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Limerick G, Christo DK, Tram J, Moheimani R, Manor J, Chakravarthy K, Karri J, Christo PJ. Complex Regional Pain Syndrome: Evidence-Based Advances in Concepts and Treatments. Curr Pain Headache Rep 2023; 27:269-298. [PMID: 37421541 DOI: 10.1007/s11916-023-01130-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/29/2023] [Indexed: 07/10/2023]
Abstract
PURPOSE OF REVIEW This review presents the most current information about the epidemiology of complex regional pain syndrome (CRPS), classification and diagnostic criteria, childhood CRPS, subtypes, pathophysiology, conventional and less conventional treatments, and preventive strategies. RECENT FINDINGS CRPS is a painful disorder with multifactorial pathophysiology. The data describe sensitization of the central and peripheral nervous systems, inflammation, possible genetic factors, sympatho-afferent coupling, autoimmunity, and mental health factors as contributors to the syndrome. In addition to conventional subtypes (type I and type II), cluster analyses have uncovered other proposed subtypes. Prevalence of CRPS is approximately 1.2%, female gender is consistently associated with a higher risk of development, and substantial physical, emotional, and financial costs can result from the syndrome. Children with CRPS seem to benefit from multifaceted physical therapy leading to a high percentage of symptom-free patients. The best available evidence along with standard clinical practice supports pharmacological agents, physical and occupational therapy, sympathetic blocks for engaging physical restoration, steroids for acute CRPS, neuromodulation, ketamine, and intrathecal baclofen as therapeutic approaches. There are many emerging treatments that can be considered as a part of individualized, patient-centered care. Vitamin C may be preventive. CRPS can lead to progressively painful sensory and vascular changes, edema, limb weakness, and trophic disturbances, all of which substantially erode healthy living. Despite some progress in research, more comprehensive basic science investigation is needed to clarify the molecular mechanisms of the disease so that targeted treatments can be developed for better outcomes. Incorporating a variety of standard therapies with different modes of action may offer the most effective analgesia. Introducing less conventional approaches may also be helpful when traditional treatments fail to provide sufficient improvement.
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Affiliation(s)
- Gerard Limerick
- Division of Pain Medicine, Department of Anesthesiology & Critical Care Medicine, Johns Hopkins University School of Medicine, Baltimore, USA
- Department of Physical Medicine & Rehabilitation, Johns Hopkins University School of Medicine, Baltimore, USA
| | - Dana K Christo
- Division of General Internal Medicine, Johns Hopkins University School of Medicine, Baltimore, USA
| | - Jennifer Tram
- Department of Anesthesiology, University of California, San Diego, CA, USA
| | | | - John Manor
- Department of Physical Medicine & Rehabilitation, Johns Hopkins University School of Medicine, Baltimore, USA
| | | | - Jay Karri
- Division of Pain Medicine, Department of Anesthesiology & Critical Care Medicine, Johns Hopkins University School of Medicine, Baltimore, USA
- Department of Orthopedic Surgery, University of Maryland School of Medicine, Baltimore, MD, USA
- Department of Anesthesiology, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Paul J Christo
- Division of Pain Medicine, Department of Anesthesiology & Critical Care Medicine, Johns Hopkins University School of Medicine, Baltimore, USA.
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Saed A, Neal-Smith G, Fernquest S, Bourget-Murray J, Wood A. Management of complex regional pain syndrome in trauma and orthopaedic surgery-a systematic review. Br Med Bull 2023; 146:27-42. [PMID: 37185896 DOI: 10.1093/bmb/ldac034] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 11/13/2022] [Indexed: 05/17/2023]
Abstract
INTRODUCTION Complex regional pain syndrome (CRPS) is a neurological pain disorder that is challenging to diagnose and manage, resulting in increased morbidity and costs. It most commonly occurs following traumatic injury, such as a fracture, crush injury or surgery. Recent research has evaluated the efficacy of treatments which have contradicted previous hypotheses. This systematic review summarizes these findings to improve clinician's decision-making. SOURCES OF DATA A comprehensive search of PubMed, MEDLINE and Embase databases from inception through January 2021 was performed in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Two reviewers independently screened relevant articles discussing the management of CRPS in adult trauma patients. All prospective and retrospective studies, non-randomized comparison studies and case series were considered for inclusion. Data extraction was performed by populating a predefined data abstraction sheet. AREAS OF AGREEMENT There is strong evidence to suggest the efficacy of prompt physiotherapy, lidocaine, ketamine, bisphosphonates, sympathectomy and brachial plexus blocks in the management of CRPS. AREAS OF CONTROVERSY The latest evidence suggests that vitamin C has no significant role to play in the treatment or prevention of CRPS. GROWING POINTS A multidisciplinary team approach and early diagnosis are imperative for successful treatment of CRPS. The Budapest criteria and the British Orthopaedic Association Standards for Trauma and Orthopaedics (BOAST) guidelines should be used when diagnosing CRPS. There is currently no clear evidence of superiority in any treatment. AREAS TIMELY FOR DEVELOPING RESEARCH There are few high-quality studies that inform the best treatment modalities for CRPS. Though emerging treatments show promise, further research is needed.
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Affiliation(s)
- Abdel Saed
- Investigation Performed at the Trauma & Orthopaedic Department, Oxford Trauma Unit, John Radcliffe Hospital, Oxford, UK
| | - Greg Neal-Smith
- Investigation Performed at the Trauma & Orthopaedic Department, Oxford Trauma Unit, John Radcliffe Hospital, Oxford, UK
| | - Scott Fernquest
- Investigation Performed at the Trauma & Orthopaedic Department, Oxford Trauma Unit, John Radcliffe Hospital, Oxford, UK
| | - Jonathan Bourget-Murray
- Investigation Performed at the Trauma & Orthopaedic Department, Oxford Trauma Unit, John Radcliffe Hospital, Oxford, UK
| | - Alexander Wood
- Investigation Performed at the Trauma & Orthopaedic Department, Oxford Trauma Unit, John Radcliffe Hospital, Oxford, UK
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Lii TR, Singh V. Ketamine for Complex Regional Pain Syndrome: A Narrative Review Highlighting Dosing Practices and Treatment Response. Anesthesiol Clin 2023; 41:357-369. [PMID: 37245947 PMCID: PMC10688501 DOI: 10.1016/j.anclin.2023.03.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
This is a narrative review of intravenous ketamine infusions for the treatment of complex regional pain syndrome (CRPS). It briefly covers the definition of CRPS, its epidemiology, and other treatments before introducing ketamine as the article's focus. A summary of ketamine's evidence base and its mechanisms of action is provided. The authors then review ketamine dosages reported in peer-reviewed literature for the treatment of CRPS, and their associated duration of pain relief. The observed response rates to ketamine and predictors of treatment response are also discussed.
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Affiliation(s)
- Theresa R Lii
- Department of Anesthesiology, Perioperative and Pain Medicine, Stanford University, 450 Broadway Street, MC6343, Redwood City, CA 94063, USA
| | - Vinita Singh
- Department of Anesthesiology, Emory University, 550 Peachtree Street, Emory University Hospital Midtown, Atlanta, GA 30308, USA.
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Mangnus TJP, Dirckx M, Bharwani KD, Baart SJ, Siepman TAM, Redekop K, Dik WA, de Vos CC, Huygen FJPM. Intermittent versus continuous esketamine infusions for long-term pain modulation in complex regional pain syndrome: protocol of a randomized controlled non-inferiority study (KetCRPS-2). BMC Musculoskelet Disord 2023; 24:239. [PMID: 36991381 DOI: 10.1186/s12891-023-06258-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/31/2022] [Accepted: 02/20/2023] [Indexed: 03/31/2023] Open
Abstract
BACKGROUND Complex regional pain syndrome (CRPS) is a chronic pain condition of an extremity. While achieving pain relief in CRPS is challenging, esketamine infusions can accomplish pain relief for several weeks post-infusion in a subgroup of CRPS patients. Unfortunately, CRPS esketamine protocols are very heterogeneous in advice on dosage, administration and treatment setting. Currently, no trials are available that study differences between intermittent and continuous esketamine infusions for CRPS. With the current situation of bed shortages, it is difficult to admit patients for several consecutive days for inpatient esketamine treatments. In this study, we investigate whether 6 intermittent outpatient esketamine treatments are not inferior to a continuous 6-day inpatient esketamine treatment in establishing pain relief. In addition, several secondary study parameters will be assessed in order to investigate mechanisms responsible for pain relief by esketamine infusions. Furthermore, the cost-effectiveness will be analyzed. METHODS In this RCT, the primary objective is to demonstrate that an intermittent esketamine dosing regimen is non-inferior to a continuous esketamine dosing regimen at 3 months follow-up. We will include 60 adult CRPS patients. The inpatient treatment group receives a continuous intravenous esketamine infusion for 6 consecutive days. The outpatient treatment group receives a 6-hour intravenous esketamine infusion every 2 weeks for 3 months. Esketamine dose will be individually tailored and is started at 0.05 mg/kg/h and can be increased to a maximum of 0.2 mg/kg/h. Each patient will be followed for 6 months. The primary study parameter is perceived pain intensity, measured by an 11-point Numerical Rating Scale. Secondary study parameters are conditioned pain modulation, quantitative sensory testing, adverse events, thermography, blood inflammatory parameter, questionnaires about functionality, quality of life and mood and costs per patient. DISCUSSION If our study reveals non-inferiority between intermittent and continuous esketamine infusions, these findings can be beneficial to increase the availability and flexibility of esketamine infusions through outpatient treatments. Furthermore, the costs of outpatient esketamine infusions could be lower than inpatient esketamine infusions. In addition, secondary parameters may predict response to esketamine treatment. TRIAL REGISTRATION ClinicalTrials.gov Identifier NCT05212571 , date of registration 01-28-2022. PROTOCOL VERSION Version 3, February 2022.
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Affiliation(s)
- Thomas J P Mangnus
- Department of Anesthesiology, Center for Pain Medicine, Erasmus MC University Medical Center, Rotterdam, the Netherlands.
| | - Maaike Dirckx
- Department of Anesthesiology, Center for Pain Medicine, Erasmus MC University Medical Center, Rotterdam, the Netherlands
| | - Krishna D Bharwani
- Department of Anesthesiology, Center for Pain Medicine, Erasmus MC University Medical Center, Rotterdam, the Netherlands
| | - Sara J Baart
- Department of Biostatistics, Erasmus MC University Medical Center, Rotterdam, the Netherlands
| | - Theodora A M Siepman
- Department of Anesthesiology, Center for Pain Medicine, Erasmus MC University Medical Center, Rotterdam, the Netherlands
| | - Ken Redekop
- Institute of Health Policy & Management, Erasmus University, Rotterdam, the Netherlands
| | - Willem A Dik
- Laboratory Medical Immunology, Department of Immunology, Erasmus MC University Medical Center, Rotterdam, the Netherlands
| | - Cecile C de Vos
- Department of Anesthesiology, Center for Pain Medicine, Erasmus MC University Medical Center, Rotterdam, the Netherlands
| | - Frank J P M Huygen
- Department of Anesthesiology, Center for Pain Medicine, Erasmus MC University Medical Center, Rotterdam, the Netherlands
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Melf-Marzi A, Böhringer B, Wiehle M, Hausteiner-Wiehle C. Modern Principles of Diagnosis and Treatment in Complex Regional Pain Syndrome. DEUTSCHES ARZTEBLATT INTERNATIONAL 2022; 119:879-886. [PMID: 36482756 PMCID: PMC10011717 DOI: 10.3238/arztebl.m2022.0358] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/21/2022] [Revised: 04/21/2022] [Accepted: 10/17/2022] [Indexed: 12/15/2022]
Abstract
BACKGROUND Background: Complex regional pain syndrome (CRPS) is a relatively common complication, occurring in 5% of cases after injury or surgery, particularly in the limbs. The incidence of CPRS is around 5-26/100 000. The latest revision of the International Statistical Classification of Diseases and Related Health Problems (ICD-11) now categorizes CRPS as a primary pain condition of multifactorial origin, rather than a disease of the skeletal system or the autonomic nervous system. METHODS Method: Based on a selective search of the literature, we summarize current principles for the diagnosis and treatment of CRPS. RESULTS Results: Regional findings in CRPS are accompanied by systemic symptoms, especially by neurocognitive disorders of body perception and of symptom processing. The therapeutic focus is shifting from predominantly passive peripheral measures to early active treatments acting both centrally and peripherally. The treatment is centered on physiotherapy and occupational therapy to improve sensory perception, strength, (fine) motor skills, and sensorimotor integration/ body perception. This is supported by stepped psychological interventions to reduce anxiety and avoidance behavior, medication to decrease inflammation and pain, passive physical measures for reduction of edema and of pain, and medical aids to improve functioning in daily life. Interventional procedures should be limited to exceptional cases and only be performed in specialized centers. Spinal cord and dorsal root ganglion stimulation, respectively, are the interventions with the best evidence. CONCLUSION Conclusion: The modern principles for the diagnosis and treatment of CRPS consider both, physiological and psychological mechanisms, with the primary goal of restoring function and participation. More research is needed to strengthen the evidence base in this field.
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Affiliation(s)
- Alexandra Melf-Marzi
- Department for BG Rehabilitation; Outpatient CRPS Clinic; BG Trauma Center Murnau; Department for Anesthesiology, Intensive Care Medicine and Pain Therapy; Multimodal Pain Therapy; BG Trauma Center Murnau; Department for Neurology, Clinical Neurophysiology and Stroke Unit; BG Trauma Center Murnau; Clinic and Polyclinic for Psychosomatic Medicine and Psychotherapy, Klinikum rechts der Isar, Technical University of Munich
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Chitneni A, Patil A, Dalal S, Ghorayeb JH, Pham YN, Grigoropoulos G. Use of Ketamine Infusions for Treatment of Complex Regional Pain Syndrome: A Systematic Review. Cureus 2021; 13:e18910. [PMID: 34820225 PMCID: PMC8601938 DOI: 10.7759/cureus.18910] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/19/2021] [Indexed: 11/06/2022] Open
Abstract
This systematic review aims to review clinical studies on the use of ketamine infusion for patients with treatment-resistant complex regional pain syndrome (CRPS). The following systematic review was registered on the International Prospective Register of Systematic Reviews (PROSPERO) (CRD42021228470). Studies for the systematic review were identified through three databases: PubMed, Cumulative Index of Nursing and Allied Health Literature (CINAHL), and Cochrane Reviews. Inclusion criteria for studies consisted of randomized clinical trials or cohort studies that conducted trials on the use of ketamine infusion for pain relief in patients with CRPS. Exclusion criteria for studies included any studies that were systematic reviews, meta-analyses, case reports, literature reviews, or animal studies. In the included studies, the primary outcome of interest was the post-drug administration pain score. In this systematic review, 14 studies met the inclusion criteria and were reviewed. In these studies, the dosage of ketamine infusion used ranged from 0.15 mg/kg to 7 mg/kg with the primary indication being the treatment of CRPS. In 13 of the studies, ketamine infusion resulted in a decrease in pain scores and relief of symptoms. Patients who received ketamine infusion for treatment-resistant CRPS self-reported adequate pain relief with treatment. This suggests that ketamine infusion may be a useful form of treatment for patients with no significant pain relief with other conservative measures. Future large-scale studies, including randomized double-blind placebo-controlled trials on the use of ketamine infusion for CRPS, must be conducted in a large-scale population to further assess the effectiveness of ketamine infusion in these populations.
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Affiliation(s)
- Ahish Chitneni
- Family Medicine, Peconic Bay Medical Center/Northwell Health, Riverhead, USA.,Physical Medicine & Rehabilitation, New York-Presbyterian Hospital, New York City, USA
| | - Anand Patil
- Internal Medicine, Touro University California, Vallejo, USA
| | - Suhani Dalal
- Internal Medicine, Loma Linda University Medical Center, Loma Linda, USA
| | - Joe H Ghorayeb
- Physical Medicine & Rehabilitation, University of Medicine and Health Sciences, New York City, USA
| | - Yolanda N Pham
- Internal Medicine, Loyola University Chicago Stritch School of Medicine, Maywood, USA
| | - Gregory Grigoropoulos
- Internal Medicine, Loyola University Chicago Stritch School of Medicine, Maywood, USA
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Schwenk ES, Pradhan B, Nalamasu R, Stolle L, Wainer IW, Cirullo M, Olsen A, Pergolizzi JV, Torjman MC, Viscusi ER. Ketamine in the Past, Present, and Future: Mechanisms, Metabolites, and Toxicity. Curr Pain Headache Rep 2021; 25:57. [PMID: 34269883 DOI: 10.1007/s11916-021-00977-w] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/21/2021] [Indexed: 12/01/2022]
Abstract
PURPOSE OF REVIEW While ketamine's analgesia has mostly been attributed to antagonism of N-methyl-D-aspartate receptors, evidence suggests multiple other pathways are involved in its antidepressant and possibly analgesic activity. These mechanisms and ketamine's role in the nociplastic pain paradigm are discussed. Animal studies demonstrating ketamine's neurotoxicity have unclear human translatability and findings from key rodent and human studies are presented. RECENT FINDINGS Ketamine's metabolites, and (2R,6R)-hydroxynorketamine in particular, may play a greater role in its clinical activity than previously believed. The activation of α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) and the mammalian target of rapamycin by ketamine are mechanisms that are still being elucidated. Ketamine might work best in nociplastic pain, which involves altered pain processing. While much is known about ketamine, new studies will continue to define its role in clinical medicine. Evidence supporting ketamine's neurotoxicity in humans is lacking and should not impede future ketamine clinical trials.
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Affiliation(s)
- Eric S Schwenk
- Department of Anesthesiology, Sidney Kimmel Medical College at Thomas Jefferson University, 111 South 11th Street, Gibbon Building, 8290, Philadelphia, PA, 19107, USA.
| | - Basant Pradhan
- Psychiatry & Pediatrics, Cooper Medical School of Rowan University, Camden, NJ, USA
| | - Rohit Nalamasu
- Department of Physical Medicine and Rehabilitation, University of Nebraska Medical Center, Omaha, NE, USA
| | | | | | - Michael Cirullo
- Department of Anesthesiology, Thomas Jefferson University Hospital, Philadelphia, PA, USA
| | - Alexander Olsen
- Department of Anesthesiology, Sidney Kimmel Medical College at Thomas Jefferson University, 111 South 11th Street, Gibbon Building, 8290, Philadelphia, PA, 19107, USA
| | | | - Marc C Torjman
- Department of Anesthesiology, Sidney Kimmel Medical College at Thomas Jefferson University, 111 South 11th Street, Gibbon Building, 8290, Philadelphia, PA, 19107, USA
| | - Eugene R Viscusi
- Department of Anesthesiology, Sidney Kimmel Medical College at Thomas Jefferson University, 111 South 11th Street, Gibbon Building, 8290, Philadelphia, PA, 19107, USA
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Mangnus TJP, Dirckx M, Bharwani KD, de Vos CC, Frankema SPG, Stronks DL, Huygen FJPM. Effect of intravenous low-dose S-ketamine on pain in patients with Complex Regional Pain Syndrome: A retrospective cohort study. Pain Pract 2021; 21:890-897. [PMID: 34233070 PMCID: PMC9291497 DOI: 10.1111/papr.13056] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2021] [Revised: 06/14/2021] [Accepted: 06/30/2021] [Indexed: 12/21/2022]
Abstract
Objective The objective of this study was to assess the effectiveness of a low‐dose intravenous S‐ketamine treatment on refractory pain in patients with Complex Regional Pain Syndrome (CRPS). Methods In this retrospective study, patients with CRPS who received intravenous S‐ketamine from March 2010 to April 2019 were included. According to our inpatient protocol, S‐ketamine dose was increased until pain reduction was achieved or side effects were observed. Maximum dose was 14 mg/h and treatment duration was 7 days. Primary outcome parameters were pain scores (Numeric Rating Scale) at baseline (T0), end of infusion (T1), and approximately 4 weeks postinfusion (T2). Patients were categorized as responder/nonresponder at T1 and T2. Patients were considered a responder in case there was pain score reduction of greater than or equal to 2 points or if treatment was reported as successful. Results Forty‐eight patients were included. Mean disease duration was 5 years (interquartile range [IQR] = 6 years). Median pain score significantly decreased from 8 (IQR = 2) at T0 to 6 (IQR = 4) at T1 (p < 0.001). At T1, 62% of the patients were responders. At T2, 48% of the patients remained a responder. A significant proportion of the responders at T1 turned into nonresponders at T2 (p = 0.03). Conclusion In a group of patients with CRPS with refractory pain, low‐dose intravenous S‐ketamine treatment resulted in effective pain relief during infusion. Although a significant proportion of initial responders became nonresponders at follow‐up, half of the patients were still a responder at ~ 4 weeks postinfusion. Further research is needed to investigate mechanisms responsible for pain relief by S‐ketamine infusions and to ascertain possible predictors of response to the treatment.
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Affiliation(s)
- Thomas J P Mangnus
- Center for Pain Medicine, Erasmus MC University Medical Center, Rotterdam, The Netherlands
| | - Maaike Dirckx
- Center for Pain Medicine, Erasmus MC University Medical Center, Rotterdam, The Netherlands
| | - Krishna D Bharwani
- Center for Pain Medicine, Erasmus MC University Medical Center, Rotterdam, The Netherlands
| | - Cecile C de Vos
- Center for Pain Medicine, Erasmus MC University Medical Center, Rotterdam, The Netherlands
| | - Sander P G Frankema
- Center for Pain Medicine, Erasmus MC University Medical Center, Rotterdam, The Netherlands
| | - Dirk L Stronks
- Center for Pain Medicine, Erasmus MC University Medical Center, Rotterdam, The Netherlands
| | - Frank J P M Huygen
- Center for Pain Medicine, Erasmus MC University Medical Center, Rotterdam, The Netherlands
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Cha M, Lee KH, Kwon M, Lee BH. Possible Therapeutic Options for Complex Regional Pain Syndrome. Biomedicines 2021; 9:biomedicines9060596. [PMID: 34074044 PMCID: PMC8225181 DOI: 10.3390/biomedicines9060596] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2021] [Revised: 05/18/2021] [Accepted: 05/22/2021] [Indexed: 11/18/2022] Open
Abstract
Complex regional pain syndrome (CRPS) describes an array of painful conditions that are characterized by continuing regional pain. CRPS comprises severe and inappropriate pain in cases of complete recovery after trauma. Research on the pharmacological treatment of CRPS, however, has not been well investigated. In this study, we compared the pain relief effects of different drugs (URB597, pyrrolidine dithiocarbamate, and hydralazine) in a rat model of chronic post-ischemic pain-induced CRPS. After drug injection, CRPS-induced mechanical allodynia was significantly recovered. After three repetitive drug injections, mechanical sensitivity generally improved as hyper-nociception subsided. Reduced Nav1.7 expression at dorsal root ganglions (DRGs) was observed in the drug treatment groups. Neural imaging analysis revealed decreased neural activity for each drug treatment, compared to vehicle. In addition, treatments significantly reduced IL-1β, IL-6, and TNFα expression in DRGs. These results indicated that drugs could reduce the expression of inflammatory factors and alleviate the symptoms of chronic post-ischemic pain-induced CRPS.
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Affiliation(s)
- Myeounghoon Cha
- Department of Physiology, College of Medicine, Yonsei University, Seoul 03722, Korea
- Correspondence: (M.C.); (B.H.L.); Tel.: +82-2-2228-2729 (M.C.)
| | - Kyung Hee Lee
- Department of Dental Hygiene, Division of Health Science, Dongseo University, Busan 47011, Korea;
| | - Minjee Kwon
- Department of Nursing, Kyungil University, Gyeongsan 38428, Korea;
| | - Bae Hwan Lee
- Department of Physiology, College of Medicine, Yonsei University, Seoul 03722, Korea
- Brain Korea 21 PLUS Project for Medical Science, College of Medicine, Yonsei University, Seoul 03722, Korea
- Correspondence: (M.C.); (B.H.L.); Tel.: +82-2-2228-2729 (M.C.)
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