The journal of pain : official journal of the American Pain Society
-
A number of experimental studies in animals have suggested that voltage-gated sodium channels may play a crucial role in neuropathic pain. However, it is still difficult to translate the pathophysiological mechanisms identified in animal studies to the clinic and several questions regarding the role of sodium channels in neuropathic pain must therefore be addressed primarily in the clinical setting. Despite providing indirect information, pharmacologic challenge using sodium channel blockers, such as some antiepileptics, local anesthetics and derivatives, is the best way to investigate the role of sodium channels in the various clinical symptoms of neuropathies (eg, spontaneous pain, mechanical or thermal allodynia, and hyperalgesia). Randomized controlled trials have demonstrated the efficacy of these compounds for various neuropathic pain conditions. Recent psychophysical studies in which symptoms and signs are more accurately assessed indicate that these compounds act as antihyperalgesic agents rather than as simple analgesics. They also show that the sensitivity to these drugs is not affected by the aetiology of pain and the peripheral or central location of the nerve lesion. These data emphasize the role of peripheral and central sodium channels in neuropathic pain. Studies using more selective sodium channel blockers are required to gain further insight into the role of the various subtypes of sodium channel in these pain conditions. ⋯ Pharmacological challenge using sodium channel blockers is the best way to translate basic research on sodium channels in human neuropathic pain. To date, the role of sodium channels in neuropathic pain symptoms/signs is mostly documented for mechanical static and dynamic allodynia, and either peripheral or central sodium channels may be involved.
-
Review Guideline
Guidelines for the cold pressor task as an experimental pain stimulus for use with children.
The cold pressor task (CPT) involves placing a hand or forearm in cold water, a stimulus that produces a slowly mounting pain of mild to moderate intensity and is terminated by voluntary withdrawal of the limb. The CPT has been used in many studies of pain, autonomic reactivity, and hormonal stress responses. Use of the CPT with children was first reported in 1937, and it has been used since then in at least 24 published studies including more than 1700 children without reported adverse effects. However, differences in water temperature, apparatus, and procedure might contribute to conflicting results. We offer suggested guidelines for the safe construction and operation of apparatus for the CPT and for consistent administration of the task and measurement. In particular, use of continuously circulating water at a temperature of 10 degrees C +/- 1 degrees C is recommended for the CPT with children and adolescents. Data on children's pain tolerance found in CPT studies in the authors' laboratories are provided. ⋯ Differences in methodology might have contributed to conflicting results in published research using the CPT with children. These guidelines for apparatus and for administration of the CPT might be helpful to researchers planning such studies. Questions for research leading toward further methodologic refinement are identified.
-
Review Case Reports
Ethical challenges in the management of chronic nonmalignant pain: negotiating through the cloud of doubt.
After successful cancer pain initiatives, efforts have been recently made to liberalize the use of opioids for the treatment of chronic nonmalignant pain. However, the goals for this treatment and its place among other available treatments are still unclear. Cancer pain treatment is aimed at patient comfort and is validated by objective disease severity. For chronic nonmalignant pain, however, comfort alone is not an adequate treatment goal, and pain is not usually proportional to objective disease severity. Therefore, confusion about treatment goals and doubts about the reality of nonmalignant pain entangle therapeutic efforts. We present a case history to demonstrate that this lack of proportionality fosters fears about malingering, exaggeration, and psychogenic pain among providers. Doubt concerning the reality of patients' unrelieved chronic nonmalignant pain has allowed concerns about addiction to dominate discussions of treatment. We propose alternate patient-centered principles to guide efforts to relieve chronic nonmalignant pain, including accept all patient pain reports as valid but negotiate treatment goals early in care, avoid harming patients, and incorporate chronic opioids as one part of the treatment plan if they improve the patient's overall health-related quality of life. Although an outright ban on opioid use in chronic nonmalignant pain is no longer ethically acceptable, ensuring that opioids provide overall benefit to patients requires significant time and skill. Patients with chronic nonmalignant pain should be assessed and treated for concurrent psychiatric disorders, but those with disorders are entitled to equivalent efforts at pain relief. The essential question is not whether chronic nonmalignant pain is real or proportional to objective disease severity, but how it should be managed so that the patient's overall quality of life is optimized. ⋯ The management of chronic nonmalignant pain is moving from specialty settings into primary care. Primary care providers need an ethical framework within which to adopt the principles of palliative care to this population.
-
Children's memories of painful experiences can have long-term consequences for their reaction to later painful events and their acceptance of later health care interventions. This review surveys research on children's memory for pain, emphasizing implications for clinical practice. Topics reviewed include consequences of children's memories of pain; the development of memory; differences between explicit (declarative, verbal, autobiographic) memory and implicit (nondeclarative, nonverbal) memory; and individual differences, situational, and methodologic factors affecting memories of pain. Methods to prevent the adverse consequences of remembered pain are addressed with reference to current research on editing or reframing memories. ⋯ This review covers topics of value to clinicians providing care to children undergoing painful procedures. Specific recommendations are offered regarding the importance of acknowledging and assessing children's previous memories of painful experiences, the type of information that benefits children before and after procedures, and the most appropriate questioning strategies. It might be possible to prevent or reduce the adverse effects of memories of pain.
-
Adaptive management of chronic pain depends to a large degree on how patients choose to cope with pain and its impact. Consequently, patient motivation is an important factor in determining how well patients learn to manage pain. However, the role of patient motivation in altering coping behavior and maintaining those changes is seldom discussed, and theoretically based research on motivation for pain treatment is lacking. ⋯ The implications of this model for enhancing engagement in and adherence to chronic pain treatment programs are then discussed. The article ends with a call for research to better understand motivation as it applies to chronic pain self-management. In particular, there is a need to determine whether (and which) motivation enhancement interventions increase active participation in self-management treatment programs for chronic pain.