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The World Health Organization (WHO), in its last review of its International Classification of Diseases, established a new classification for chronic pain. Among the principal categories, of particular interest is chronic primary pain as a new type of diagnosis in those cases in which the etiology of the disease is not clear, being termed as chronic primary visceral pain when it is situated in the thorax, abdomen, or pelvis. Due to the novelty of the term, the objective of the systematic review was to examine the psychopathological and neuropsychological disorders associated with chronic primary visceral pain. We carried out a search of the scientific literature following the PRISMA directives using the Pubmed, Medline, PsycInfo and Scopus databases. A total of 33 articles were selected after applying the inclusion and exclusion criteria. The analysis of the studies showed that most persons with chronic primary visceral pain suffer from at least one psychological disorder; the most prevalent being anxiety, depressive or somatoform disorders. The most frequent psychopathological symptoms are anxiety, depression and somatization. Similarly, the findings are insufficient to determine the existence of deficits in the domains of executive functioning, memory and intelligence. However, the existence of attention biases does seem to be clear. This review supposes a starting point for conceptualizing chronic primary visceral pain. It is necessary to continue further research so as to obtain a better understanding of this pathology and the disorders associated.
Learn More >Chronic neuropathic pain (NP) frequently occurs after spinal cord injury (SCI) but lacks effective therapeutic options in the clinic. Numerous evidence indicates the involvement of macrophages activation in the NP, and the modulation of macrophages is promising for NP treatment. In this study, we introduce Cerium oxide nanoparticles (CONPs) and aim to investigate whether it can relieve the NP by modulating macrophage polarization.
Learn More >Abnormal angiogenesis and innervation in avascular discs during lumbar disc degeneration (LDD) cause severe back pain. These pathological alterations in the degenerating discs are induced by cytokines partially produced and secreted by inflammatory cells, among which macrophages are the most frequently ones detected at the legion site. However, the role of macrophages as well as their polarization in regulation of innervation and angiogenesis in the degenerating discs is unclear. In this study, we analyzed macrophages in the degenerating discs from patients and detected a specific macrophage subtype that expresses high levels of vascular endothelial growth factor A (VEGF-A). Co-expression of M2 macrophage markers in this macrophage subtype suggested that they were a M2d-like subtype. High levels of VEGF-A and genes associated with angiogenesis were also detected in LDD specimens compared to control heathy discs from a public database, consistent with our finding. Moreover, the levels of VEGF-A in disc macrophages were strongly correlated to the pain score of the examined patients, but not to the Thompson classification of the degeneration level of the patients. , overexpressing VEGF-A in macrophages increased the tube formation, proliferation and migration of co-cultured endothelial cells, and increased the innervation of embryonic spinal cord explant into the co-cultured area for macrophages and skeletal myocytes. , an orthotopic injection of adeno-associated virus carrying siRNA for VEGF-A under a macrophage-specific CD68 promoter significantly reduced the number of VEGF-A-positive disc macrophages and alleviated the pain in LDD-mice. Together, these data suggest that inhibition of angiogenetic potential of macrophages may reduce disc degeneration-associated pain through suppression of angiogenesis and innervation, as a promising therapy for LDD-associated pain.
Learn More >Data from 255 Thais with chronic pain were collected at Chiang Mai Medical School Hospital. After the patients self-rated their level of pain, a smartphone camera was used to capture faces for 10 s at a one-meter distance. For those unable to self-rate, a video recording was taken immediately after the move that causes the pain. The trained assistant rated each video clip for the pain assessment in advanced dementia (PAINAD). The pain was classified into three levels: mild, moderate, and severe. OpenFace was used to convert the video clips into 18 facial action units (FAUs). Five classification models were used, including logistic regression, multilayer perception, naïve Bayes, decision tree, k-nearest neighbors (KNN), and support vector machine (SVM). Out of the models that only used FAU described in the literature (FAU 4, 6, 7, 9, 10, 25, 26, 27, and 45), multilayer perception is the most accurate, at 50%. The SVM model using FAU 1, 2, 4, 7, 9, 10, 12, 20, 25, and 45, and gender had the best accuracy of 58% among the machine learning selection features. Our open-source experiment for automatically analyzing video clips for FAUs is not robust for classifying pain in the elderly. The consensus method to transform facial recognition algorithm values comparable to the human ratings, and international good practice for reciprocal sharing of data may improve the accuracy and feasibility of the machine learning's facial pain rater.
Learn More >Chronic pain (CP) prevalence in different studies has been inconsistent, ranging from 12% in Spain to 42% in the UK.
Learn More >Trigeminal Neuralgia – What Do We Know about the Causes, Diagnosis and Treatment? Classical trigeminal neuralgia is typically characterized by a stimulus-evoked, recurrent and intense short-lasting stabbing pain in the innervation area of the trigeminal nerve. Its intensity is among the most severe pain imaginable in humans, and yet it is often misdiagnosed and undertreated. Triggers are common activities of daily life like talking or eating. The classical trigeminal neuralgia is due to a neurovascular compression at the nerve root entry zone. The secondary form is related to an underlying neurological disease (caused for example by multiple sclerosis or compression by a brain tumor); the etiology of the idiopathic trigeminal neuralgia is unknown. Treatment options include both medication (mostly antiepileptic drugs) and escalated interventional approaches (microvascular decompression, neurolesional percutaneous procedures, neuromodulative therapeutic options and radiosurgery).
Learn More >As traumatic brain injury (TBI) is one of the major causes of permanent disability, there is increasing interest in the long-term outcome of TBI. While motor deficits, cognitive impairment and longer-term risks of neurodegenerative disease are well-established consequences in animal models of TBI, pain is discussed less often despite its high prevalence. The current study addresses the need to characterize the extent of chronic pain and long-term behavioral impairments induced by moderate lateral fluid percussion injury (latFPI) in mice up to 12 months post-TBI and evaluates the validity of the model. Adult male BALB/c mice were subjected to latFPI, and the results were compared with outcomes in sham-operated mice. Mouse behavior was assessed at 1 and 7 days and 1, 3, 6, 9, and 12 months post-injury using sensory-motor (neurological severity score, NSS), cold (acetone) and mechanical sensitivity (von Frey), depressive-like behavior (tail suspension), locomotor (open field), motor coordination (rotarod) and cognitive (Morris water maze, y-maze, passive avoidance) tests. Animals with TBI demonstrated significantly higher NSS than the sham-operated group for up to 9 months after the injury. Cold sensitization was significantly increased in the contralateral hind paw in the TBI group compared to that of the sham group at 3, 6, and 9 months after TBI. In the von Frey test, the withdrawal threshold of the contralateral and ipsilateral hind paws was reduced at 6 months after TBI and lasted for up to 12 months post-injury. latFPI induced progressive depressive-like behavior starting at 6 months post-injury. No significant deficits were observed in memory, motor coordination or locomotion over the 12-month assessment period. The present study demonstrates that moderate TBI in mice elicits long-lasting impairment of sensory-motor function, results in progressive depression and potentiates peripheral pain. Hence, the latFPI model provides a relevant preclinical setting for the study of the link between brain injury and chronic sequelae such as depression and peripheral pain.
Learn More >Predicting at-risk opioid use three months after ed visit for trauma: Results from the AURORA study.
Whether short-term, low-potency opioid prescriptions for acute pain lead to future at-risk opioid use remains controversial and inadequately characterized. Our objective was to measure the association between emergency department (ED) opioid analgesic exposure after a physical, trauma-related event and subsequent opioid use. We hypothesized ED opioid analgesic exposure is associated with subsequent at-risk opioid use.
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