Abstract
Increased cross-sectional area (CSA) of sural nerve, documented by ultrasound (US), has been revealed in small fibers neuropathy, condition present in about half of patients with fibromyalgia (FM). The aims of this study were to evaluate sural nerve CSA and to establish the variables associated with increased CSA in FM patients. A cross-sectional assessment was conducted in consecutive FM patients. Demographic data, clinimetric parameters [Fibromyalgia Impact Questionnaire (FIQR)], the neuropathic pain features [PainDetect Questionnaire (PDQ)], and the sural nerve CSA were recorded. CSA was determined by US, examining the sural nerve at the lateral region of the calf. CSA was compared with demographic and clinical variables. A multiple regression analysis was conducted applying CSA as dependent variable. One hundred and ten FM patients were enrolled. Sural nerve CSA showed a significant association with body mass index (BMI) (r = 0.422; p < 0.0001) and with PDQ (r = 0.361; p = 0.0001). The multiple regression analysis confirmed that BMI (p = 0.0001) and PDQ (p = 0.0028) were the two independent variables associated with CSA. The severity of the disease, measured with FIQR, showed no association. An increase in sural nerve CSA is closely related to BMI and to distinctive neuropathic symptoms. Overweight and obesity appear to be associated with a FM phenotype with documented peripheral nervous system involvement. Ultrasound examination of the sural nerve at calf level may reveal useful information in patients with FM, identifying a cluster of patients with peripheral nervous system alterations. This cluster of patients is generally overweight or obese, and complains of painful symptoms with neuropathic features.
Highlights
Fibromyalgia syndrome (FM) is a condition characterized by the presence of chronic widespread pain (CWP) associated with somatic symptoms, the latter mainly characterized by the presence of fatigue, memory impairment, and non-restorative sleep
Patients with known neurological diseases affecting the peripheral nervous system (PNS) or central nervous system (CNS), patients with internistic of rheumatological diseases that may lead to the involvement of the small nerve fibers, and patients with conditions that may interfere with clinical evaluation were excluded
In their interesting paper of 2015, Ebadi et al demonstrated that sural nerve cross-sectional area (CSA) was increased during small fibers neuropathy (SFN)
Summary
Fibromyalgia syndrome (FM) is a condition characterized by the presence of chronic widespread pain (CWP) associated with somatic symptoms, the latter mainly characterized by the presence of fatigue, memory impairment, and non-restorative sleep These symptoms are those that define FM according to the latest set of criteria proposed by the American College of Rheumatology (ACR) for diagnostic/classification purposes [1]. The presence of SFN can be demonstrated by histological examination performed on skin biopsy aimed at determining the intra-epidermal nerve fibers density (IENFD) or by examination of corneal innervation by confocal microscopy. Through the latter technique it has been demonstrated that alterations of the small fibers are present in about half of all FM patients [8]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
