Articles: hyperalgesia.
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Curr Pain Headache Rep · Apr 2011
ReviewOpioid-induced hyperalgesia: clinically relevant or extraneous research phenomenon?
Opioids have become the unequivocal therapy of choice in treating many varieties of chronic pain. With the increased prescription of opioids, some unintended consequences have occurred. After prolonged opioid exposure, opioid-induced hyperalgesia (OIH), the paradoxical effect that opioid therapy may in fact enhance or aggravate preexisting pain, may occur. ⋯ However, not all evidence supports the clinical importance of OIH, and some question whether the phenomenon exists at all. Here, we present a nonexhaustive, brief review of the recent literature. OIH will be reviewed in terms of preclinical and clinical evidence for and against its existence; recommendations for clinical evaluation and intervention also will be discussed.
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J. Gastroenterol. Hepatol. · Apr 2011
Randomized Controlled Trial Comparative StudyVisceral sensation and irritable bowel syndrome; with special reference to comparison with functional abdominal pain syndrome.
Stress-induced visceral hypersensitivity may play an important role in the pathogenesis of irritable bowel syndrome (IBS) but not in functional abdominal pain syndrome (FAPS). We examined rectal sensation in those patients. ⋯ RRD-induced rectal hypersensitivity seems to be reliable marker for IBS, and CRF may contribute to this response. FAPS patients may have hyposensitivity to non-noxious physiological distention, suggesting FAPS has different pathogenesis from IBS.
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Oxaliplatin is a key drug for colorectal cancer, but it causes acute peripheral neuropathy (triggered by cold) and chronic neuropathy (sensory and motor neuropathy) in patients. Neurotropin, a non-protein extract from the inflamed rabbit skin inoculated with vaccinia virus, has been used to treat various chronic pains. In the present study, we investigated the effect of neurotropin on the oxaliplatin-induced neuropathy in rats. ⋯ Neurotropin also inhibited the oxaliplatin-induced neurite degeneration in cultured pheochromocytoma 12 (PC12) and rat dorsal root ganglion (DRG) cells. On the other hand, neurotropin did not affect the oxaliplatin-induced cell injury in rat DRG cells. These results suggest that repeated administration of neurotropin relieves the oxaliplatin-induced mechanical allodynia by inhibiting the axonal degeneration and it is useful for the treatment of oxaliplatin-induced neuropathy clinically.
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Recently we demonstrated brush-evoked allodynia to be a partially graded phenomenon since increased brushing length and number of strokes significantly increased the brush-evoked pain intensity. In this study the influence of stroking velocity and brushing force on dynamic mechanical allodynia was examined in 16 patients with peripheral neuropathy. Brush-evoked allodynia was induced by lightly stroking 60mm of the skin twice with a 16 mm wide brush while varying stroking velocity (10, 20, 30 mm/s) and brushing force (10, 20, 40 g). ⋯ Higher maximum pain intensity was reported with higher brushing force. In conclusion, our findings demonstrated a significant relationship between the total brush-evoked pain intensity and stroking velocity as well as brushing force. Together with previously accumulated data these results substantiate the usefulness of this semi-quantitative assessment method in longitudinal studies on dynamic mechanical allodynia.
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Idiopathic or functional abdominal pain (FAP) is common in school-age children and typically reflects a functional gastrointestinal disorder (FGID). FGIDs in adults have been distinguished by enhanced responses of the central nervous system to pain stimuli, known as central sensitization. This study investigated whether adolescents and young adults with a history of pediatric FAP (n=144), compared with well control subjects (n=78), showed enhanced central sensitization demonstrated by greater temporal summation (wind-up) to brief, repetitive heat pulses. ⋯ Although anxiety was significantly higher in the FAP group compared with control subjects (P<.01) and in women compared with men (P<.05), anxiety did not explain the increased wind-up observed in women with a childhood history of FAP. Results suggest that women with a pediatric history of FAP may have a long-term vulnerability to pain associated with enhanced central nervous system responses to pain stimuli. Young women with a childhood history of functional abdominal pain may have a long-term vulnerability to pain that is associated with enhanced responses of the central nervous system to pain stimuli.