Patient Information from Dr David Nelson but a very good review for those not that conversant with this problem.

A myriad of terms has been used to describe post-noxious or traumatic pain accompanied by autonomic dysfunction and impaired extremity capacity. The most commonly used descriptors of this condition are reflex sympathetic dystrophy (RSD) in the United States and algodystrophy in Europe. However, the use of the term complex regional pain syndrome, as proposed by the International Association for the Study of Pain in 1993, provides categorization of the condition based upon clinical features, location, and specifics of the injury without implying mechanisms, etiology, or sympathetic maintenance
Author - L. Andrew Koman, M.D. Wake Forest University School of Medicine Department of Orthopaedic Surgery Winston-Salem, NC 27157

Complex regional pain syndrome (CRPS) may develop as a disproportionate consequence of a trauma affecting the limbs without nerve injury (CRPS I, or reflex sympathetic dystrophy [RSD]) or with obvious nerve lesions (CRPS II, or causalgia).
Synonyms and related keywords: complex regional pain syndrome, CRPS, complex regional pain syndrome I, CRPS I, reflex sympathetic dystrophy, RSD, complex regional pain syndrome II, CRPS II, causalgia, mimo-causalgia, Sudeck atrophy of bone, shoulder-hand syndrome, algoneurodystrophy, reflex dystrophy, reflex neurovascular dystrophy
Singh et al 2008

Wheeless' Textbook of Orthopaedics
“RSD” is an imprecisely used term; has been used to describe changes in soft tissue and bone;
- RSD may not involve the sympathetic nervous system and may not be the consequence of a reflex;
- 1995: IASP Consensus Conference: “Complex regional pain syndrome” replaced RSD
- CRPS Type 1: noxious event;
Type 2: nerve injury (causalgia)
- pain/hyperalgesia not limited to single nerve distribution, disproportionate to inciting event
- described as abnormal pain, swelling, vasomotor instability, contracture, and osteoporosis following injury or noxious stimulus.
- CRPS: other names - reflex sympathetic dystrophy, Sudeck’s atrophy, causalgia (minor and major), algodystrophy, shoulder-hand syndrome, post-traumatic pain syndrome, Painful post-traumatic osteoporosis, Transient migratory osteoporosis

RSD is a descriptive term meaning a complex disorder or a group of disorders that may develop as a consequence of trauma affecting the limbs, with or without an obvious nerve lesion. RSD also may develop after visceral diseases or CNS lesions or, rarely, without an obvious antecedent event. It consists of pain and related sensory abnormalities, abnormal blood flow and sweating, abnormalities in the motor system, and changes in structure of both superficial and deep tissues ("trophic" changes). Not all components need be present.
Synonyms and related keywords: acute peripheral trophoneurosis, algodystrophy, causalgia, chronic traumatic edema, mimocausalgia, neurovascular posttraumatic painful syndrome, neurovascular reflex dystrophy, neurovascular reflex sympathetic dystrophy, posttraumatic chronic edema, posttraumatic osteoporosis, posttraumatic pain syndrome, posttraumatic sympathetic dystrophy, RSD, shoulder-hand syndrome, spreading neuralgia, Sudeck atrophy, sympathalgia, thermalgia, traumatic angiospasm, traumatic vasospasm, complex regional pain syndrome type 1, CRPS
Eugenia-Daniela Hord, MD & Sajjad Mueed, MD 2006

Author: Satishchandra Kale, MD, FRCS 2005
Reflex sympathetic dystrophy (RSD) is a condition that is often described under various synonyms that point to its incompletely understood etiology. In 1864, Weir Mitchell coined the term causalgia to designate severe pain following nerve injury. In 1900, Sudeck described regional demineralization accompanying posttraumatic pain. In 1923, Leriche described vasomotor disequilibrium. In 1947, Evans introduced the term reflex sympathetic dystrophy. In 1993, the International Association for the Study of Pain renamed algodystrophy complex regional pain syndrome (also known as chronic regional pain syndrome or CRPS).
Synonyms and related keywords: RSD, algodystrophy, Sudeck atrophy, painful dysfunction syndrome, reflex neurovascular dystrophy, shoulder-hand syndrome, chronic regional pain syndrome, CRPS, causalgia, complex regional pain syndrome, sympathetically mediated pain syndrome, SMP, algodystrophy complex regional pain syndrome

Reflex sympathetic dystrophy (RSD) is an incompletely understood response of the body to an external stimulus, resulting in pain that usually is nonanatomic and disproportionate to the inciting event or expected healing response. As early as the 1930s and 1940s, a short circuit in the reflex arc between somatic afferent sensory fibers and autonomic sympathetic efferents was postulated to explain overall increased sympathetic stimulation. Currently, no specific pathologic, histologic, or biochemical markers of this condition exist. Although controversy continues regarding the term, definition, and process of diagnosis, the presence of sympathetically maintained pain is accepted as an etiology for, or at least as a significant component of, many regional pain problems.
Synonyms and related keywords: complex regional pain syndrome type I, CRPS-I, sympathetically mediated pain syndrome, SMPS, causalgia, algodystrophy, algodynia, Sudek's atrophy, Sudek atrophy, shoulder-hand syndrome, RSD
Lawrence E Holder, MD 2005

Reflex sympathetic dystrophy (RSD) is a clinical syndrome of variable course and unknown cause characterized by pain, swelling, and vasomotor dysfunction of an extremity. This condition is often the result of trauma or surgery. In 1864, Mitchell referred to this malady as causalgia, a Greek word meaning burning pain. Newer taxonomy refers to RSD as a type of complex regional pain syndrome (CRPS), which may develop after an initiating event such as trauma or surgery or may occur spontaneously.1 Under this classification, causalgia is a type of CRPS that develops after nerve injury. In patients with either of these conditions, sympathetic mediation of the pain (ie, improvement with sympathetic blockade) may or may not be evident.
Synonyms and related keywords: reflex sympathetic dystrophy, RSD, causalgia, Sudeck's atrophy, Sudeck-Leriche syndrome, minor traumatic dystrophy, major traumatic dystrophy, shoulder-hand syndrome, neurovascular dystrophy, post-traumatic vasomotor disorder, sympathetic neurovascular dystrophy, post-traumatic vasospasm, postinfarct sclerodactyly, traumatic angiospasm, transient regional osteoporosis, algodystrophy, complex regional pain syndrome, CRPS
Revis, Goldberg & Weinstein 2007