CRPS/RSD is one example of a chronic and malignant pain syndrome. No one is sure what might trigger the syndrome – it can be a light injury, or severe injury, but even carefully planned and well-executed surgery can trigger the onset of the condition. There are various notions about the pathophysiology of its cause (injury to the sympathetic nervous system in the extremities, or abnormal immune responses), and a number of explanations for why it persists (central sensitization, or a thalamocortical dysrhythmia are a few).
Some researchers think that Fibromyalgia represents a form of CRPS/RSD where fatigue and pain are the greater part of the condition – with relatively less involvement of the autonomic nervous system.
Unfortunately CRPS/RSD has become a controversial diagnosis and the object of derision – sometimes it is dismissed as freshly contrived by malingerers. It was first described in the western medical literature in 1813, and was encyclopedically defined as “causalgia” in 1864 based on the injury patterns of Civil War soldiers.