As in any other chronic pain syndrome, the brain likely becomes chronically stimulated with pain, and late amputation may not work as well as it might be expected. In a survey of 15 patients with CRPS type 1, 11 responded that their lives were better after amputation. Since this is the ultimate treatment of a painful extremity, it should be left as a last resort. Prognosis
The prognosis in CRPS is improved with early and aggressive treatment; with the risk of chronic, debilitating pain being reduced with the early treatment. If treatment is delayed, however, the disorder can quickly spread to the entire limb, and changes in bone, nerve, and muscle may become irreversible. The prognosis is worse with the chronic "cold" form of CRPS and with CRPS affecting the upper extremities. Disuse of the limb after an injury or psychological distress related to an injury are also associated with a poorer prognosis in CRPS. Some cases of CRPS may resolve spontaneously (with 74% of patients undergoing complete resolution of symptoms (often spontaneously) in a population based study in Minnesota), but others may develop chronic pain for many years. Once one is diagnosed with CRPS, should it go into remission, the likelihood of it resurfacing after going into remission is significant. Taking precautions and seeking immediate treatment upon any injury is important. Epidemiology
CRPS can occur at any age, with the average age at diagnosis being 42.
Intramuscular botulinum injections may benefit people with symptoms localized to one extremity. Ketamine
Ketamine, a dissociative anesthetic, appears promising as a treatment for CRPS. It may be used in low doses if other treatments have not worked. No benefit on either function or depression, however, has been seen. Bisphosphonate treatment
As of 2013, high-quality evidence supports the use of bisphosphonates (either orally or via IV infusion) in the treatment of CRPS. Bisphosphonates inhibit osteoclasts which are cells involved in the resorption of bone. Bone remodeling, via osteoclast activity in resorption of bone, is thought to sometimes be hyperactive in CRPS. It is hypothesized that bone resorption causes acidification of the intercellular milieu and this activates nerves involved in nociception that densely innervate bone causing pain; therefore inhibiting bone resorption and remodeling is thought to help with regards to pain in CRPS. CRPS involving high levels of bone resorption, as seen on bone scan, is more likely to respond to bisphosphonate therapy. Opioids
Opioids such as oxycodone, morphine, hydrocodone, and fentanyl have a controversial place in treatment of CRPS. These drugs must be prescribed and monitored under close supervision of a physician, as these drugs will lead to physical dependence and can lead to addiction. Thus far, no long-term studies of oral opioid use in treating neuropathic pain, including CRPS, have been performed. The consensus among experts is that opioids should not be a first line therapy and should only be considered after all other modalities (non-opioid medications, physical therapy, and procedures) have been trialed.