Contribution of corticosteroid to the treatment of pain in the acute phase of Guillain-Barré syndrome

INTRODUCTION: Pain is a common problem in both adults and children with Guillain-Barré Syndrome (GBS). Corticosteroids are rarely used in the treatment of pain in the course of GBS, although some authors have pointed out their value for the treatment of neuropathic pain. We report four patients with GBS whose pain was rapidly relieved by administration of corticosteroids. METHODS: We reviewed retrospectively a series of four patients with GBS seen from September 2001 to February 2003. All patients had plexual (Case 3), trunkular (case 1), radicular (case 2) or focal (case 4) pain. Pain was treated with corticosteroids via oral (cases 1 and 2) or intravenous routes (cases 3 and 4). Corticoids where used after failure of other analgesic agents. RESULTS: Pain relief was obtained after the first administration and persisted even after tapering off steroid treatment. No particular complication was observed during treatment course. CONCLUSION: Our experience suggests that controlled studies should be set up to evaluate the place of corticosteroid treatment for the management of pain in patients with GBS.     

Financing the treatment of chronic pain: models for risk-sharing among pain medicine physicians, health care payers, and consumers

Chronic pain patients are among a growing group of medically underserved Americans. Despite increasing public awareness about pain and widespread legislative activity that is focusing on the needs of pain patients, there remain significant roadblocks in bringing the expertise of Pain Medicine specialists to these unfortunate people. This paper explores how the managed care revolution has impacted the practice of Pain Medicine in the United States. The dissolution of many prominent multi-disciplinary pain treatment centers has been paralleled by the evolution of pain management as an area of interest by several competing medical specialty societies. Despite this fragmentation, the American Academy of Pain Medicine continues to grow and to promote the needs of Pain Medicine specialists and their patients. The advantages and disadvantages of various practice patterns for Pain Medicine specialists is explored against a backdrop of discussions about: (1) the problems currently faced by chronic pain patients; (2) the role of organized Pain Medicine in helping patients to access and finance care; and (3) the future of American health care and the new responsibilities that will bring to physicians. Finally, we have some specific recommendations for pain medicine specialists about: (1) sharing risk; (2) exerting individual leadership; and (3) simplifying one's professional life in the new health care environment, that we hope will enable them to continue caring for as many chronic pain patients as possible. It is opined that the development of sophisticated regional specialty networks is the best model to accomplish this task in the future.     

Differences in pain perception and sensory discrimination between chronic low back pain patients and healthy controls.

Pain perception threshold (PPT), maximal pain tolerance (MPT) and pain discrimination of CLBP patients and controls were tested. Pain perception threshold was significantly higher in the patient group for two different pain stimuli (electrical and pressure pain). Maximal pain tolerance was significantly higher in CLBP patients only for the pressure pain stimulus. There was no difference between the groups in their capacity to discriminate between painful stimuli of different intensity, as measured by a forced-choice task. It is concluded that CLBP patients have a decreased sensitivity for experimental pain. Two theories which might explain this decreased sensitivity are discussed.     

Pain in Parkinson's disease

Pain and other nonmotor symptoms in PD are increasingly recognized as a major cause of reduced health-related quality of life. Pain in PD may be categorized into a number of different subtypes, including musculoskeletal, dystonic, radicular neuropathic, and central pain. The onset of pain can vary in relation to motor symptoms, and may precede the appearance of motor symptoms by several years, or occur after the diagnosis of PD has been made. Pain in PD is frequently under-recognized and is often inadequately treated. Levodopa-related dystonia may respond to manipulation of dopaminergic medication. Dopaminergic therapy may also improve musculoskeletal pain related to rigidity and akinesia, as well as akathisia in PD. Botulinum toxin injections can be effective for treatment of painful focal dystonia. Pain and dysesthesia have been reported to improve with DBS, in some cases. Increased understanding of basal ganglia pathways has provided further insights into the pathogenesis of pain in PD, but the exact mechanism of pain processing and modulation remains unclear.     

The Mahoney Pain Scale: examining pain and agitation in advanced dementia

Pain and distress are widespread for people with dementia. However, effective pain management is limited by the quality of assessment tools. In this study, the development and trial of the Mahoney Pain Scale, which aims to assess pain in advanced dementia and distinguish it from agitation is described. A total of 112 participants with advanced dementia who experienced either pain, agitation, neither or both were assessed via the Mahoney Pain Scale during a pleasant and aversive activity. The Mahoney Pain Scale demonstrated adequate interrater reliability and internal consistency. As predicted, participants experiencing pain and/or agitation obtained higher Mahoney Pain Scale scores during the aversive activity. Participants also differed with respect to their pattern of scores, and consequently, the Mahoney Pain Scale differentiated pain states from non-pain ones. The clinical impressions of nurses who trialed the tool were favorable; they reported that it seemed accurate and easy to use. Thus, the Mahoney Pain Scale may be useful for assessing pain in dementia.     

The classification and assessment of pain

One of the most challenging and perplexing issues facing researchers and practitioners who study and treat pain are the basic ones of how best to define, evaluate, measure, and classify it. Many instruments for assessing and classifying pain have been propagated. Unfortunately, for many years, the dualistic approach that pain is primarily either owing to physical or psychological factors has influenced how pain is conceptualized as a medical entity. Newer classification systems including that developed by the International Association for the Study of Pain and diagnoses (e.g. Pain Disorder in DSM-IV) recognize the complex nature of pain.     

The role of oxytocin,vasopressin, and their receptors at nociceptors in peripheral pain modulation

Oxytocin and vasopressin are neurohypophyseal hormones with sequence similarity and play a central role in bodily homeostatic regulation. Pain is currently understood to be an important phenotype that those two neurohormones strongly downregulate. Nociceptors, the first component of the ascending neural circuit for pain signals, have constantly been shown to be modulated by those peptides. The nociceptor modulation appears to be critical in pain attenuation, which has led to a gradual increase in scientific interest about their physiological processes and also drawn attention to their translational potentials. This review focused on what are recently understood and stay under investigation in the functional modulation of nociceptors by oxytocin and vasopressin. Effort to produce a nociceptor-specific view could help to construct a more systematic picture of the peripheral pain modulation by oxytocin and vasopressin.     

Endothelin-1 and metastatic cancer pain

Pain in patients with metastatic cancer contributes to increased suffering in those already burdened by their advancing illness. The causes of this pain are unknown but likely to involve the action of tumor-associated mediators and their receptors. One such mediator, endothelin-1 (ET-1), can induce both pain-like behavior in animals and pain in humans that is endothelin-A (ET(A)) receptor-dependent, and that appears to be due to the selective excitation of pain fibers. More significantly, in clinical studies, antagonists of the ET(A) receptor have been shown to ameliorate pain in some patients with advanced metastatic prostate cancer. The identification of tumor-associated mediators such as ET-1 that might directly or indirectly cause pain in patients with metastatic disease should lead to improved, targeted analgesia for patients with advanced cancer.     

Quality of life in major depressive disorder: the role of pain and pain catastrophizing cognition

ObjectivePain symptoms are frequent complaints in patients with major depressive disorder (MDD). Although it is known that pain intensity and pain-related cognition predict quality of life (QOL) in patients with chronic pain, limited studies have examined their roles in MDD. The study aimed to determine whether pain and pain catastrophizing were independent predictors of QOL in MDD after accounting for the impact of anxiety and depression.MethodsThis is a prospective, naturalistic follow-up study. Ninety-one Chinese patients were enrolled during an acute episode of MDD, 82 of them were reassessed 3 months later using the same assessment on pain, anxiety, depression, and QOL. Pain intensity was evaluated using a verbal rating scale and a visual analog scale. Quality of life was assessed using the 36-item Short Form Health Survey. Pain-related cognition was assessed at baseline with the Pain Catastrophizing Scale.ResultsThere was significant improvement in pain, anxiety, depression, and QOL from baseline to 3-month follow-up. Hierarchical regression analyses showed that pain intensity was significantly associated with QOL at baseline and 3 months. Pain complaint was more important than anxiety and depressive symptoms in predicting changes in both physical and psychosocial domains of QOL. After controlling for the severity of pain, anxiety, and depression, Pain Catastrophizing Scale score was independently associated with QOL in MDD.ConclusionThe study supports the specific role of pain and pain-related cognition in predicting QOL in depressed patients. Further studies targeting pain-related cognition for improving the outcome of MDD are necessary.     

Pain emotion and homeostasis

Pain has always been considered as part of a defensive strategy, whose specific role is to signal an immediate, active danger. This definition partially fits acute pain, but certainly not chronic pain, that is maintained also in the absence of an active noxa or danger and that nowadays is considered a disease by itself. Moreover, acute pain is not only an automatic alerting system, but its severity and characteristics can change depending on the surrounding environment. The affective, emotional components of pain have been and are the object of extensive attention and research by psychologists, philosophers, physiologists and also pharmacologists. Pain itself can be considered to share the same genesis as emotions and as a specific emotion in contributing to the maintenance of the homeostasis of each unique subject. Interestingly, this role of pain reaches its maximal development in the human; some even argue that it is specific for the human primate.     

Inclusion Body Myositis

Pain is a common symptom in multiple sclerosis (MS) and has recently been estimated to be experienced by up to 75 % of patients. Pain can be present at any point in the course of the disease and patients may experience pain from various causes simultaneously. Pain in MS can also be secondary to other symptoms, such as spasticity, fatigue, and mood disorder. Of all drug use to treat MS symptoms, treatment for pain accounts for nearly 30 % of total use. At the same time, patients report low satisfaction with pain management. Pain affects quality of life and can influence a person’s participation in family life and work and affect mood. Most of the pain literature in the field of MS is based on open-label studies involving small numbers of subjects. Placebo-controlled trials in severe pain syndromes such as trigeminal neuralgia are unethical but for other types of MS-related pain conditions, placebo-controlled trials are ethical and necessary to establish efficacy, particularly given the well-documented placebo effect for various painful conditions This review discusses available data and emphasizes areas of pain research that require further attention     

Atypical presentations of spinal cord tumors in children.

Pain is a frequent presenting symptom of spinal cord tumors in children and usually manifests as local spinal pain in the bony segments overlying the tumor. Two pediatric patients are presented in whom the diagnosis of intramedullary spinal cord tumors was delayed for many months because their pain was atypical. One had recurrent abdominal pain diagnosed as irritable bowel syndrome. The other had very abrupt paroxysmal but infrequent attacks of arm pain and no neurologic abnormalities. Possible mechanisms of their pain, as well as the other features that might have suggested the diagnosis, are discussed.     

Characterisation of pain in people with hereditary neuropathy with liability to pressure palsy

Hereditary neuropathy with liability to pressure palsy (HNPP) has historically been considered a pain-free condition, though some people with HNPP also complain of pain. This study characterised persistent pain in people with HNPP. Participants provided cross-sectional demographic data, information on the presence of neurological and persistent pain symptoms, and the degree to which these interfered with daily life. The painDETECT and Central Sensitization Inventory questionnaires were used to indicate potential neuropathic, central sensitisation and musculoskeletal (nociceptive) pain mechanisms. Additionally, participants were asked if they thought that pain was related to/part of HNPP. 32/43 (74%) subjects with HNPP had persistent pain and experience this pain in the last week. Of those with pain, 24 (75%) were likely to have neuropathic pain and 27 (84%) were likely to have central sensitisation. All 32 participants felt that their pain could be related to/part of their HNPP. Significant negative impact of the pain was common. Pain characterisation identified neuropathic pain and/or central sensitisation as common, potential underlying processes. Pain may plausibly be directly related to the underlying pathophysiology of HNPP. Further consideration of including pain as a primary symptom of HNPP is warranted.     

Treatment of neuropathic pain in Sierra Leone

During Sierra Leone's violent decade-long war, the warring parties used amputation, especially of arms, as a means of terror. In a camp for amputees in the capital city Freetown, Médecins Sans Frontières established a clinic and a treatment programme for neuropathic pain. Insecurity and cultural and language barriers have complicated this work, but medical and humanitarian benefits have been demonstrated. Pain services are virtually non-existent in less-developed countries. There have recently been no major treatment advances for neuropathic or phantom pain; however, the general body of knowledge about amputation pain can be increased by observations from these difficult settings.     

Pain's impact on adaptive functioning

Background Pain interferes with the functioning of typical children, but no study has examined its effect on children with pre‐existing intellectual disabilities (ID). Methods Caregivers of 63 children observed their children for 2‐h periods and recorded in 1‐week diaries: pain presence, cause, intensity and duration. Caregivers also recorded the children’s performance of pre‐existing skills during each period. Proportion of skills displayed when pain was present and absent was compared. Fifty caregivers completed a second set of observations when pain was present and absent. Results Comparison of the first set of observations indicated children displayed significantly more abilities (64%) when pain‐free (Pain‐Free Day 1), than when pain was present (54%; Pain Day 1). Children displayed 64% of their possible abilities during Pain‐Free Day 2, but only 53% during Pain Day 2. Pain impacted all areas of function (communication, daily living, social and motor skills). Children’s physical and demographic characteristics did not moderate the impact of pain on function, but functioning of children with more severe ID was most impacted by pain. Conclusions Children perform fewer adaptive skills when pain is present. This could affect long‐term functioning as well, through reduced practice of skills.     

Pain, malingering, and performance on the WAIS-III Processing Speed Index

Pain patients often report cognitive symptoms and many will include them in their claims of disability. The Processing Speed Index (PSI) of the WAIS-III was investigated as one aspect of cognitive functioning in six groups. Slight impairment was found for PSI and Digit Symbol subtest performance, but not for Symbol Search, in a Laboratory-induced Pain group and a Clinical Pain group. The lowest scores were found in a Simulator group instructed to fake cognitive impairment and a Clinical Pain group diagnosed as Malingering. Results suggest that PSI scores are only slightly reduced by laboratory-induced pain or chronic pain, and that unexpectedly low scores in the absence of significant/documented brain dysfunction suggest poor effort or deliberate misrepresentation.     

Pain assessment and management in disorders of consciousness

PURPOSE OF REVIEW: Pain and suffering controversies in persons with disorders of consciousness continue to be debated by the scientific, legal and medical ethics communities. This review examines the current knowledge base for guiding decisions regarding assessment and management of pain in persons with disorders of consciousness. RECENT FINDINGS: Studies have shown that brain processing linked to pain in persons in a vegetative state is incomplete and is processed only at a primary and not higher secondary level. Therefore, such painful stimuli would not reach the threshold for conscious experience. In contrast, persons in a minimally conscious state have been shown to have brain activation patterns to pain similar to controls. Therefore, these patients may have sufficient cortical integration and access to afferent information to allow for nociceptive stimuli to be consciously processed. Data to date do not allow for differentiation of the degree of any conscious pain experience or determination of whether individuals with disorders of consciousness are able to suffer. SUMMARY: Pain and suffering should be considered in all persons with disorders of consciousness and adequately treated. Behavioural assessment scales developed for patients unable to speak could be used to assess pain. Future studies should focus on methodologies for specific pain measures relevant to this unique and challenging patient population.     

Analysis of long-standing nociceptive and neuropathic pain in patients with post-polio syndrome

The purpose of this study was to analyze pain, both nociceptive and neuropathic, in patients with post-polio syndrome (PPS) and relate the pain to age at the initial polio infection, age at examination, to gender and disability. The study was conducted in a university hospital department. Patients with PPS were interviewed at their regular visits about pain, its character, intensity and localization. A clinical examination, including a thorough neurological examination, was performed. Data included age at time of polio infection, age at time of examination and gender. Pain intensity was measured with the VAS-scale and walking capability by the WISCI-scale. One hundred sixty-three (88 women, 75 men) patients were included in the study. Pain was present in 109 (67%). Pain was more frequently reported by women (82%) than by men (49%). 96 patients experienced nociceptive pain, 10 patients both neuropathic and nociceptive pain and three experienced pure neuropathic pain. Half of the patients with pain experienced pain in more than one body region. When neuropathic pain was present, another additional neurological disorder was diagnosed. Pain was more often found in younger patients (around 70%) than in older patients (around 50%). In summary pain is common in patients with PPS and most patients experienced nociceptive pain. Women have pain more often than men. Older patients experience pain more seldom than younger patients. Age at time of primary polio infection is important for the development of pain. When neuropathic pain is present, it is important to proceed with neurological examination to find an adequate diagnosis.     

The role of pain modulators in esophageal disorders – no pain no gain

Pain modulators have been primarily used for the management of functional esophageal disorders. Recently, these drugs have also been used for the management of other esophageal disorders, such as non‐erosive reflux disease, the hypersensitive esophagus, and heartburn that is not responsive to proton pump inhibitor treatment. Several etiologies have been identified in patients with functional esophageal disorders, and these include esophageal hypersensitivity due to peripheral and/or central sensitisation, altered central processing of peripheral stimuli, altered autonomic activity, and psychological comorbidity such as depression and anxiety. Different antidepressants have been used as pain modulators and have demonstrated a beneficial effect on patients with the aforementioned esophageal disorders. Tricyclic antidepressants are the most commonly used class of drugs in clinical practice. Other antidepressants that have been used, some with more clinical success than others, include selective serotonin reuptake inhibitors, serotonin‐norepinephrine reuptake inhibitors, and trazodone. Other medications that have been used as pain modulators in esophageal disorders include adenosine antagonists, serotonin agonists, antiepileptics, and medications that ameliorate peripheral neuropathy. The mechanism by which many of the pain modulators confer their visceral analgesic effect remains to be fully elucidated. Regardless, their role and value in treating esophageal disorders have markedly increased in the last decade.     

Neurolytic Blocks of the Sympathetic Axis for the Treatment of Visceral Pain in Cancer

Pain due to cancer is frequently visceral, and neurolysis of the sympathetic axis has been shown to be an effective and safe method for treating this visceral pain. Several studies have documented the efficacy of neurolytic blocks both by a reduction in the intensity of pain and by a decrease in opioid consumption. Neurolysis of the sympathetic axis should be incorporated into the pain specialist's arsenal as an adjuvant to oral pharmacologic therapy.