Collin Simon M, Nijs Jo, Meeus Mira, Polli Andrea, Willekens Barbara, Ickmans Kelly
School of Social & Community Medicine, University of Bristol, Bristol, UK.
Pain in Motion Research Group (www.paininmotion.be); Department of Human Physiology and Physiotherapy, Faculty of Physical Education & Physiotherapy, Vrije Universiteit Brussel, Brussels, Belgium; Department of Physical Medicine and Physiotherapy, University Hospital Brussels, Brussels, Belgium.
Pain Physician. 2017 May;20(4):E489-E497.
Commonalities in the core symptoms of fatigue and cognitive dysfunction experienced by chronic fatigue syndrome (CFS, also known as ME) and multiple sclerosis (MS) patients have been described. Many CFS and MS patients also experience chronic pain, which has been attributed to central sensitization in both groups of patients. However, the characteristics of pain in CFS and MS patients have not been compared.
To compare experimental pain measurements in patients with CFS or MS and healthy controls.
Observational study.
This study took place in Belgium at Vrije Universiteit Brussel and the University of Antwerp.
Pressure pain thresholds, temporal summation, conditioned pain modulation, and occlusion cuff pressure thresholds rated as painful (1st cuff pressure threshold) and as 3/10 on a verbal numerical scale (2nd cuff pressure threshold) were measured in patients with CFS (n = 48), MS (n = 19) and healthy pain-free controls (n = 30). Adjusted between-group differences were estimated using linear regression models.
Finger pain pressure thresholds of patients with CFS, compared with patients with MS, were 25% lower (difference ratio 0.75 [95% CI 0.59, 0.95], P = 0.02) and shoulder pain pressure thresholds were 26% lower (difference ratio 0.74 [0.52, 1.04], P = 0.08). Compared with patients with MS, patients with CFS had 29% lower first cuff pressure threshold (difference ratio 0.71 [0.53, 0.94], P = 0.02) and 41% lower 2nd cuff pressure threshold (0.59 [0.41, 0.86], P = 0.006). Finger temporal summation was higher in patients with CFS than in patients with MS (mean difference 1.15 [0.33, 1.97], P = 0.006), but there were no differences in shoulder temporal summation or conditioned pain modulation at either site. Differences between patients with CFS and MS tended to be greater than between either patient group and healthy controls. Pain pressure thresholds and cuff pressure thresholds tended to be positively correlated, and temporal summation negatively correlated, with higher physical function and lower fatigue in both groups of patients. Subjective pain in patients with CFS but not in patients with MS was strongly negatively correlated with pain pressure thresholds and cuff pressure thresholds, and positively correlated with temporal summation.
The main limitations of our study are the relatively small sample sizes, its cross-sectional design, and its exploratory nature.
We found differences in the characteristics of pain symptoms reported by patients with CFS and patients with MS, which suggest different underlying mechanisms. Specifically, overactive endogenous pain facilitation was characteristic of pain in patients with CFS but not in patients with MS, suggesting a greater role for central sensitization in CFS.
慢性疲劳综合征（CFS，也称为肌痛性脑脊髓炎）和多发性硬化症（MS）患者经历的疲劳和认知功能障碍的核心症状存在共性。许多CFS和MS患者还患有慢性疼痛，这在两组患者中都归因于中枢敏化。然而，CFS和MS患者疼痛的特征尚未进行比较。
比较CFS或MS患者与健康对照的实验性疼痛测量结果。
观察性研究。
本研究在比利时的布鲁塞尔自由大学和安特卫普大学进行。
对48例CFS患者、19例MS患者和30例无疼痛的健康对照测量压力疼痛阈值、时间总和、条件性疼痛调制以及被评定为疼痛的袖带压力阈值（第一袖带压力阈值）和在语言数字量表上为3/10的袖带压力阈值（第二袖带压力阈值）。使用线性回归模型估计组间调整差异。
与MS患者相比，CFS患者的手指疼痛压力阈值低25%（差异比0.75[95%CI0.59，0.95]，P=0.02），肩部疼痛压力阈值低26%（差异比0.74[0.52，1.04]，P=0.08）。与MS患者相比，CFS患者的第一袖带压力阈值低29%（差异比0.71[0.53，0.94]，P=0.02），第二袖带压力阈值低41%（0.59[0.41，0.86]，P=0.006）。CFS患者的手指时间总和高于MS患者（平均差异1.15[0.33，1.97]，P=0.006），但在两个部位的肩部时间总和或条件性疼痛调制方面没有差异。CFS和MS患者之间的差异往往大于任何一组患者与健康对照之间的差异。两组患者的疼痛压力阈值和袖带压力阈值往往呈正相关，时间总和呈负相关，身体功能越高，疲劳越低。CFS患者的主观疼痛与疼痛压力阈值和袖带压力阈值呈强烈负相关，与时间总和呈正相关，而MS患者则不然。
我们研究的主要局限性是样本量相对较小、横断面设计及其探索性。
我们发现CFS患者和MS患者报告的疼痛症状特征存在差异，这表明潜在机制不同。具体而言，内源性疼痛易化过度活跃是CFS患者疼痛的特征，而MS患者则不是，这表明中枢敏化在CFS中起更大作用。
