Pain
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Medication-overuse headache (MOH) is relatively common, but its incidence has not been calculated and there are no prospective population-based studies that have evaluated risk factors for developing MOH. The aim of this study was to estimate incidences of and identify risk factors for developing chronic daily headache (CDH) and MOH. This longitudinal population-based cohort study used data from the Nord-Trøndelag Health Surveys performed in 1995-1997 and 2006-2008. ⋯ In contrast, these factors did not increase the risk of CDHwoO. In this large population-based 11-year follow-up study, several risk factors for MOH did not increase the risk for CDHwoO, suggesting these are pathogenetically distinct. If the noted associations are causal, more focus on comorbid condition, physical activity, and use of tobacco and tranquilizers may limit the development of MOH.
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Randomized Controlled Trial Multicenter Study
The CONECSI trial: results of a randomized controlled trial of a multidisciplinary cognitive behavioral program for coping with chronic neuropathic pain after spinal cord injury.
Many people with spinal cord injury (SCI) rate chronic neuropathic pain as one of the most difficult problems to manage. The aim of the CONECSI (COping with NEuropathiC Spinal cord Injury pain) trial was to evaluate a multidisciplinary cognitive behavioral treatment program for persons with chronic neuropathic pain after SCI. The intervention consisted of educational, cognitive, and behavioral elements. ⋯ Significant intervention effects (Time*Group interactions) were found for anxiety and participation in activities, but not for the primary outcomes. Subsequent paired t tests showed significant changes in the intervention group that were not seen in the control group: decrease of pain intensity, pain-related disability, anxiety, and increase of participation in activities. This study implies that a multidisciplinary cognitive behavioral program might have beneficial effects on people with chronic neuropathic SCI pain.
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Chemokine signaling is important in neuropathic pain, with microglial cells expressing CCR2 playing a well-established key role. DAPTA, a HIV gp120-derived CCR5 entry inhibitor, has been shown to inhibit CCR5-mediated monocyte migration and to attenuate neuroinflammation. We report here that as a stabilized analog of DAPTA, the short peptide RAP-103 exhibits potent antagonism for both CCR2 (half maximal inhibitory concentration [IC50] 4.2 pM) and CCR5 (IC50 0.18 pM) in monocyte chemotaxis. ⋯ RAP-103 relieves behavioral hypersensitivity, probably through either or both CCR2 and CCR5 blockade, because by using genetically deficient animals, we demonstrated that in addition to CCR2, CCR5 is also required for the development of neuropathic pain. Moreover, RAP-103 is able to reduce spinal microglial activation and monocyte infiltration, and to inhibit inflammatory responses evoked by peripheral nerve injury that cause chronic pain. Our findings suggest that targeting CCR2/CCR5 should provide greater efficacy than targeting CCR2 or CCR5 alone, and that dual CCR2/CCR5 antagonist RAP-103 has the potential for broad clinical use in neuropathic pain treatment.
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Most studies of chronic nerve compression focus on large nerve function in painful conditions, and only few studies have assessed potential changes in the function of small nerve fibers during chronic nerve compression and recovery from compression. Cutaneous pressure-induced vasodilation is a neurovascular phenomenon that relies on small neuropeptidergic fibers controlling the cutaneous microvasculature. We aimed to characterize potential changes in function of these small fibers and/or in cutaneous microvascular function following short-term (1-month) and long-term (6-month) nerve compression and after release of compression (ie, potential recovery of function). ⋯ Pressure-induced vasodilation was impaired following nerve compression and restored following nerve release; both impairment and restoration were strongly related to duration of compression. Small and large nerve fiber functions were less closely related to duration of compression. Our data therefore suggest that cutaneous pressure-induced vasodilation provides a non-invasive and mechanistic test of neurovascular function that gives direct information regarding extent and severity of damage during chronic nerve compression and recovery, and may ultimately provide a clinically useful tool in the evaluation of nerve injury such as carpal tunnel syndrome.