Why It Hurts The Mechanisms of Pain in Rheumatoid Arthritis

? Rheumatoid arthritis-related inflammation can reduce the threshold for nociceptors to transmit action potentials, resulting in increased pain sensitivity or hyperalgesia. ? In addition to articular processes, spinal ,and supraspinal processes may play an important role in the modulation of pain in rheumatoid arthritis. ? Immune-mediated processes in rheumatoid arthritis may sensitize the nervous system even before joint inflammation is detected, and this may persist despite the resolution Pain is an important manifestation of inflammation, because inflammatory cytokines and mediators activate and sensitize primary afferent neurons.1 It should thus not be surprising that pain is nearly a universal feature of rheumatoid arthritis (RA), particularly in those experiencing a flare of the disease. However, ongoing and/or severe inflammation may not suffice to explain pain in some patients with low disease activity who would otherwise be considered to be in remission. It has been noted that up to 40% of patients with RA are regular users of opioid medications,2,3 with an increase noted in recent years.2 Although targeted therapies have significantly improved our ability to treat the underlying inflammatory processes and their complications, pain management options have not increased proportionally. Traditionally, pain in RA was presumed to be primarily driven by peripheral inflammation. One of the first mentions of inflammatory pain was suggested by a 1965 study conducted by Fremont-Smith and Bayles.4 In this study, the anti-inflammatory effect of acetylsalicylic acid was of greater therapeutic importance than its concurrent analgesic effect in a study of 12 patients with RA who reported improvement in ring size,

Automated summary

Inflammation in rheumatoid arthritis can increase pain sensitivity, immune-mediated processes may sensitize the nervous system before joint inflammation is detected, and pain is a common feature in rheumatoid arthritis.