CRPS July 2011 Research Update

Impaired Hand Size Estimation in CRPS (J Pain. 2011 Jul 7)

Peltz E, Seifert F, Lanz S, Müller R, Maihöfner C.

Source

Department of Neurology, University of Erlangen-Nuremberg, Erlangen, Germany.

Abstract

A triad of clinical symptoms, ie, autonomic, motor and sensory dysfunctions, characterizes complex regional pain syndromes (CRPS). Sensory dysfunction comprises sensory loss or spontaneous and stimulus-evoked pain. Furthermore, a disturbance in the body schema may occur. In the present study, patients with CRPS of the upper extremity and healthy controls estimated their hand sizes on the basis of expanded or compressed schematic drawings of hands. In patients with CRPS we found an impairment in accurate hand size estimation; patients estimated their own CRPS-affected hand to be larger than it actually was when measured objectively. Moreover, overestimation correlated significantly with disease duration, neglect score, and increase of two-point-discrimination-thresholds (TPDT) compared to the unaffected hand and to control subjects’ estimations. In line with previous functional imaging studies in CRPS patients demonstrating changes in central somatotopic maps, we suggest an involvement of the central nervous system in this disruption of the body schema. Potential cortical areas may be the primary somatosensory and posterior parietal cortices, which have been proposed to play a critical role in integrating visuospatial information. PERSPECTIVE: CRPS patients perceive their affected hand to be bigger than it is. The magnitude of this overestimation correlates with disease duration, decreased tactile thresholds, and neglect-score. Suggesting a disrupted body schema as the source of this impairment, our findings corroborate the current assumption of a CNS involvement in CRPS.

A common experience described is a sense that the affected area is somewhat different. Part of my assessment is to determine the perception of the area in comparison to an unaffected region both ‘inherently’, via sensory stimulation and 2-point discrimination. See this post. Maihofner and team have done some really goos work over the years, looking at the cortical changes in CRPS

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Complex regional pain syndrome in adults.

Rheumatology 2011

Goebel A.

Source

Pain Research Group and Centre for Immune Studies in Pain, Department of Translational Medicine, University of Liverpool and The Walton Centre NHS Trust, Liverpool, UK.

Abstract

Complex regional pain syndrome (CRPS) is a highly painful, limb-confined condition, which arises usually after trauma. It is associated with a particularly poor quality of life, and large health-care and societal costs. The causes of CRPS remain unknown. The condition’s distinct combination of abnormalities includes limb-confined inflammation and tissue hypoxia, sympathetic dysregulation, small fibre damage, serum autoantibodies, central sensitization and cortical reorganization. These features place CRPS at a crossroads of interests of several disciplines including rheumatology, pain medicine and neurology. Significant scientific and clinical advances over the past 10 years hold promise both for an improved understanding of the causes of CRPS, and for more effective treatments. This review summarizes current concepts of our understanding of CRPS in adults. Based on the results from systematic reviews, treatment approaches are discussed within the context of these concepts. The treatment of CRPS is multidisciplinary and aims to educate about the condition, sustain or restore limb function, reduce pain and provide psychological intervention. Results from recent randomized controlled trials suggest that it is possible that some patients whose condition was considered refractory in the past can now be effectively treated, but confirmatory trials are required. The review concludes with a discussion of the need for additional research.

An overview of CRPS by Andreas Goebel mentioning the MDT approach including the need for education, a fundamental starting point. Rarely does a patient come along with a good, practical understanding of either pain or CRPS as it has not been explained to them in adequate detail. Other interesting work by Andreas Goebel includes the study in 2010 that looked at the effects of intravenous immunoglobulin in CRPS (click here). The results were good although the study was small and further work is needed. However, the immune system is inherently involved in chronic pain and certainly CRPS, therefore future research in this direction is welcomed. Interestingly, some recent work looking at the immune system has linked thought processes with immune activity, developing our understanding of how we can influence this system by reducing fear and negative appraisal. This includes our education of patients and how we set up exercise programmes. Mick Thacker’s concept of movement as an antigen is both fascinating and highly relevant in our thinking of how to best plan our programmes of treatment.

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The Specificity and Mechanisms of Hemilateral Sensory Disturbances in Complex Regional Pain Syndrome.

J Pain. 2011 Jun 22

Knudsen L, Finch PM, Drummond PD.

Source

School of Psychology, Murdoch University, Perth, Western Australia.

Abstract

Hyperalgesia often extends from the affected limb to the ipsilateral forehead in patients with complex regional pain syndrome (CRPS). To investigate whether this is more common in CRPS than other chronic pain conditions, pressure-pain thresholds and sharpness to a firm bristle were assessed on each side of the forehead, at the pain site, and at an equivalent site on the contralateral side in 32 patients with chronic pain other than CRPS (neuropathic or nociceptive limb pain, radicular pain with referral to a lower limb or postherpetic neuralgia), and in 34 patients with CRPS. Ipsilateral forehead hyperalgesia to pressure pain was detected in 59% of CRPS patients compared with only 13% of patients with other forms of chronic pain. Immersion of the CRPS-affected limb in painfully cold water increased forehead sensitivity to pressure, especially ipsilaterally, whereas painful stimulation of the healthy limb reduced forehead sensitivity to pressure pain (albeit less efficiently than in healthy controls). In addition, auditory discomfort and increases in pain in the CRPS-affected limb were greater after acoustic startle to the ear on the affected than unaffected side. These findings indicate that generalized and hemilateral pain control mechanisms are disrupted in CRPS, and that multisensory integrative processes may be compromised. PERSPECTIVE: The findings suggest that hemilateral hyperalgesia is specific to CRPS, which could be diagnostically important. Disruptions in pain-control mechanisms were associated with the development of hyperalgesia at sites remote from the CRPS limb. Addressing these mechanisms could potentially deter widespread hyperalgesia in CRPS.

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Clinical features and pathophysiology of complex regional pain syndrome.

Marinus J, Moseley GL, Birklein F, Baron R, Maihöfner C, Kingery WS, van Hilten JJ.

Source

Department of Neurology, Leiden University Medical Center, Leiden, Netherlands; TREND Knowledge Consortium, Leiden, Netherlands.

Abstract

A complex regional pain syndrome (CRPS)-multiple system dysfunction, severe and often chronic pain, and disability-can be triggered by a minor injury, a fact that has fascinated scientists and perplexed clinicians for decades. However, substantial advances across several medical disciplines have recently improved our understanding of CRPS. Compelling evidence implicates biological pathways that underlie aberrant inflammation, vasomotor dysfunction, and maladaptive neuroplasticity in the clinical features of CRPS. Collectively, the evidence points to CRPS being a multifactorial disorder that is associated with an aberrant host response to tissue injury. Variation in susceptibility to perturbed regulation of any of the underlying biological pathways probably accounts for the clinical heterogeneity of CRPS.

An excellent overview of current knowledge and understanding of the mechanisms of CRPS including input from Lorimer Moseley – see the Body in Mind website

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