Complex regional pain syndrome — phenotypic characteristics and potential biomarkers

Abstract

Complex regional pain syndrome (CRPS) is a pain condition that usually affects a single limb, often following an injury. The underlying pathophysiology seems to be complex and probably varies between patients. Clinical diagnosis is based on internationally agreed-upon criteria, which consider the reported symptoms, presence of signs and exclusion of alternative causes. Research into CRPS biomarkers to support patient stratification and improve diagnostic certainty is an important scientific focus, and recent progress in this area provides an opportunity for an up-to-date topical review of measurable disease-predictive, diagnostic and prognostic parameters. Clinical and biochemical attributes of CRPS that may aid diagnosis and determination of appropriate treatment are delineated. Findings that predict the development of CRPS and support the diagnosis include trauma-related factors, neurocognitive peculiarities, psychological markers, and local and systemic changes that indicate activation of the immune system. Analysis of signatures of non-coding microRNAs that could predict the treatment response represents a new line of research. Results from the past 5 years of CRPS research indicate that a single marker for CRPS will probably never be found; however, a range of biomarkers might assist in clinical diagnosis and guide prognosis and treatment.

Transfer of complex regional pain syndrome to mice via human autoantibodies is mediated by interleukin-1–induced mechanisms

“…CRPS is usually triggered by trauma to the distal regions of a limb and is further associated with limb-restricted edema; sensory, vasomotor, sudomotor, motor, and trophic abnormalities; and profound sensory central nervous system (CNS) reorganization (1). In CRPS, typically no or only minimal tissue destruction occurs (2), and although morphological change, such as disuse atrophy, can sometimes be observed, this is not thought to explain the experienced intense pain (3). The underlying pathophysiological mechanisms are poorly understood.…”

“…Investigation of autoantibody contribution to other unexplained chronic pain syndromes seems warranted. central pathophysiological mechanisms underlying CRPS, reliable and validated animal models are desperately needed (2).…”

Standards for the diagnosis and management of complex regional pain syndrome: Results of a European Pain Federation task force

“…The aetiology of CRPS is likely multifactorial (Birklein et al, ). It is thought to be pathological not psychopathological in origin (Beerthuizen et al, ; Beerthuizen, van 't Spijker, Huygen, Klein, & de Wit, ).…”

“…Complex regional pain syndrome (CRPS) is a painful and disabling post-traumatic primary pain disorder affecting, usually, distal limbs (Birklein, Ajit, Goebel, Perez, & Sommer, 2018;Marinus et al, 2011). Signs and symptoms are normally restricted to the affected limb but can spread (van Rijn et al, 2011).…”

Sub-Optimal Learning of Tactile-Spatial Predictions in Patients with Complex Regional Pain Syndrome

“…Complex regional pain syndrome (CRPS) is characterised by disproportionate pain that is usually initiated by peripheral trauma to a limb (Birklein et al, 2018). The later stages of the disorder are characterised mainly by intractable pain that is poorly understood.…”