Bilaterally Reduced Intraepidermal Nerve Fiber Density in Unilateral CRPS-I

• Published in: Pain medicine (Malden, Mass.) Mass.), 2018-10, Vol.19 (10), p.2021-2030
• Main Authors: Rasmussen, Vinni F, Karlsson, Páll, Drummond, Peter D, Schaldemose, Ellen L, Terkelsen, Astrid J, Jensen, Troels S, Knudsen, Lone F
• Format: Article
• Language: English
• Subjects: Adult; Cold; Cold stimuli; Cold Temperature; Complex regional pain syndrome; Complex regional pain syndromes; Complications and side effects; Development and progression; Epidermis; Epidermis - innervation; Epidermis - pathology; Epidermis - physiopathology; Erythromelalgia; Female; Health aspects; Heat; Hot Temperature; Humans; Hyperesthesia - pathology; Hyperesthesia - physiopathology; Limbs; Male; Measurement; Middle Aged; Nerve Fibers - pathology; Neurofibrils; Neuropathy; Pain; Pain management; Pain perception; Pain Threshold; Physiological aspects; Reflex Sympathetic Dystrophy - pathology; Reflex Sympathetic Dystrophy - physiopathology; Risk factors; Skin; Skin - innervation; Skin - pathology; Skin - physiopathology; Thermal stimuli; Trauma; Young Adult
• ISSN: 1526-2375; 1526-4637
• DOI: 10.1093/pm/pnx240

Abstract Objective Findings regarding small nerve fiber damage in complex regional pain syndrome type I (CRPS-I) are not uniform, and studies have not included a matched healthy control group. The aim was to assess intraepidermal nerve fiber density (IENFD) in relation to thermal sensitivity of the same skin areas in CRPS-I patients and a gender- and age-matched healthy control group. Methods IENFD was investigated in skin biopsies from the CRPS-affected and contralateral limbs of eight CRPS-I patients and from an equivalent site in eight gender- and age-matched healthy controls (HCs). Thermal thresholds (cold/warm detection, cold- and heat-pain detection) were assessed on the affected limb, the matching contralateral limb, and on the equivalent limbs of HCs, and participants rated the intensity of cold/heat and pain to static thermal stimuli (5 °C and 40 °C). Results IENFD was significantly lower in both the affected and contralateral limbs of CRPS-I patients than HCs, but IENFD did not differ between the affected and contralateral limbs of patients. The heat pain threshold was lower in the affected CRPS-I limb than in HCs, but all other thermal thresholds were similar in both groups. CRPS-I patients rated the cold stimulus as colder and more painful in the affected limb, and the warm stimulus as hotter, bilaterally, than the HCs. Conclusions CRPS-I may be associated with bilateral small fiber damage, and perhaps small fiber neuropathy and bilateral disturbances in thermo-sensory perception. These disturbances could stem from a systemic response to injury or might increase the risk of developing CRPS-I after physical trauma.