Mechanisms of chronic pain in inflammatory rheumatism: the role of descending modulation.

ABSTRACT: Persistent pain despite satisfactory disease treatment is frequent in rheumatoid arthritis (RA) and spondyloarthritis (Spa) and may result from specific changes in central pain processing. We assessed these mechanisms further by systematically comparing thermal pain thresholds and conditioned pain modulation (CPM) between patients with active RA or Spa and healthy controls. We included 50 patients with RA and 50 patients with Spa and 100 age-matched and sex-matched controls. Heat and cold pain thresholds (HPT-CPT) were measured on the dominant forearm, and CPM was assessed by applying conditioning stimuli (immersion in a cold-water bath) to one foot and the nondominant hand in 2 successive randomized sequences. Descending pain modulation was assessed as the difference in HPTs (in °C) before and after conditioning. Larger HPT differences (ie, a larger CPM effect) reflected more efficient descending inhibition. Potential associations between changes in CPM and clinical data, including disease activity, pain intensity, and psychological and functional variables, were systematically assessed. Heat pain threshold and cold pain threshold were similar in patients and controls. The mean CPM effect was significantly weaker in patients than that in controls for conditioning applied to either the foot (0.25°C ±2.57 vs 2.79°C ±2.31; P < 0.001) or the nondominant hand (0.57°C ±2.74 vs 2.68°C ±2.12; P < 0.001). The smaller CPM effect in patients was correlated with average pain intensity, but not with disease activity or other clinical characteristics, suggesting a significant pathophysiological role for changes in endogenous pain modulation in the mechanisms of chronic pain associated with inflammatory rheumatism.

"FastSchool": A single session of an interprofessional pain management program for chronic pain patients inspired by cognitive behavioral therapy.

OBJECTIVES: Multidisciplinary approaches to treating chronic pain have been proven effective. Currently, chronic pain patients face lengthy waitlists in pain medicine departments. To overcome this problem, we developed the "FastSchool" program to educate patients about pain management and treatment. In this study, we evaluated the benefit of a "FastSchool" session on pain and catastrophizing in chronic pain patients. METHODS: Included patients had chronic non-cancer pain, no more than 2 visits to a pain medicine department. Patients attended a single 3-hour session, conducted by an interprofessional team. Four topics were addressed: chronic pain mechanisms, pharmacological therapies, physical activity, and the management of analgesics. Patients completed questionnaires at baseline and at 3 months post-session to assess pain interference, pain intensity, and catastrophizing. RESULTS: The study population included 88 patients; 71 completed the follow-up questionnaires. Pain interference (p = 0.002), average pain intensity (p = 0.013), and catastrophizing (p < 0.001) decreased 3 months after FastSchool. At M3, 35 % of patients felt their pain had improved based on the Patient Global Impression of Change. CONCLUSION: FastSchool, an innovative short-term educational program inspired by cognitive behavioral therapy, showed positive results in reducing pain impact. PRACTICE IMPLICATIONS: Implementation of FastSchool in pain medicine departments would reduce waitlist times for non-pharmacological treatment.

Denosumab in active Charcot neuro-osteoarthropathy of the foot.

OBJECTIVE: Active Charcot Neuro-osteoarthropathy (CN) is a rare and severe complication of peripheral neuropathy that leads to deformity and disability. No pharmacological treatment is available. Increased osteoclastic activity plays a central role in active CN, particularly via receptor activator of nuclear factor ligand (RANK-L). We aimed to describe clinical, morphological and metabolic imaging effects of denosumab, a fully human monoclonal anti- RANK-L antibody, in active CN. METHODS: In this open-label study, we included all consecutive patients with active refractory CN treated with denosumab in our tertiary center. Baseline and follow-up assessment included clinical examination, biological and imaging procedures (morphological and metabolic) before and after treatment. RESULTS: Seven patients were treated with denosumab between 2017 and 2020 and followed for a median of 16 months [6-39]. All patients clinically improved, 4 further relapsed after a median of 4 months [3-33]. Four patients were retreated with the same efficacy. Imaging follow-up available in 5 patients showed stability of structural damage (radiography) and a significant decrease of metabolic activity (FDG PET-CT) in 4 of them. No adverse event or hypocalcemia was observed. CONCLUSION: In patients with refractory active CN, denosumab had a clinical effect, prevented bone and joint destruction, together with a metabolic effect, as assessed by FDG PET-CT. These results justify the conduction of a randomized controlled trial to assess the efficacy of denosumab in acute CN.