists of six questions regarding the presence or absence of the following dimensions of fibromyalgia:

  • Widespread pain
  • Fatigue
  • Pain characteristics
  • Nonpainful abnormal sensations
  • Functional somatic symptoms
  • Sleep and cognitive problems

Questions require only a "yes" or "no" answer, with each "yes" answer worth 1 point. A score of 5 or more has the highest sensitivity and specificity for fibromylagia. [102]

Although initially used only to discriminate between fibromyalgia and other painful conditions, FiRST has also proved useful in helping detect concomitant fibromyalgia in patients with inflammatory rheumatic disorders. In a study of patients presenting for treatment of rheumatoid arthritis, spondyloarthritis, or connective tissue disease, and whose pain had persisted for at least 3 months, FiRST screening detected concomitant fibromyalgia in 143 of 586 patients (24.4%). [102]

By comparison, use of American College of Rheumatology 1990 criteria detected only 52 cases of fibromyalgia (8.6%), and assessment by a rheumatologist, 93 cases (15.4%). The study authors conclude that FiRST can be used by rheumatologists in clinical practice to rule out fibromyalgia as a possible explanation for apparent treatment failure in other rheumatologic disorders. [102]

Differential Diagnoses