Articles: hyperalgesia.
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With the exception of interdigital neuromas, cutaneous neuromas are relatively rare and often present a diagnostic challenge. ⋯ The diagnosis of cutaneous neuroma should be considered in all patients who have intractable pain and allodynia at unusual locations and in atypical patterns. In addition, ultrasonography can prove very useful in the detection of small cutaneous neuromas if the site of symptoms can be precisely localized.
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To evaluate if sensory, motor, and psychological factors are different in severe lateral epicondylalgia compared with less severe cases and control. ⋯ Lateral epicondylalgia patients presenting with severe pain and disability could be distinguished by hypersensitivity to thermal stimuli, notably bilateral cold hyperalgesia. Findings may implicate a combination of central, peripheral, and sympathetic nervous system processes and may help explain the poorer outcomes found in this subpopulation.
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Randomized Controlled Trial Multicenter Study
Viscerosomatic facilitation in a subset of IBS patients, an effect mediated by N-methyl-D-aspartate receptors.
Irritable bowel syndrome (IBS) is a common gastrointestinal disorder in which the pathophysiological mechanisms of the pain and hypersensitivity are incompletely understood. IBS patients frequently complain of pain in body regions somatotopically distinct from the gut, suggesting involvement of central hyperalgesic mechanisms. We tested the role of tonic peripheral impulse input by using both repetitive thermal stimuli to the leg and repetitive stimuli to the rectum. Changes in thermal/visceral pain sensitivity after nociceptive thermal/visceral repetitive stimulation were determined. A subset of IBS patients showed enhanced rectal/thermal pain sensitivity after repetitive thermal/rectal stimulation, respectively. IBS patients then received 60 mg dextromethorphan and placebo (diphenhydramine) in a randomized, double-blind, crossover trial. The results showed that 1) a subset of IBS patients had increased visceral/cutaneous hypersensitivity following a series of repetitive nociceptive stimuli and that 2) this increased pain sensitivity was blocked by administration of dextromethorphan. This is the first human study indicating that repetitive stimulation enhances a bidirectional mechanism of secondary hyperalgesia due to viscerosomatic facilitation in IBS patients. These unique findings elucidate mechanisms of somatic hypersensitivity in IBS patients and support an etiologic basis for abnormal N-methyl-D-aspartate receptor mechanisms that may be the target of future therapies for IBS. ⋯ Repetitive stimulation enhances a bidirectional mechanism of secondary hyperalgesia due to viscerosomatic convergence in IBS patients. The findings elucidate unique mechanisms of somatic/visceral hypersensitivity in a subset of IBS patients and further support an etiologic basis for abnormal N-methyl-D-aspartate receptor mechanisms that may be future targets of therapies for IBS.
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Randomized Controlled Trial
Low-dose sublingual ketamine does not modulate experimentally induced mechanical hyperalgesia in healthy subjects.
Musculoskeletal pain has been associated with N-methyl-d-aspartate (NMDA) receptor-mediated mechanisms. This randomized controlled trial (RCT) investigated the effect of the NMDA receptor antagonist ketamine (25 mg sublingually) on modulating experimental muscle pain. ⋯ In comparison with placebo, a single low-dose sublingual pharmacological intervention targeting the processes of sensitization via antagonism of NMDA receptors did not modulate the effects of acute experimentally induced mechanical hyperalgesia, suggesting a higher dose or repeat doses may be required.