The efficacy of oral corticoids in treating complex regional pain syndrome: A retrospective cohort study

OBJECTIVES

There is growing evidence supporting the role of inflammatory mechanisms in complex regional pain syndrome (CRPS). Corticoids, as most effective anti-inflammatory drugs, are widely used in treating inflammation. The aim of this study was to retrospectively assess the efficacy of oral corticoid treatment in CRPS patients.

METHODS

Patients treated at the center of pain medicine in the Erasmus University Medical Centre between January 2015 and January 2020 were approached to partake in this study. Medical records were screened for age, gender, medical history, duration of CRPS, and CRPS severity score. Also, treatment effect, dose and duration, pain scores (NRS), and side effects were extracted from medical records. In addition, global perceived effect was completed in patients treated with corticoids.

RESULTS

Between January 2015 and January 2020, twenty-nine CRPS patients received corticoids and met the inclusion criteria. One extreme outlier was excluded and treatment effect was unknown for one patient. Average daily dose was 28.9 mg (range 10-30 mg) and the mean treatment duration was 10.5 days (7-21 days). Fourteen patients (51.9%) responded positively to treatment and thirteen (48.1%) did not respond. Side effects were reported in five patients (17.9%).

CONCLUSIONS

Corticoid treatment was effective in more than half of the patients. With only mild side effects reported the treatment also appears to be relatively safe. Further research is needed to investigate the efficacy of corticoids in treating (early) CRPS, preferably in an intervention study.

The effect of recorded music on pain endurance (CRESCENDo) - A randomized controlled trial

INTRODUCTION

Clarifying the effect of music on pain endurance in an experimental design could aid in how music should be applied during both surgical and non-surgical interventions. This study aims to investigate the effect of music on pain endurance and the involvement of the sympathetic adrenomedullary axis (SAM) and the hypothalamic-pituitary-adrenocortical axis (HPA).

MATERIALS AND METHODS

In this randomized controlled trial all participants received increasing electric stimuli through their non-dominant index finger. Participants were randomly assigned to the music group (M) receiving a 20-minute music intervention or control group (C) receiving a 20-minute resting period. The primary outcome was pain endurance, defined as amount milliampere tolerated. Secondary outcomes included anxiety level, SAM-axis based on heart rate variability (HRV) and salivary alpha-amylase, and HPA-axis activity based on salivary cortisol.

RESULTS

In the intention-to-treat analysis, the effect of music on pain tolerance did not statistically differ between the M and C group. A significant positive effect of music on pain endurance was noted after excluding participants with a high skin impedance (p = 0.013, CI 0.35; 2.85). Increased HRV was observed in the M-group compared to the C-group for SDNN (B/95%CI:13.80/2.22;25.39, p = 0.022), RMSSD (B/95%CI:15.97/1.64;30.31, p = 0.032), VLF (B/95%CI:212.08/60.49;363.67, p = 0.008) and HF (B/95%CI:821.15/150.78;1491.52, p = 0.0190). No statistical significance was observed in other secondary outcomes.

CONCLUSIONS

The effect of the music intervention on pain endurance was not statistically significant in the intention-to-treat analysis. The subgroup analyses revealed an increase in pain endurance in the music group after correcting for skin impedance, which could be attributed to increased parasympathetic activation.

Effectiveness of Infliximab in Patients with Complex Regional Pain Syndrome: A Case Series

Purpose

Complex regional pain syndrome (CRPS) is a multi-mechanism disease, with an exaggerated inflammatory response as an important underlying mechanism. Auto-inflammation can theoretically be combated by anti-inflammatories, such as TNF-α inhibitors. This study's aim was to assess the effectiveness of intravenous infliximab, a TNF-α inhibitor, in patients with CRPS.

Patients and Methods

CRPS patients treated with infliximab between January 2015 and January 2022 were approached to participate in this retrospective study. Medical records were screened for age, gender, medical history, CRPS duration, and CRPS severity score. Additionally, treatment effect, dose and duration, and side effects were extracted from medical records. Patients who still receive infliximab completed a short global perceived effect survey.

Results

Eighteen patients received infliximab, and all but two gave consent. Trial treatment with three sessions of 5 mg/kg intravenous infliximab was completed in 15 patients (93.7%). Eleven patients (73.3%) were categorized as responders with a positive treatment effect. Treatment was continued in nine patients, and seven patients are currently treated. Infliximab dose is 5 mg/kg, and frequency is every four to six weeks. Seven patients completed a global perceived effect survey. All patients reported improvement (median 2, IQR 1-2) and treatment satisfaction (median 1, IQR 1-2). One patient described side effects such as itching and rash.

Conclusion

Infliximab proved effective in 11 out of 15 CRPS patients. Seven patients are still being treated. Further research is needed on the role of infliximab in the treatment of CRPS and possible predictors of response to treatment.

Glucocorticoid treatment in patients with complex regional pain syndrome: A systematic review

BACKGROUND AND OBJECTIVE

The pathophysiology of complex regional pain syndrome (CRPS) is multifactorial, with an exaggerated inflammatory response being the most prominent. Treatment for CRPS is carried out according to the presenting pathophysiological mechanism. Anti-inflammatory treatment with glucocorticoids is therefore an option. The aim of this study was to systematically review the efficacy of glucocorticoids in CRPS.

DATABASES AND DATA TREATMENT

Embase, Medline, Web of Science and Google Scholar were systematically searched for articles focusing on glucocorticoid treatment and CRPS. Screening based on title and abstract was followed by full-text reading (including reference lists) to determine the final set of relevant articles. Bias was assessed using the revised Cochrane risk-of-bias-tool for randomized trials (Rob2).

RESULTS

Forty-one studies were included, which reported on 1208 CRPS patients. A wide variety of glucocorticoid administration strategies were applied, with oral being the most frequently chosen. Additionally, researchers found great heterogeneity in outcome parameters, including clinical symptoms, pain relief and range of motion. The use of glucocorticoids caused an improvement of parameters in all but two studies. In particular, improvement in pain relief and range of motion were reported. Using glucocorticoids in CRPS of longer duration (i.e. more than 3 months) appears to be less effective.

CONCLUSION

Based on the present review, there is evidence to support glucocorticoid treatment in CRPS. However, the ideal administration route and dose remain unclear. We therefore recommend future research via an intervention study, as well as studies on the aetiological mechanisms and corresponding optimal treatment because CRPS pathogenesis is only partially understood.

SIGNIFICANCE

Several studies point towards CRPS being an inflammatory response after tissue or nerve damage, with higher levels of pro-inflammatory cytokines in serum, plasma, cerebrospinal fluid and artificial skin blisters. Inflammation provides a possible role for glucocorticoids in treating CRPS. This systematic review provides a structured overview of glucocorticoid treatment in patients with CRPS. Improvement in pain and range of motion is shown. Systematic review registration number: PROSPERO-CRD42020144671.