Pain
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Factors influencing natural history and clinical course of pain in temporomandibular disorders (TMD) are largely unknown. Physical, psychological and behavioral data from a population-based epidemiologic study of TMD were examined in 234 cases of persons reporting TMD pain. The cases were assigned to one of five pain pattern groups based on changes in average TMD pain from baseline to 5-year follow-up: (i) remitted (49% of the sample), (ii) high-improvement (14%), (iii) low-improvement (9%), (iv) same (13%), and (v) worse (16%). ⋯ The three psychological variables, anxiety, depression, and somatization, displayed similar change patterns, but these patterns were distinctly different from those of the physical variables in that the remitted pain group was at the population mean at baseline for these psychological variables and remained there; significant improvement in psychological status was observed only in the pain group showing high improvement. The other three pain change groups exhibited elevated psychological distress scores at both baseline and 5 years. These results indicate that although the relationships among the course of pain, of physical variables, and of psychological variables are complicated, the 5-year outcome in pain is largely independent of readily discernible changes in clinical signs.
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Psychophysical methods were used to investigate pain in human subjects elicited by controlled freezing of the skin using a novel vortex thermode. When cooling stimuli delivered with a small thermode (7 mm diameter) exceeded the normal cold pain threshold into the sub-zero temperature range (-5 to -11 degrees C), all subjects reported an intense, sharp stinging pain sensation which occurred suddenly and was readily differentiated from normal cold pain. The onset of this stinging 'freezing' pain was closely correlated with a sudden increase in skin temperature beneath the thermode of 4.77+/-0.86 degrees C (+/-SD) associated with the phase transition of supercooled water to ice. ⋯ The changes in thermal sensitivity were not accompanied by consistent changes in mechanical sensitivity. These results indicate that a characteristic sharp, stinging pain is reliably evoked abruptly at the phase transition of supercooled skin water to ice The ensuing brief decrease in cold pain threshold with burning quality, coupled with decreased sensitivity to cold, are speculated to reflect a central disinhibition of C-fiber nociceptor input due to reduced cold fiber activity. These effects may be relevant to frostbite, and distinguish themselves from the more pronounced thermal and mechanical hyperalgesia seen following intense freeze lesion of the skin.
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Gabapentin is an effective option for the treatment of neuropathic pain syndromes because of its efficacy and favorable side-effect profile. A case is presented of a 58 year old man who developed a painful polyneuropathy while being treated with gabapentin.