Burgess Jamie, Marshall Anne, Rapteas Leandros, Riley David, Matsumoto Kohei, Boon Cheng, Alchawaf Alia, Ferdousi Maryam, Malik Rayaz A, Marshall Andrew, Kaye Stephen, Gosal David, Frank Bernhard, Alam Uazman
Institute of Life Course and Medical Sciences, University of Liverpool, Liverpool, UK.
Clinical Sciences Centre, Aintree University Hospital, Longmoor Lane, Liverpool, L9 7AL, UK.
Pain Ther. 2024 Dec;13(6):1541-1558. doi: 10.1007/s40122-024-00646-x. Epub 2024 Sep 12.
Painful idiopathic distal sensory polyneuropathy (IDSP) and fibromyalgia syndrome (FMS) are cryptogenic chronic pain syndromes. The contribution of small fibre pathology (SFP) in FMS remains controversial. This study aims to quantify small nerve pathology in participants with IDSP and FMS and identify relationships of SFP with sensory phenotypes.
In this study, 73 individuals (FMS: 25, IDSP: 23, healthy volunteers: 25) underwent comprehensive assessment, including neurological exams, questionnaires, sensory tests, and corneal confocal microscopy.
IDSP participants displayed lower wind-up ratio (WUR) relative to FMS (p < 0.001), loss of function to thermal and mechanical stimuli and elevated neuropathy disability scores compared to FMS and healthy volunteers (all p < 0.001). FMS participants demonstrated gain of function to heat and blunt pressure pain responses relative to IDSP, and healthy volunteers (heat: p = 0.002 and p = 0.003; pressure: both p < 0.001) and WUR (both p < 0.001). FMS participants exhibited reduced corneal nerve fibre density (p = 0.02), while IDSP participants had lower global corneal nerve measures (density, branch density, and length) relative to healthy volunteers (all p < 0.001). Utilising corneal nerve fibre length, SFP was demonstrated in 66.6% of participants (FMS: 13/25; IDSP: 22/23).
Participants with SFP, in both FMS and IDSP, reported symptoms indicative of small nerve fibre disease. Although distinctions in pain distributions are evident between individuals with FMS and IDSP, over 50% of participants between the two conditions displayed both a loss and gain of thermal and mechanical function suggestive of shared mechanisms. However, sensory phenotypes were associated with the presence of SFP in IDSP but not in FMS.
疼痛性特发性远端感觉性多发性神经病（IDSP）和纤维肌痛综合征（FMS）是原因不明的慢性疼痛综合征。小纤维病变（SFP）在纤维肌痛综合征中的作用仍存在争议。本研究旨在量化IDSP和FMS患者的小神经病变，并确定SFP与感觉表型之间的关系。
在本研究中，73名个体（FMS：25名，IDSP：23名，健康志愿者：25名）接受了全面评估，包括神经学检查、问卷调查、感觉测试和角膜共焦显微镜检查。
与FMS相比，IDSP患者的累积比率（WUR）较低（p<0.001），与FMS和健康志愿者相比，对热和机械刺激的功能丧失以及神经病变残疾评分升高（所有p<0.001）。与IDSP和健康志愿者相比，FMS患者对热和钝性压力疼痛反应的功能增强（热：p=0.002和p=0.003；压力：均p<0.001）以及WUR（均p<0.001）。FMS患者的角膜神经纤维密度降低（p=0.02），而与健康志愿者相比，IDSP患者的整体角膜神经测量值（密度、分支密度和长度）较低（所有p<0.001）。利用角膜神经纤维长度，66.6%的参与者存在SFP（FMS：13/25；IDSP：22/23）。
FMS和IDSP中患有SFP的参与者均报告了提示小神经纤维疾病的症状。虽然FMS和IDSP患者的疼痛分布明显不同，但这两种情况下超过50%的参与者表现出热和机械功能的丧失和增强，提示存在共同机制。然而，感觉表型与IDSP中SFP的存在相关，而与FMS无关。
