Status of immune mediators in complex regional pain syndrome type I.

Complex regional pain syndrome type I (CRPS-I) can affect an extremity after minor trauma or operation. The pathogenesis of this syndrome is unclear. It has clinical signs of severe local inflammation as a result of an exaggerated inflammatory response, but neurogenic dysregulation is also a contributor. Several studies investigated the role of inflammatory mediators and cytokines thus far; however, the results are heterogeneous and vary between different settings. This review summarizes recent study results that show a clear underlying inflammatory response at the local site, where systemic responses seem to be inconsistent. An induction of CRPS-like symptoms by application of neuroinflammatory mediators was shown recently. Local inflammation is involved in the pathophysiology of CRPS-I. We must expand our knowledge of pathophysiologic mechanisms, and we are still far away from using inflammatory markers in diagnosis and follow-up of CRPS-I.