Enhanced reactivity to pain in patients with rheumatoid arthritis.
BACKGROUND
Maladaptive physiological responses to stress appear to play a role in chronic inflammatory diseases such as rheumatoid arthritis (RA). However, relatively little stress research in RA patients has involved the study of pain, the most commonly reported and most impairing stressor in RA. In the present study, we compared psychophysical and physiological responses to standardized noxious stimulation in 19 RA patients and 21 healthy controls.


METHODS
Participants underwent a single psychophysical testing session in which responses to a variety of painful stimuli were recorded, and blood samples were taken at multiple time points to evaluate the reactivity of cortisol, interleukin-6 (IL-6), and tumor necrosis factor-alpha (TNF-alpha) to the experience of acute pain.


RESULTS
The findings suggest that RA patients display a fairly general hyperalgesia to mechanical and thermal stimuli across several body sites. In addition, while serum cortisol levels did not differ at baseline or following pain testing in patients relative to controls, the RA patients tended to show elevations in serum IL-6 and demonstrated enhanced pain-reactivity of serum levels of TNF-alpha compared with the healthy controls (P < 0.05).


CONCLUSIONS
These findings highlight the importance of pain as a stressor in RA patients and add to a small body of literature documenting amplified responses to pain in RA. Future studies of the pathophysiology of RA would benefit from the consideration of acute pain levels when comparing RA patients with other groups, and future trials of analgesic interventions in RA patients may benefit from evaluating the effects of such interventions on inflammatory activity.
Edwards
Robert R
RR
Department of Anesthesiology, Harvard Medical School, Brigham & Women's Hospital, Chestnut Hill, MA 02467, USA. RREdwards@partners.org
Wasan
Ajay D
AD
Bingham
Clifton O
CO
Bathon
Joan
J
Haythornthwaite
Jennifer A
JA
Smith
Michael T
MT
Page
Gayle G
GG
D000328:Adult; D001172:Arthritis, Rheumatoid / Q000097:blood* / Q000503:physiopathology* / Q000523:psychology; D005260:Female; D006801:Humans; D006854:Hydrocortisone / Q000097:blood; D015850:Interleukin-6 / Q000097:blood; D008297:Male; D008875:Middle Aged; D010146:Pain / Q000097:blood* / Q000503:physiopathology* / Q000523:psychology; D010147:Pain Measurement / Q000379:methods*; D011795:Surveys and Questionnaires; D014409:Tumor Necrosis Factor-alpha / Q000097:blood
D015850:Interleukin-6; D014409:Tumor Necrosis Factor-alpha; D006854:Hydrocortisone