Prasad Md A, Chakravarthy Md K. Review of complex regional pain syndrome and the role of the neuroimmune axis.
Mol Pain 2021;
17:17448069211006617. [PMID:
33788654 PMCID:
PMC8020088 DOI:
10.1177/17448069211006617]
[Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Background
Complex regional pain syndrome (CRPS) is a progressive and painful disease of
the extremities that is characterized by continuous pain inconsistent with
the initial trauma. CRPS is caused by a multi-mechanism process that
involves both the peripheral and central nervous system, with a prominent
role of inflammation in CRPS pathophysiology. This review examines what is
currently known about the CRPS inflammatory and pain mechanisms, as well as
the possible impact of neurostimulation therapies on the neuroimmune axis of
CRPS.
Study design
A narrative review of preclinical and clinical studies provided an overview
of the pain and inflammatory mechanisms in CRPS and addressed the effect of
neurostimulation on immunomodulation.
Methods
A systematic literature search was conducted based on the PRISMA guidelines
between September 2015 to September 2020. Data sources included relevant
literature identified through searches of PubMed, Embase and the Cochrane
Database of Systematic Reviews.
Results
Sixteen preclinical and eight clinical studies were reviewed. Preclinical
studies identified different mechanisms of pain development in the acute and
chronic CRPS phases. Several preclinical and clinical studies investigating
inflammatory mechanisms, autoimmunity, and genetic profiles in CRPS,
supported a role of neuroinflammation in the pathophysiology of CRPS. The
immunomodulatory effects of neurostimulation therapy is still unclear,
despite clinical improvement in the CRPS patients.
Conclusions
Increasing evidence supports a role for inflammation and neuroinflammation in
CRPS pathophysiology. Preliminary neurostimulation findings, together with
the role of (neuro)inflammation in CRPS, seems to provide a compelling
rationale for its use in CRPS pain treatment. The possible immunomodulatory
effects of neurostimulation opens new therapeutic possibilities, however
further research is needed to gain a better understanding of the working
mechanisms.
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