In search for the etiology of the complex regional pain syndrome

The complex regional pain syndrome is poorly elucidated. In line with this its diagnosis and clinical management have remained suboptimal. The multifaceted nature makes it a fascinating study topic for scientists with varying interests, but unraveling the etiology has been proven a laborious mission. The first notification of what could have been (what is currently named) complex regional pain syndrome (CRPS) stems from 1634, when the surgeon Ambroise Pare described that King Charles IX suffered from persistent pain and contractures of his arm following a bloodletting procedure.1 The next remarks came from the military physician Scott Mitchell and date from the American Civil War: “…Long after the trace of the effect of a wound has gone neuralgic symptoms are apt to linger, and too many carry with them throughout long years this final reminder of the battle field...”.2 The first scientific publication on CRPS was issued in 1900 from a German surgeon named Paul Sudeck.3 His name became tied to the syndrome for long (Sudecks’ dystrophy)

Applied information retrieval and multidisciplinary research: new mechanistic hypotheses in Complex Regional Pain Syndrome

Background: Collaborative efforts of physicians and basic scientists are often necessary in the investigation of complex disorders. Difficulties can arise, however, when large amounts of information need to reviewed. Advanced information retrieval can be beneficial in combining and reviewing data obtained from the various scientific fields. In this paper, a team of investigators with varying backgrounds has applied advanced information retrieval methods, in the form of text mining and entity relationship tools, to review the current literature, with the intention to generate new insights into the molecular mechanisms underlying a complex disorder. As an example of such a disorder the Complex Regional Pain Syndrome (CRPS) was chosen. CRPS is a painful and debilitating syndrome with a complex etiology that is still unraveled for a considerable part, resulting in suboptimal diagnosis and treatment. Results: A text mining based approach combined with a simple network analysis identified Nuclear Factor kappa B (NFκB) as a possible central mediator in both the initiation and progression of CRPS. Conclusion: The result shows the added value of a multidisciplinary approach combined with information retrieval in hypothesis discovery in biomedical research. The new hypothesis, which was derived in silico, provides a framework for further mechanistic studies into the underlying molecular mechanisms of CRPS and requires evaluation in clinical and epidemiological studies

The prevalence of autoantibodies in complex regional pain syndrome type i

Autoimmunity has been suggested as one of the pathophysiologic mechanisms that may underlie complex regional pain syndrome (CRPS). Screening for antinuclear antibodies (ANA) is one of the diagnostic tests, which is usually performed if a person is suspected to have a systemic autoimmune disease. Antineuronal antibodies are autoantibodies directed against antigens in the central and/or peripheral nervous system. The aim of this study was to compare the prevalence of these antibodies in CRPS patients with the normal values of those antibodies in the healthy population. Twenty seven (33%) of the 82 CRPS patients of whom serum was available showed a positive ANA test. This prevalence is significantly higher than in the general population. Six patients (7.3%) showed a positive result for typical antineuronal antibodies. This proportion, however, does not deviate from th

Cutaneous tactile allodynia associated with microvascular dysfunction in muscle

<p>Abstract</p> <p>Background</p> <p>Cutaneous tactile allodynia, or painful hypersensitivity to mechanical stimulation of the skin, is typically associated with neuropathic pain, although also present in chronic pain patients who do not have evidence of nerve injury. We examine whether deep tissue microvascular dysfunction, a feature common in chronic non-neuropathic pain, contributes to allodynia.</p> <p>Results</p> <p>Persistent cutaneous allodynia is produced in rats following a hind paw ischemia-reperfusion injury that induces microvascular dysfunction, including arterial vasospasms and capillary slow flow/no-reflow, in muscle. Microvascular dysfunction leads to persistent muscle ischemia, a reduction of intraepidermal nerve fibers, and allodynia correlated with muscle ischemia, but not with skin nerve loss. The affected hind paw muscle shows lipid peroxidation, an upregulation of nuclear factor kappa B, and enhanced pro-inflammatory cytokines, while allodynia is relieved by agents that inhibit these alterations. Allodynia is increased, along with hind paw muscle lactate, when these rats exercise, and is reduced by an acid sensing ion channel antagonist.</p> <p>Conclusion</p> <p>Our results demonstrate how microvascular dysfunction and ischemia in muscle can play a critical role in the development of cutaneous allodynia, and encourage the study of how these mechanisms contribute to chronic pain. We anticipate that focus on the pain mechanisms associated with microvascular dysfunction in muscle will provide new effective treatments for chronic pain patients with cutaneous tactile allodynia.</p

The prevalence of autoantibodies in complex regional pain syndrome type i

Autoimmunity has been suggested as one of the pathophysiologic mechanisms that may underlie complex regional pain syndrome (CRPS). Screening for antinuclear antibodies (ANA) is one of the diagnostic tests, which is usually performed if a person is suspected to have a systemic autoimmune disease. Antineuronal antibodies are autoantibodies directed against antigens in the central and/or peripheral nervous system. The aim of this study was to compare the prevalence of these antibodies in CRPS patients with the normal values of those antibodies in the healthy population. Twenty seven (33%) of the 82 CRPS patients of whom serum was available showed a positive ANA test. This prevalence is significantly higher than in the general population. Six patients (7.3%) showed a positive result for typical antineuronal antibodies. This proportion, however, does not deviate from th

Familial occurrence of complex regional pain syndrome

Genetic factors are suggested to play a role in complex regional pain syndrome (CRPS). but familial Occurrence has not been extensively studied. In the present Study we evaluated familial occurrence in Dutch patients with CRPS. Families were recruited through the Dutch Association of CRPS patients and through referral by clinicians. The number of affected members per family, the phenotypic expression and inheritance were assessed. Demographic and clinical characteristics of familial CRPS(fCRPS) patients were compared with those of sporadic CRPS (sCRPS) patients from a Dutch population-based study and with a group of sCRPS patients that was proportionally matched for referral center of the fCRPS probandi to control for referral bias. Thirty-one CRPS families with two or more affected relatives were identified, including two families with five, four With four, eight With three and 17 with two affected relatives. In comparison with sCRPS patients, fCRPS patients had a younger age at onset and more often had Multiple affected extremities and dystonia. We conclude that CRPS may occur in a familial form, but did not find a clear inheritance pattern. Patients with fCRPS develop the disease at a younger age and have a. more severe phenotype than sporadic cases, suggesting a genetic predisposition to develop CRPS. (C) 2008 European Federation of Chapters of the International Association for the Study of Pain. Published by Elsevier Ltd. All rights reserved