Differential Diagnosis of Myofascial Pain Syndrome and Fibromyalgia

SUMMARY

Objectives: This review examines diagnostic factors of myofascial pain syndrome [MPS] and fibromyalgia [FMS], and their differential diagnosis.

Findings: A base of electrophysiologic and anatomic data exists that supports the clinical identification of myofascial trigger point [TrP] features. Included are electrical characteristics of the TrP, visualization of the taut band and strong support for a model of the TrP. The widespread nature of chronic MPS mimics FMS. Fibromyalgia has been found to be associated with a host of clinical and biochemical markers. Objective markers besides widespread tenderness are needed to distinguish FMS from other conditions. It is not clear if either response to electrical stimulation of the parietal tissues or the skin rolling test will provide the necessary specificity. Biochemical markers such as substance P elevation in spinal fluid may be sensitive for FMS, but the specificity of the finding is unknown. The possibility is raised that some findings may be related to the severity of chronic widespread pain, and non-specific.

Conclusion: A variety of clinical tests are available to assess both MPS and FMS. However, tests that are based primarily on the identification of widespread tenderness will over-diagnose FM, and under-diagnose MPS, and may miss other causes of chronic myalgia.

KEYWORDS:

• Myofascial pain
• fibromyalgia
• pain
• diagnosis
• myalgias