AB1551 IMAGING OF THE PERIPHERAL NERVOUS SYSTEM IN NOCIPLASTIC PAIN: AN ULTRASOUND STUDY IN PATIENTS WITH FIBROMYALGIA

• Published in: Annals of the rheumatic diseases Vol. 82; no. Suppl 1; p. 2009
• Main Authors: DI Carlo, M., Bianchi, B., Cipolletta, E., Farah, S., Filippucci, E., Salaffi, F.
• Format: Journal Article
• Language: English
• Published: Kidlington BMJ Publishing Group Ltd and European League Against Rheumatism 01.06.2023; Elsevier B.V; Elsevier Limited
• Subjects: Autonomic nervous system; Fatigue; Fibromyalgia; Imaging; Nervous system; Neuroimaging; Pain; Peripheral nerves; Peripheral neuropathy; Scientific Abstracts; Spinal cord; Sural nerve; Ultrasonic imaging; Ultrasound; Vagus nerve; Ultrasound; Imaging; Pain
• ISSN: 0003-4967; 1468-2060
• DOI: 10.1136/annrheumdis-2023-eular.3001

BackgroundFibromyalgia (FM) is a condition mainly characterized by the presence of chronic widespread musculoskeletal pain, fatigue, and sleep alterations. The pathophysiological basis of FM has not yet been clarified. It is widely recognized that FM is a condition characterized by the presence of central sensitization. The mechanisms of centralized pain have been studied mainly through functional imaging techniques. However, over the past decade, evidence of peripheral nervous system involvement has emerged alongside pathophysiological mechanisms involving the brain and spinal cord and a detailed analysis of the morphostructural abnormalities of other nerves in FM patients is still lacking.ObjectivesTo investigate the sonographic changes [i.e., increased cross-sectional area (CSA)], of peripheral nerves in patients with FM compared to healthy controls and to identify potential clinical correlations associated with increased CSA in patients with fibromyalgia.MethodsConsecutive female patients with FM included in this cross-sectional observational study underwent sonographic assessment using a standardised scanning protocol. The CSA of 7 nerves was measured bilaterally at 11 anatomic sites by an experienced sonographer. Differences in CSA of nerves were compared with those of healthy subjects by one-way analysis of variance. Patients underwent clinimetric evaluation aimed at investigating disease severity, neuropathic pain features, depression, anxiety, fatigue, and autonomic symptoms to explore the possible correlation between CSA and clinical features.Results47 patients and 20 healthy controls were enrolled. Differences in terms of increased CSA between patients and healthy controls were identified at multiple levels, mainly at the level of the sural nerve, vagus nerve and 6th cervical nerve root (for all, p < 0.001). Sonographic findings, however, did not correlate with the clinical features explored.Table 1.Mean cross-sectional area values (mm2) of individual nerve scans in healthy controls and fibromyalgia patients.Healthy controls (n 20)Patients (n 47)MeanSDMeanSD6th cervical root right3.950.755.911.526th cervical root left3.900.645.781.36Median distal right8.000.978.551.62Median distal left8.100.968.361.84Median proximal right6.951.468.512.30Median proximal left7.201.398.482.26Fibular right9.102.449.952.27Fibular left9.352.5810.292.21Sural right2.700.574.681.56Sural left2.850.584.421.09Tibial distal right11.352.4713.893.49Tibial distal left11.402.7013.763.44Tibial proximal right13.552.5815.363.26Tibial proximal left13.952.6615.124.03Ulnar proximal right6.151.346.551.80Ulnar proximal left6.001.076.481.79Vagus right2.750.784.080.85Vagus left2.850.743.910.90ConclusionPatients with FM show higher CSA of nerves than healthy subjects. The increased CSA is most evident at the sural nerve, vagus nerve and 6th cervical nerve root. Ultrasound, a relatively easy-to-use technique, could identify morphological changes, in peripheral nervous structures in patients with FM.References[1]Caro XJ et al. Arthritis Rheumatol 2014; 66: 1945-1954. doi: 10.1002/art.38662.[2]Littlejohn G. Nat Rev Rheumatol 2015; 11: 639-648. doi: 10.1038/nrrheum.2015.100.[3]Di Carlo M et al. Clin Exp Rheumatol 2021; 39 Suppl 130: 102-107. doi: 10.55563/clinexprheumatol/r0kho4.[4]Goebel A et al. J Clin Invest 2021; 131: e144201. doi: 10.1172/JCI144201.[5]Kerasnoudis A et al. J Neuroimaging 2015; 25: 528-538. doi: 10.1111/jon.12261.Acknowledgements:NIL.Disclosure of InterestsNone Declared.