Complex Regional Pain Syndrome (CRPS) is the current diagnostic label for the inflammatory and neuropathic pain syndrome known as Reflex Sympathetic Dystrophy (RSD) and Causalgia.  CRPS is principally characterized by involvement of the autonomic nervous system and it describes an array of painful conditions characterized by a continuing regional pain disproportionate in time and/or degree to the usual course of any known trauma or other lesion.  Despite being regional pain, the pain may spread and it usually has a distal predominance of abnormal sensory, motor, sudomotor, vasomotor, and/or trophic findings.  The syndrome shows variable progression over time.

Complex Regional Pain Syndrome (CRPS) Type I – Reflex Sympathetic Dystrophy (RSD)

CRPS Type I starts with an initiating noxious event, or a cause of immobilization. There then develops continuing pain and/or pain resulting from a stimulus (as a light touch of the skin) which would not normally provoke pain, or increased sensitivity to pain or enhanced intensity of pain sensation with which the pain is disproportionate to any inciting event. There must be evidence at some time of edema, changes in skin blood flow (skin color changes, skin temperature changes different from the homologous body part), or abnormal sudomotor (of, relating to, or being nerve fibers controlling the activity of sweat glands) activity in the region of the pain. This diagnosis is excluded by the existence of conditions that would otherwise account for the degree of pain and dysfunction.

Complex Regional Pain Syndrome (CRPS) Type II – Causalgia

CRPS Type II develops with continuing pain and/or pain resulting from a stimulus (as a light touch of the skin) which would not normally provoke pain, or increased sensitivity to pain or enhanced intensity of pain sensation with which the pain is disproportionate to any inciting event after a nerve injury, not necessarily limited to the distribution of the injured nerve. There must be evidence at some time of edema, changes in skin blood flow (skin color changes, skin temperature changes different from the homologous body part), or abnormal sudomotor (of, relating to, or being nerve fibers controlling the activity of sweat glands) activity in the region of pain. This diagnosis is excluded by the existence of conditions that would otherwise account for the degree of pain and dysfunction.