Complex Regional Pain Syndrome

Complex regional pain syndrome (CRPS), formerly referred to as reflex sympathetic dystrophy (RSD) or causalgia, is a complex clinical entity. Most authors consider it a neuropathic pain disorder with some autonomic features and without a single pathognomonic test or marker [Patterson et al., J Hand Surg [Am] 36:1553–1562, 2011; Bruehl, Anesthesiology 113:713–725, 2010]. Nevertheless, the definition of neuropathic pain has been questioned lately [Naleschinski and Baron, Curr Pain Headache Rep 14:196–202, 2010] because there are many mechanisms proposed for this disease, as we explain in this chapter. CRPS is divided into two types: Type I and Type II. A third diagnostic suptype called CRPS not otherwise specified (CRPS_NOS) has been recommended for patients who do not fully meet the new clinical criteria of Types I and II and whose signs and symptoms could not better be explained by another diagnosis. This chapter describes the salient features of CRPS in all three types.