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Relationship between sympathetic activity and pain intensity in fibromyalgia

1, 2, 3, 4, 5, 6, 7, 8, 9, 10

  1. Department of Physical Therapy, Federal University of Sao Carlos, Sao Carlos, Brazil.
  2. Internal Medicine, BIOMETRA Department, Humanitas Clinical and Research Centre, Rozzano, Italy.
  3. Internal Medicine, BIOMETRA Department, Humanitas Clinical and Research Centre, Rozzano, Italy.
  4. Internal Medicine, BIOMETRA Department, Humanitas Clinical and Research Centre, Rozzano, Italy.
  5. Emergency Medicine, Legnano Hospital, Legnano, Italy.
  6. IRCCS Galeazzi Orthopaedic Institute, Milan, Italy.
  7. Department of Anesthesia and Intensive Care Unit, Humanitas Clinical and Research Centre, Rozzano; and Department of Electronics Information and Bioengineering, Politecnico di Milano, Milan, Italy.
  8. Department of Rheumatology, L. Sacco Hospital, Milan, Italy.
  9. Department of Biomedical Sciences for Health, IRCCS Galeazzi Orthopaedic Institute, Milan; and University of Milan, Milan, Italy.
  10. Internal Medicine, BIOMETRA Department, Humanitas Clinical and Research Centre, Rozzano; and University of Milan, Milan, Italy.

Department of Physical Therapy, Federal University of Sao Carlos, Sao Carlos, SP, Brazil.

CER8315 Submission on line
2015 Vol.33, N°1 ,Suppl.88 - PI 0053, PF 0057
Full Papers

Rheumatology Article

 

Abstract

OBJECTIVES:
Fibromyalgia (FM) is a syndrome characterised by chronic musculoskeletal pain, hyperalgesia on specific areas of tenderness (tender points) and by an autonomic nervous system dysfunction consistent with sympathetic overactivity. It is not known whether there is any relationship between the amount of cardiovascular sympathetic activity and the magnitude of pain. Our objective was to assess this potential relationship in patients with FM.
METHODS:
Electrocardiogram, finger blood pressure, respiration and post-ganglionic sympathetic discharge activity (muscle sympathetic nerve activity, MSNA) were continuously recorded at rest in 25 patients with primary FMS. The autonomic profile was assessed by MSNA and spectral indices of cardiac sympathetic (LFRR) and vagal (HFRR) modulation and of sympathetic vasomotor control (LF-SAP) computed by spectrum analysis of RR and systolic arterial pressure (SAP) variability. Cardiac baroreflex function was evaluated by the index α (αLF). Baroreceptor modulation of the sympathetic vasomotor control (sBRS) was assessed by the MSNA/diastolic pressure relationship.
RESULTS:
Pain intensity was linearly correlated with LFRR/HFRR (r2=0.21; p=0.03), LFSAP (r2=0.26; p=0.02) and MSNA (burst rate) (r2=0.45; p=0.003). Pain intensity was inversely correlated with the αLF index (r2=0.24; p=0.02) and the sBRS (r2=0.28; p=0.03). Thus, the higher the sympathetic drive to the heart and vessels, the higher the magnitude of chronic pain. Also, the gains of both the cardiac and MSNA baroreceptor control were inversely related to the pain intensity.
CONCLUSIONS:
These findings raise the theoretical possibility that in FM patients the use of anti-adrenergic agents might lessen chronic pain intensity by reducing the underlying excessive sympathetic activity.

PMID: 25786044 [PubMed]

Received: 25/01/2015 - Accepted : 03/02/2015 - In Press: 18/03/2015 - Published: 18/03/2015