Pain
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The results of a considerable number of recent prospective studies have demonstrated that greater acute pain severity in herpes zoster patients is associated with a significantly greater risk of developing postherpetic neuralgia (PHN). Only a few studies have examined the relationships between acute pain severity and demographic characteristics and clinical features of patients with herpes zoster, however, and the results of these studies have been inconsistent. ⋯ These results demonstrate that three of the established risk factors for PHN - older age, greater rash severity, and the presence of a prodrome - are also associated with more severe acute pain assessed soon after rash onset in patients with herpes zoster. The results of this study are consistent with the recommendation that herpes zoster patients who are older, who have had a prodrome, or who have severe rash or severe acute pain should be targeted for interventions designed to prevent PHN.
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Randomized Controlled Trial Clinical Trial
The role of fear-avoidance beliefs in acute low back pain: relationships with current and future disability and work status.
Fear-avoidance beliefs have been identified as an important psychosocial variable in patients with chronic disability doe to low back pain. The importance of fear-avoidance beliefs for individuals with acute low back pain has not been explored. Seventy-eight subjects with work-related low back pain of less than 3 weeks'duration were studied. ⋯ Fear-avoidance beliefs about work were significant predictors of 4-week disability and work status even after controlling for initial levels of pain intensity, physical impairment, and disability, and the type of therapy received. Fear-avoidance beliefs are present in patients with acute low back pain, and may be an important factor in explaining the transition from acute to chronic conditions. Screening for fear-avoidance beliefs may be useful for identifying patients at risk of prolonged disability and work absence.
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Coincident with nociception, both noxious chemical stimulation of the hind paw and chronic constriction injury (CCI) of the sciatic nerve produce an increase in protein kinase C (PKC) translocation in the spinal cord of rats. Noxious stimulus-induced PKC translocation likely depends on glutamate activity at either N-methyl-D-aspartate (NMDA) receptors or group I metabotropic glutamate receptors (mGluR1/5) in the spinal cord dorsal horn. This study compares nociceptive responses to, and the alterations in membrane-associated PKC, induced by noxious chemical stimulation of the hindpaw and CCI of the sciatic nerve, as well as their modulation by both NMDA and mGluR1/5 receptor antagonists. ⋯ In contrast, i.t. treatment with (S)-4CPG failed to significantly affect either nociceptive behaviours in the formalin test or formalin-induced increases in [3H]-PDBu binding in laminae I-II and III-VI of the lumbar spinal cord. On the other hand, i.t. treatment with either MK-801 or (S)-4CPG produced a significant reduction in mechanical and cold hypersensitivity, as well as [3H]-PDBu binding in laminae I-II and III-VI of the lumbar spinal cord, after CCI. These results suggest that while NMDA, but not mGluR1/5, receptors are involved in translocation of PKC and nociception in a model of persistent acute pain, both types of receptors influence the translocation of PKC in dorsal horn and mechanical and cold allodynia in a model of chronic neuropathic pain.
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Protein kinase A (PKA) can play a critical role in the modulation of neuronal excitability. We examined the role of PKA in the modulation of abnormal spontaneous activity (SA) originating from the chronically compressed dorsal root ganglion (CCD). The L(4) and L(5) dorsal root ganglia (DRGs) were compressed by inserting a stainless steel rod into each corresponding intervertebral foramen. ⋯ Sp-cAMPS (500 microM), a specific activator of PKA, increased the discharge rate of SA in all injured units tested, but did not trigger firing in silent neurons. Okadaic acid (0.1 microM), a protein phosphatase inhibitor, and forskolin (1 microM), an adenyl cyclase activator, each significantly increased the discharge rate of SA. These results strongly suggest that PKA modulates the SA in injured DRG neurons with myelinated axons.
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Inadequate relief from cancer pain is an international health problem. The aim of this study was to document the prevalence and patterns of cancer pain management in the Republic of South Africa. The first phase of this study consisted of screening 263 patients to document the prevalence of cancer pain in varying settings. ⋯ Of this group, 58.1% were experiencing severe 'worst pain'. Unrelieved cancer pain is a significant problem. Government and non-government leaders, educators, and practitioners must collaborate to address the barriers to effective pain management and to implement improvements in education, health policy, and health care delivery.