Purpose: The present study aimed to investigate the proportion of myofascial pain syndrome (MPS) among patients with definitively diagnosed or suspected fibromyalgia (FM), and to compare patients ultimately diagnosed with MPS and those diagnosed with FM, as well as to describe the clinical characteristics of the MPS group. Patients and Methods: This retrospective cross-sectional study was conducted at a university hospital. Clinical data were retrospectively extracted from electronic medical records of patients referred with suspected or diagnosed FM between January 2018 and December 2022. Available clinical information was limited to routinely documented data in referral documents and medical records. Patients included those definitively diagnosed with FM, as well as those suspected of FM based on established criteria or on the opinion of a rheumatologist or an FM expert. Final diagnoses were reassessed by one of the authors, who reviewed the original documentation to assess reclassification as MPS, based on regional pain, myofascial trigger points, and taut bands of muscle fibers. Results: A total of 29 patients were identified as potentially eligible, and 28 were included in the final analysis (mean age, 48.8 years; 28.6% male). Of the 29 patients, 25 (86.2%) were ultimately diagnosed with MPS. Compared with the FM group, the MPS group was older, responded better to local treatments, and reported less fatigue. A substantial proportion of patients with MPS had upper back pain and chronic widespread pain. Conclusion: In this retrospective record-based study, most patients with diagnosed or suspected FM were ultimately diagnosed with MPS. Although several clinical features distinguished MPS from FM, patients in the MPS group in this referral-based cohort frequently exhibited upper back pain and chronic widespread pain, features typically associated with FM, which may contribute to diagnostic confusion. Careful physical examination and assessment of response to local treatments may improve diagnostic accuracy. Keywords: chronic widespread pain, differential diagnosis, fibromyalgia, myofascial pain syndrome
Hadano et al. (Fri,) studied this question.