Pain: an overview

Brief presurgery hypnosis reduces distress and pain in excisional breast biopsy patients

Each year, hundreds of thousands of women undergo excisional breast biopsies for definitive diagnosis. Not only do these patients experience pain associated with the procedure, but they also endure distress associated with the threat of cancer. Hypnosis has been demonstrated as effective for controlling patients' pain in other surgical settings, but breast surgery patients have received little attention. To determine the impact of brief presurgical hypnosis on these patients' postsurgery pain and distress and to explore possible mediating mechanisms of these effects, 20 excisional breast biopsy patients were randomly assigned to a hypnosis or control group (standard care). Hypnosis reduced postsurgery pain and distress. Initial evidence suggested that the effects of hypnosis were mediated by presurgery expectations.

Sensory-motor control of the lower back: implications for rehabilitation

Although low back pain (LBP) is a widespread and disabling health problem, there is a lack of evidence based medicine with respect to its treatment and rehabilitation. A major reason for this is the poor understanding of the underlying mechanisms of the LBP syndromes. In an attempt to fill this gap, the present review article provides an overview of the sensory-motor control aspects of trunk stabilization and postural control of the trunk, and how they may relate to the evolution of LBP. In particular, the anatomy and physiology of the sensory-motor control mechanisms of the trunk muscles that contribute to general and segmental stability of the lumbar spine will be elucidated. Furthermore, a brief overview of current theories of postural control will be provided with respect to spinal stabilization. Finally, a concept of the pathophysiological changes within the sensory-motor control mechanisms of the lumbar spine in the presence of muscle injury and pain will be presented. The impact of pain and muscle injury on the muscular support for the lumbar motion segment will be discussed along with the deficits in neuromuscular control in LBP patients with decreased segmental lumbar stability.

Decreased perfusion of the bilateral thalami in patients with chronic pain detected by Tc-99m-ECD SPECT with statistical parametric mapping

The purpose of this study was to examine whether the Tc-99m-ECD SPECT can detect any difference between the brain perfusion in patients with chronic pain and normal controls by means of the Statistical Parametric Mapping (SPM96). The subjects were twelve patients with chronic pain (CP group) and twelve normal controls (NC group). After informed consent was obtained, 720 MBq of Tc-99m-ECD was intravenously injected as a bolus. The SPECT data were acquired once for 20 mins from 5 mins after i.v. injection of Tc-99m-ECD, with a triple-head rotating gamma camera. The SPECT data were transformed into a standard stereotactic space, and group comparisons between CP and NC groups were performed on a voxel-by-voxel basis. The subset of voxels exceeding a threshold of p < 0.001 in omnibus comparisons and remaining significant after correction for multiple comparison (p < 0.05) was displayed as a volume image rendered in three orthogonal projections. There was a significant decrease in perfusion in the bilateral thalami in the CP group, suggesting that perfusion in the thalamus generally decreases in patients with chronic pain. Tc-99m-ECD SPECT with SPM96 may be useful for studies of the mechanisms of chronic pain.

Pain complaints in patients with fibromyalgia versus chronic fatigue syndrome

Individuals with fibromyalgia (FM) and/or chronic fatigue syndrome (CFS) report arthralgias and myalgias. However, only persons with FM alone exhibit abnormal pain responses to mild levels of stimulation, or allodynia. We identify the abnormalities in the neuroendocrine axes that are common to FM and CFS as well as the abnormalities in central neuropeptide levels and functional brain activity that differentiate these disorders. These two sets of factors, respectively, may account for the similarities and differences in the pain experiences of persons with FM and CFS.

Pain in the nursing home

The treatment of pain in the nursing home setting continues to present several unique and challenging problems. Increasingly, studies are focusing on the large number of elderly with important pain problems in long-term care. The inclusion of pain as an area of clinical focus in the Minimum Data Set has fueled interest in this problem and will provide solid data for future study. Researchers are attempting to establish reliable and valid data using standardized assessment tools previously validated in younger adults and are attempting use of traditional and cutting-edge assessment tools in cognitively impaired patients. Assessment is being linked to innovative interventions in noncommunicative, cognitively impaired residents using primary care nurses who best know these patients to decipher "normal" from "abnormal" behavior. The application of available pharmacologic interventions are more challenging because of the higher incidence of side effects in the elderly; part of this problem is the result of the decreased hepatic metabolism and renal clearance present in older patients. The nursing home environment has limited resources that can create logistical concerns in terms of diagnosis and treatment but also can positively limit overly invasive modalities. This article explores these issues and offers suggestions for the appropriate assessment and management of pain in long-term care residents.

Biopsychosocial mediators and moderators of stress-health relationships in patients with recently diagnosed rheumatoid arthritis

OBJECTIVE

To investigate the mediating and moderating roles of social support, coping, and physiological variables in the relationship between life events and health status.

METHODS

Psychological and biological measurements were taken in 54 patients (38 women, 16 men, mean age +/- SD 56 +/-14.4 years) with recently diagnosed rheumatoid arthritis (RA).

RESULTS

Life events were correlated with psychological distress, but not with disease activity. No mediators for the relationship of life events with psychological well-being and disease activity were observed. In 40 tests, 4 moderators were found: Problem-focused coping, perceived support, diastolic blood pressure, and total number of lymphocytes were moderators of the relationship between daily hassles and health status (P < or = 0.05).

CONCLUSION

Our study provides limited support for the notion that the interactions of life stress with biopsychosocial variables have an impact on health. None of these variables were found to be crucial mediators of stress-health associations in recently diagnosed patients with RA, but some provocative evidence was given that biopsychosocial variables may have a minor impact on stress-health relationships.

Psychosocial and health status variables independently predict health care seeking in fibromyalgia

OBJECTIVE

To determine whether variables derived from the self-regulatory model of health and illness behavior accurately predict status as a patient or nonpatient with fibromyalgia (FM).

METHODS

Subjects were 79 patients who met American College of Rheumatology (ACR) criteria for FM and 39 community residents who met ACR criteria for FM but had not sought medical care for their symptoms (nonpatients). Subjects were administered 14 measures that produced 6 domains of variables: background demographics and pain duration; psychiatric morbidity; and personality, environmental, cognitive, and health status factors. These domains were entered in 4 different hierarchical logistic regression analyses to predict status as patient or nonpatient.

RESULTS

The full regression model was statistically significant (P < 0.0001) and correctly identified 90.7% of the subjects with a sensitivity of 92.4% and a specificity of 87.2%. The best individual predictors of group status were self-reports of self-efficacy, negative affect, recent stressful events, and perceived pain. Relative to nonpatients, patients reported higher levels of negative affect and perceived pain and a greater number of recent stressful experiences, as well as lower levels of self-efficacy.

CONCLUSION

Consistent with the self-regulatory model of health and illness behavior, psychosocial and health status variables predict health care-seeking behavior in persons with FM independently of background demographics and psychiatric morbidity. These variables may influence the severity of symptoms experienced by persons with this disorder as well as their health care-seeking behavior, but they are not necessary to produce abnormal pain sensitivity in FM.

Pharmacologic treatment of fibromyalgia

Fibromyalgia is a chronic syndrome characterized by widespread pain, unrefreshed sleep, disturbed mood, and fatigue. Until such time as we have a clearer understanding of the trigger and/or pathophysiologic mechanisms producing these symptoms, pharmacologic treatment should be aimed at individual symptoms. Such treatment should ideally be offered as part of a multidisciplinary treatment program using both pharmacologic and nonpharmacologic treatment modalities. Critical components of any successful fibromyalgia treatment program include addressing physical fitness, work and other functional activities, and mental health, in addition to symptom-specific therapies. The main symptoms that should be addressed include pain, sleep disturbances including restless leg syndrome, mood disturbances, and fatigue. Pharmacologic therapy should also be considered for syndromes commonly associated with fibromyalgia including irritable bowel syndrome, interstitial cystitis, migraine headaches, temporomandibular joint dysfunction, dysequilibrium including neurally mediated hypotension, sicca syndrome, and growth hormone deficiency. This article provides general guidelines in initiating a successful pharmacologic treatment program for fibromyalgia.

The utility of a burn specific measure of pain anxiety to prospectively predict pain and function: a comparative analysis

Patients treated for burn injuries commonly experience high levels of acute pain and anxiety during hospitalization, particularly as it relates to their dressing changes and other medical procedures. A new instrument, the burn specific pain anxiety scale (BSPAS), was designed to characterize patient's anxiety in this setting, but its predictive validity in relation to other measures of anxiety has yet to be demonstrated. In this study, 27 patients with acute burn injuries completed three measures of anxiety upon admission to a major medical burn trauma center. Scores on the anxiety measures were compared with regard to their ability to predict subsequent ratings of procedural and background pain levels, pain medication usage, and physical and emotional functioning upon discharge. In support of criterion-related validity, the BSPAS was the best predictor of procedural pain levels as rated later the same day relative to the other global anxiety measures; moreover, the BSPAS did not predict later-day background pain levels as hypothesized. Both the BSPAS and the global anxiety measures were found to significantly predict total number of pain medications over a 24-h period. Finally, the BSPAS was the only significant predictor of decreased physical role functioning at discharge whereas the other more global measures of anxiety were better predictors of emotional functioning. These results provide preliminary evidence that the BSPAS is a unique and valid indicator of pain-related anxiety surrounding burn care in hospitalized patients and may be useful in identifying those patients at risk for decreased functional capacity at the time of discharge.

Evidence for the use of gabapentin in the treatment of diabetic peripheral neuropathy

BACKGROUND

One of the most common peripheral nerve complications of diabetes is painful diabetic peripheral neuropathy (DPN). Although tricyclic antidepressants (TCAs) have traditionally been used to relieve the pain of this condition, gabapentin's reported efficacy in various neuropathic pain states and its favorable side-effect profile compared with other available agents have led to interest in the use of this agent for the treatment of DPN.

OBJECTIVES

This paper reviews the current clinical literature on the effectiveness and tolerability of gabapentin in the treatment of DPN. It also considers whether the evidence favors gabapentin's use as an alternative or first-line agent.

METHODS

A search of the English- and French-language literature for the years 1990 through 2000 was performed using MEDLINE, Current Contents/Clinical Medicine, and International Pharmaceutical Abstracts, plus the reference lists of the articles identified through this search. The search terms used were gabapentin, anticonvulsant, diabetic peripheral neuropathy, and neuropathy. Included studies were limited to trials in human subjects.

RESULTS

The literature search identified several case reports and case series, as well as 3 small placebo-controlled studies (2 complete, 1 brief report) and 1 comparative trial against the TCA amitriptyline. The designs and dosing regimens differed between studies.

CONCLUSIONS

Many clinicians consider gabapentin an alternative treatment option in patients with DPN who are unable to tolerate traditional agents or in whom traditional agents are contraindicated. To date, gabapentin has been well tolerated, superior to placebo, and equivalent to amitriptyline in small clinical trials of short duration. Although overall efficacy and safety profiles appear to be favorable, larger long-term studies are needed to determine the place of gabapentin in relation to other treatment options. There is currently insufficient evidence from controlled trials to support the use of gabapentin as first-line therapy for DPN.

Preoperative anxiety and postoperative pain in women undergoing hysterectomy. A repeated-measures design

OBJECTIVES

To determine whether psychological variables such as preoperative anxiety can serve as predictors for the postoperative pain response.

METHODS

The study sample included women who underwent elective abdominal hysterectomy (n=53). Two weeks prior to surgery, characteristics such as trait anxiety, coping style, and perceived stress were evaluated. Throughout the perioperative period, state anxiety, pain, as well as analgesic consumption were assessed at multiple time points. The anesthetic and surgical management were carefully controlled for and postoperative pain management was standardized.

RESULTS

Path analysis demonstrated that there are both direct and indirect effects of preoperative state anxiety on postoperative pain. Preoperative state anxiety is a significant positive predictor of the immediate postoperative pain (beta=0.30), which, in turn, is a positive predictor of pain on the wards (beta=0.54). Pain on the ward, in turn, is predictive for pain at home (beta=0.30).

CONCLUSION

The results of this study indicate that preoperative anxiety may have a critical role in the chain-of-events that controls the postoperative pain response.

Naturally occurring antinociceptive substances from plants

Despite the progress that has occurred in recent years in the development of therapy, there is still a need for effective and potent analgesics, especially for the treatment of chronic pain. One of the most important analgesic drugs employed in clinical practice today continues to be the alkaloid morphine. In this review, emphasis will be given to the important contribution and the history of Papaver somniferum, Salix species, Capsicum species and Cannabis sativa in the development of new analgesics and their importance in the understanding of the complex pathways related to electrophysiological and molecular mechanisms associated with pain transmission. Recently discovered antinociceptive substances include alkaloids, terpenoids and flavonoid. Plant-derived substances have, and will certainly continue to have, a relevant place in the process of drug discovery, particularly in the development of new analgesic drugs.

NK1 (substance P) receptor antagonists--why are they not analgesic in humans?

Tachykinin NK1 receptor antagonists have failed to exhibit efficacy in clinical trials of a variety of clinical pain states. By contrast, in preclinical studies in animals NK1 receptor antagonists have been shown to attenuate nociceptive responses sensitized by inflammation or nerve damage, although they exhibit little effect on baseline nociception. Other agents with this profile of activity in animal tests, typically nonsteroidal anti-inflammatory drugs (NSAIDs), are analgesic in humans. Thus, NK1 receptor antagonists appear able to block behavioural responses to noxious and other stressful sensory stimuli at a level detectable in animal tests but fail to provide the level of sensory blockade required to produce clinical analgesia in humans.

Pain: neuroanatomy, chemical mediators, and clinical implications

Most pain information begins at simple, naked nerve endings called nociceptors that form a functional pain unit with nearby tissue capillaries and mast cells. Tissue injury causes these nerve terminals to depolarize, an event that is propagated along the entire afferent fiber eventuating in sensory impulses reaching the spinal cord. This firing of primary afferent fibers at the site of tissue injury causes axonal release of vesicles containing neuropeptides such as substance P, which acts in an autocrine and paracrine manner to sensitize the nociceptor and increase its rate of firing. Cellular damage and inflammation increase concentrations of other chemical mediators such as histamine, bradykinin, and prostaglandins in the area surrounding functional pain units. These additional mediators act synergistically to augment the transmission of nociceptive impulses along sensory afferent fibers. Primary fibers travel from the periphery to the dorsal horn where they synapse on secondary neurons and interneurons. When activated, interneurons exert inhibitory influences on further pain signal trafficking. Efferent supraspinal influences, in turn, determine the activity of interneurons by releasing a variety of neurotransmitter substances, thus resulting in a high degree of modulation of nociception within the dorsal horn. Events occurring in the periphery and in the dorsal horn can cause a dissociation of pain perception from the presence or degree of actual tissue injury. These phenomena involve many chemical mediators and receptor systems, and can increase pain experience qualitatively, quantitatively, temporally, and spatially. The complexity and plasticity of the nociceptive system can make clinical management of pain difficult. Undestanding the structure and chemical signals associated with this system can improve the use of existing analgesics and provide targets for development of newer and more specific pain-fighting drugs.

Uses of guided imagery for pain control by african-american and white women with metastatic breast cancer

Understanding the meanings patients attach to their experiences can help clinicians and researchers to more adequately address a patient's experience with cancer pain. Indeed, many patients seem to desire to and benefit from attaching meaning to the disease and its treatment. In particular, many patients are drawn to guided imagery as a tool in the management of cancer-related anxiety and pain. Using excerpts from African-American and White women's breast cancer narratives, we show that breast cancer survivors use guided imagery as a vehicle for reconnecting to the self, to make sense of their experiences with breast cancer, and as a tool for managing cancer pain. Cancer pain increases the disruption in the connection between the body and the mind that is already part of the illness experience. Guided imagery can be regarded as one response to this problem, and may be understood as an attempt to reconnect mind and body in a manner that increases the sense of control, thereby alleviating the suffering of the survivor.

Taste and smell phantoms revealed by brain functional MRI (fMRI)

PURPOSE

Our goal was to demonstrate the appearance of phantom tastes and smells (phantageusia and phantosmia, respectively) by use of functional MRI (fMRI) of the brain and to demonstrate the efficacy of drug treatment that inhibited both the subjective presence of these phantoms and the fMRI brain activation initiated by these phantoms.

METHOD

Multislice FLASH MR or echo planar MR brain scans were obtained in two patients with phantageusia and phantosmia in response to memory of two tastants (salt and sweet); memory of two odors (banana and peppermint); actual smell of amyl acetate, menthone, and pyridine; and memory of phantom tastes and smells before and after treatment with thioridazine and haloperidol. Activation images were derived using correlation analysis, and ratios of brain area activated to total brain area were obtained.

RESULTS

Prior to treatment, both patients experienced persistent birhinal and global oral obnoxious tastes and smells in the absence of any external stimulus. The fMRI response to memory of phantoms was activation in sensory-specific brain regions for taste and smell, respectively. fMRI activation was greater than for memory of any tastant or odorant or for actual smell of any odor. After treatment with thioridazine or haloperidol, which successfully inhibited each phantom in each patient, fMRI response to phantom memory was significantly inhibited and was significantly lower than for memory of any tastant or odorant or actual smell of any odorant.

CONCLUSION

These results demonstrate that (a) phantom taste and smell can be revealed by fMRI brain activation, (b) brain activation in response to taste and smell phantoms is localized in sensory-specific brain regions for taste and smell, respectively, (c) brain activation in response to memory of each phantom initiated the greatest degree of activation we had previously measured, and (d) treatment with thioridazine or haloperidol inhibited both the presence of each phantom and its associated fMRI brain activation. This is the first study in which phantom tastes and smells have been demonstrated by an objective technique and treatment that inhibited the phantoms was characterized by objective inhibition of fMRI activation. These two patients represent a relatively common group that may be classified as having primary phantageusia and phantosmia distinct from those with phantoms or auras secondary to neurological, migrainous, psychiatric, or other causes.