Complex Regional Pain Syndrome
Complex regional pain syndrome (CRPS), formerly reflex sympathetic dystrophy (RSD) or "causalgia", reflex neurovascular dystrophy (RND), or amplified musculoskeletal pain syndrome (AMPS), is a chronic systemic disease characterized by severe pain, swelling, and changes in the skin. CRPS is expected to worsen over time. It often initially affects an arm or a leg and often spreads throughout the body; 92% of patients state that they have experienced a spread, and 35% of patients report symptoms in their whole body. Recent evidence has led to the conclusion that Complex Regional Pain Syndrome is a multifactorial disorder with clinical features of neurogenic inflammation, nociceptive sensitisation (which causes extreme sensitivity or allodynia), vasomotor dysfunction, and maladaptive neuroplasticity, generated by an aberrant response to tissue injury. Treatment is complicated, involving drugs, physical therapy, psychologic treatments, and neuromodulation and usually unsatisfactory, especially if begun late.
CRPS is associated with dysregulation of the central nervous system and autonomic nervous system resulting in multiple functional loss, impairment, and disability. The International Association for the Study of Pain has proposed dividing CRPS into two types based on the presence of nerve lesion following the injury.
CRPS has the unfortunate honour of being described as being one of the most painful long term conditions, scoring 42 out of a possible 50 on the McGill pain scale, above such events as amputation and childbirth. Lack of social awareness has inspired patients to campaign for more widespread knowledge of CRPS, and lack of clinical awareness has led to the creation of support groups seeking to self-educate with the latest research.