ABSTRACT
The application of recent statistical methods and internal and external validation techniques has recently redefined complex regional pain syndrome (CRPS) I and II. These criteria were designed to provide an objective evaluation of CRPS I and II and to distinguish it from neuropathic conditions in which significant autonomic symptoms are present. Differences of skin temperature between the affected and normal side are a measure of sympathetic vasoconstrictor activity. A difference of 1.5°C between sides has been suggested as diagnostic. Pain facilitation from immune to brain communication is known as the sickness response. This is the body’s initial nonspecific immune response to infection or injury and occurs within hours of the inciting event. In patients with acute CRPS, the extremity is warm and vasodilated. Sympathetic preganglionic neurons of the intermediolateral column of the spinal cord project to sympathetic ganglia that in turn innervate the effector cells of various tissues.
