Pain
-
Radiographic knee osteoarthritis (OA) is a highly prevalent condition that has been the focus of a number of studies identifying factors that are prognostic of continued or worsening pain and function. Although prior prognostic studies have identified a number of demographic, physical, and psychological factors that are predictive of outcome, minimal focus has been placed on pain coping skills as prognostic factors, despite cross-sectional evidence suggesting that pain coping skills are associated with pain and function in knee OA. The present study reports on the use of pain coping skills as prognostic factors for changes in pain and/or function over a 1-year period. ⋯ Data from the Coping Strategies Questionnaire were compared against 1-year change in pain, function, or both, using established criteria for defining whether the patient got better, worse, or stayed the same over the 1-year period. Results revealed a significant effect for praying/hoping, increased behavioral activities, and pain catastrophizing as prognostic of pain outcomes; ignoring pain and praying/hoping were prognostic of function outcomes; and increased behavioral activities and pain catastrophizing were prognostic of a combined pain and function outcome. The findings provide important new evidence regarding the potential clinical relevance of a number of pain coping responses hypothesized to influence future pain and function in persons with arthritis.
-
Anti-nerve growth factor (anti-NGF) treatment is analgesic in chronic inflammatory pain conditions without reducing inflammation. Hypothesizing that ongoing pain induced by inflammatory mediators is increased by long term sensitization of nociceptors, we combined the non-inflammatory NGF-sensitization model with an inflammatory ultraviolet-B (UV-B) model in human volunteers. UV-B irradiation of the skin presensitized with NGF 3 weeks before intensified the pre-existing NGF hyperalgesia during the inflammatory phase of UV-B and caused spontaneous pain in about 70% of the subjects. ⋯ Hyperalgesia and spontaneous pain coexisted in NGF/UV-B treated skin but did not significantly correlate (r < -0.1 at day 1 and r < 0.2 at day 3). We conclude that NGF can sensitize nociceptive endings such that inflammatory mediators may cause sufficient excitation to provoke spontaneous pain. Our results suggest that neuronal sensitization and level of inflammation represent independent therapeutic targets in chronic inflammatory pain conditions.