Although the two terms are used interchangeably, the medical community refers to it as Complex Regional Pain Syndrome (CRPS).
In 1994, researchers and physicians from the International Association for the Study of Pain (IASP) reclassified the terms. These are:
- CRPS type-I, which used to be called RSD (Reflex Sympathetic Dystrophy).
- CRPS type-II, which refers to people previously diagnosed as causalgia, who also have sustained nerve injuries.
The National Pain Foundation goes on to say that the actual cause of RSD/CRPS is still not known and while many people develop the syndrome in similar ways, there is no single known explanation. Symptoms may come and go in the early stages and it is unknown whether some individuals are more susceptible to CRPS than others.
A number of factors are linked to CRPS, but the leading culprit appears to be mild to severe trauma such as injuries or surgery. Something as simple as a sprain can lead to CRPS. Many people who sustain some type of injury may show signs of CRPS, while others become affected after surgery or after experiencing a painful event, such as a heart attack or an infection in an extremity such as an arm or leg. People with neurologic disorders, such as multiple sclerosis, can also develop CRPS, as can those with more chronically painful conditions such as carpal tunnel syndrome.
A severe type of this disorder, CRPS type II, may develop when people injure a nerve or nerves in an extremity such as an arm, leg or foot. Examples of this type of injury are gunshot wounds and crush injuries. Nerve injuries often are characterized by numbness or tingling and/or sharp, shooting and aching pain in the skin supplied by the injured nerve. This kind of pain is described as “neuropathic” pain and can be confined to a small area of the body. CRPS is likely to be occurring when that pain spreads to other parts of the extremity and beyond and the autonomic nervous system becomes disordered.
People with CRPS can experience a wide variety of symptoms besides pain and autonomic dysregulation, especially in the early stages of the disorder. These may include skin discoloration, muscle spasms, swelling and stiffness, feelings of heat or cold, dryness or excessive sweating in the involved area, excessive hair growth and xcessive skin sensitivity to even the light touch of clothing (a symptom doctors call allodynia). There also can be extreme sensitivity to temperature and joint movement. In the later stages severe complications, such as persistent pain, muscle atrophy and a decrease in regional bone density, occasionally with fractures (osteopinia), may occur.
According to the Reflex Sympathetic Dystrophy Syndrome Association of America (RSDSA), the future is looking brighter for people with CRPS due to promising research underway at institutions in the United States and throughout the world. This research involves studying the basic processes that cause the disorder as well as developing more effective treatments for CRPS.