Fibromyalgia is not a muscle disorder

Area of Science:

• Rheumatology
• Neurology
• Pain Medicine

Background:

• Fibromyalgia was historically misclassified as a muscle disorder, often termed 'fibrositis'.
• Numerous studies have explored potential muscle pathology as the cause of fibromyalgia symptoms.
• Early research faced significant methodological limitations, impacting findings on muscle involvement.

Purpose of the Study:

• To critically evaluate the evidence for muscle pathology in fibromyalgia.
• To determine the underlying basis of fibromyalgia: central, peripheral, or muscular.
• To synthesize findings from muscle tissue examination and tenderness studies.

Main Methods:

• Review of methodologically sound studies examining muscle tissue in fibromyalgia patients.
• Analysis of data from studies investigating tenderness thresholds.
• Comparison of findings from early versus recent research methodologies.

Main Results:

• Initial studies suggested muscle abnormalities, but were often methodologically flawed.
• More recent, rigorous studies demonstrate normal muscle tissue in fibromyalgia patients.
• Combined evidence points away from a peripheral or muscular origin for fibromyalgia.

Conclusions:

• Fibromyalgia is best characterized as a chronic pain syndrome.
• The evidence strongly supports a central nervous system basis for fibromyalgia.
• Current research refutes a primary muscular etiology for fibromyalgia.