CRPS papers February 2012

Welcome to the early February literature review, a run-down of the latest papers addressing complex regional pain syndrome.

Clin Med. 2011 Dec;11(6):596-600.

Complex regional pain syndrome in adults: concise guidance.


King’s College London School of Medicine.


Complex regional pain syndrome (CRPS) is a debilitating, painful condition in a limb associated with sensory, motor, autonomic, skin and bone abnormalities. Pain is typically the leading symptom, but is often associated with limb dysfunction and psychological distress. Prompt diagnosis and early treatment is required to avoid secondary physical problems related to disuse of the affected limb and the psychological consequences of living with undiagnosed chronic pain. UK guidelines have recently been developed for diagnosis and management in the context of primary and secondary care. The purpose of this concise guideline is to draw attention to these guidelines. Information in this article has been extracted from the main document and adapted to inform the management of CRPS as it presents to physicians in the course of their daily practice.


Rheumatology (Oxford). 2011 Oct;50(10):1739-50. Epub 2011 Jun 28.

Complex regional pain syndrome in adults.


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


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.


J Neural Transm. 2011 Apr;118(4):599-603. Epub 2010 Dec 29.

Thermal hypesthesia in patients with complex regional pain syndrome related dystonia.


Department of Neurology, Leiden University Medical Center, P.O. Box 9600, 2300 RC, Leiden, The Netherlands.


The quantitative thermal test showed cold and warmth hypesthesia without increased heat pain sensitivity in the affected limbs of complex regional pain syndrome (CRPS) patients with tonic dystonia (n = 44) in comparison with healthy controls with a similar age and sex distribution (n = 35). The degrees of cold and warmth hypesthesia were strongly correlated. We conclude that dysfunction in small nerve fiber (i.e., C and Aδ) processing is present in patients with CRPS-related dystonia.


Musculoskeletal Care. 2011 Jun 12. doi: 10.1002/msc.211. [Epub ahead of print]

An Exploration of the Support Person’s Perceptions and Experiences of Complex Regional Pain Syndrome and the Rehabilitation Process.


University of Plymouth, Plymouth, UK.


We explored the perceptions and experiences of those who support a relative or friend with complex regional pain syndrome (CRPS), a chronic pain condition of unknown aetiology usually affecting a single limb. Semi-structured interviews were analysed using interpretative phenomenological analysis, and four superordinate themes are presented here. These themes describe the efforts of carers to make sense of CRPS and the rehabilitation process, to be sensitive to the discomfort of the person with CRPS and to respond in an attuned and helpful way. CRPS had become integrated into the carers’ lives as they sought to monitor, protect and motivate the person they supported. The themes are discussed in relation to each other and to extant literature, including work on social support and adjustment to chronic illness, and the clinical implications are explored.

RS comment: I actively encourage participation of significant other(s) in the treatment process. Behaviours of the sufferer are very likely to be influenced by the partner/spouse, hence this dynamic requires attention. This maybe in the form of joint education sessions or simply attendance of the sessions to develop understanding and positive affirmations.


Pain. 2012 Jan 14. [Epub ahead of print]

Metallothionein deficiency in the injured peripheral nerves of complex regional pain syndrome as revealed by proteomics.


Department of Biomedical Engineering, Sapporo Medical University School of Medicine, Sapporo, Japan; Department of Orthopaedic Surgery, Sapporo Medical University School of Medicine, Sapporo, Japan.


Complex regional pain syndrome (CRPS) is characterized by persistent and severe pain after trauma or surgery; however, its molecular mechanisms in the peripheral nervous system are poorly understood. Using proteomics, we investigated whether injured peripheral nerves of CRPS patients have altered protein profiles compared with control nerves. We obtained nerve samples from 3 patients with CRPS-2 who underwent resection of part of an injured peripheral nerve. Sural nerves from fresh cadavers with no history of trauma or neuropathic pain served as controls. Proteomic analysis showed that the number and functional distribution of proteins expressed in CRPS and control nerves was similar. Interestingly, metallothionein was absent in the injured nerves of CRPS-2, although it was readily detected in control nerves. Western blotting further confirmed the absence of metallothionein in CRPS-2 nerves, and immunohistochemistry corroborated the deficiency of metallothionein expression in injured nerves from 5 of 5 CRPS patients and 2 of 2 patients with painful neuromas. In contrast, all control nerves, including 5 sural nerves from fresh cadavers and 41 nerves obtained from surgically resected tumors, expressed MT. Furthermore, expression of S100 as a marker for Schwann cells, and neurofilament M as a marker of axons was comparable in both CRPS-2 and controls. Metallothioneins are zinc-binding proteins that are probably involved in protection against injury and subsequent regeneration after CNS damage. Their absence from the injured peripheral nerves of patients with CRPS-2 suggests a potential pathogenic role in generating pain in the damaged peripheral nerves.


Rev Bras Anestesiol. 2011 Jul-Aug;61(4):425-33.

Incidence of regional pain syndrome after carpal tunnel release. Is there a correlation with the anesthetic technique?


Rehabilitation Sciences, Anesthesiologist of Hospital SARAH, Brasília.



Complex regional pain syndrome (CRPS) previously known as reflex sympathetic dystrophy refers to a set of signs and symptoms that include pain, increased sweating, and vasomotor instability. Pain is usually triggered by a noxious stimulus in a peripheral nerve, which is disproportionate to the triggering stimulus. Its development after surgery is not uncommon varying with the type of intervention. An incidence of 2.1 to 5% has been reported after carpal tunnel release (CTR). Sympathetic blockade may prevent the onset of CRPS. However, there is no study validating this technique to prevent CRPS after CTR. The objective of the present study was to define the incidence of CRPS after CTR and its relationship with four anesthetic techniques.


Patients were randomly distributed to undergo one of the following techniques: general anesthesia, regional intravenous anesthesia with lidocaine, regional intravenous anesthesia with lidocaine and clonidine, or axillary plexus block. Postoperatively, they were followed-up by a nurse who was unaware of the anesthetic technique used, and follow-up was done through electronic patient records for up to 6 months after the anesthesia. During this period signs and symptoms typical of CRPS were investigated and, if positive, treatment was instituted. A descriptive evaluation using the chi-square test was performed.


Three-hundred and one patients were investigated. Twenty-five of them developed CRPS, an incidence of 8.3%. Predominance was not observed among the anesthetic techniques used. Other factors such as smoking, profession, and other concomitant diseases were also investigated, and none showed a relationship with the development of post-CTR CRPS.


Complex regional pain syndrome has an incidence of 8.3% after CTR surgery without association with the anesthetic techniques investigated.



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