CRPS-I is a syndrome characterized by a continuing (spontaneous and/or evoked) regional pain that is seemingly disproportionate in time or degree to the usual course of pain after trauma or other lesion. The pain is regional (not in a specific nerve territory or dermatome) and usually has a distal predominance of abnormal sensory, motor, sudomotor, vasomotor/oedema and/or trophic findings. The syndrome shows variable progression over time. CRPS-I occurs after any form of trauma, particularly a fracture or soft tissue lesion. CRPS-II occurs after nerve damage.

CRPS is a rare, neuro-inflammatory syndrome characterized by intense chronic pain, swelling, tropic changes, vascular changes, and functional impairment of the limb. It can become incredibly debilitating unless diagnosed early and treated appropriately.

There is no single test for diagnosing CRPS. The best diagnostic tool is a good medical history and thorough exam. CRPS is classified as an orphan disease (less than 200,000 prevalence). It generally develops after some type of trauma such as a fracture, sprain, surgery, crush injury, or immobilization of the limb. Pain generally starts in one limb; however, it can present in the trunk (spine, abdomen, chest wall). CRPS pain is rated higher than cancer pain and amputation of a digit on the McGill Pain Index.

10 facts about CRPS

1. CRPS is more common in women than men with a ratio of 3.5:1.
2. The highest incidence of CRPS occurs in women aged 60-70 years old.
3. CRPS has been previously known by 25 other medical names.
4. Less than 2 percent of health research dollars are invested in pain research.
5. Reported CRPS after Total Knee Arthroplasty (TKA) is reported to be 21 percent at one year (Toms, 2009) with decreasing percentages at years two and three postoperatively. Among ACL reconstruction patients, the numbers appear to be lower, in the range of 4 percent (Reuben, 2004) however some estimates range that up to 13 percent of patients who undergo this procedure will develop CRPS. ​
6. Occasionally, CRPS develops without any known injury (National Institute of Neurological Disorders and Stroke, 2013)
7. According to the National Institute of Neurological Disorders and Strokes (NINDS), approximately 2 percent to 5 percent of patients with peripheral nerve injury and approximately 12 percent to 21 percent of patients with partial paralysis (on one side of the body) develop CRPS as a complication.
8. In an online RSDSA/Johns Hopkins School of medicine, individuals with CRPS reported that the syndrome frequently interfered with job (62 percent, disability rate), sleep (96 percent), mobility (86 percent), and self-care (57 percent). Remissions and relapses were both common.
9. In a recent medical history review (one year before CRPS onset), individuals who developed CRPS had more migraine, menstrual cycle-related problems, neuropathies, and asthma than individual without CRPS.
10. RSD was first described in detail in “Injuries of Nerves and Their Consequences,” a monograph published in 1872 by Dr. S. Weir Mitchell, an innovative Philadelphia physician who was also a popular poet and novelist.