Complex Regional Pain Syndrome (CRPS) is a constellation of symptoms describing persistent pain in a particular body region/extremity with varying degrees of autonomic dysfunction. CRPS has been divided in CRPS I (formerly reflex sympathetic dystrophy) and CRPS II (formerly causalgia). The primary difference between CRPS I and II is the absence (CRPS I) or presence (CRPS II) of nerve injury. CRPS I is associated with an inciting event (potentially minor) and the lack of nerve injury. The exact pathophysiology is an area of ongoing debate, but is felt to involve peripheral and central sensitization, release of inflammatory mediators, and some degree of sympathetic nervous system involvement.
The commonly accepted diagnostic criteria for CRPS was developed in 2007 and commonly referred to as the “Budapest Criteria”. While originally developed as criteria to assist research, they have largely become the clinical definition used in the United States for diagnosis of CRPS. Attempts to develop objective testing (sensory testing, doppler blood flow studies, triple phase bone scans) in CRPS has proved largely unsuccessful and CRPS remains a clinical diagnosis.
The treatment of complex regional pain syndrome (CRPS) is centered around a multidisciplinary team-based approach to control pain and restore function. Early diagnosis and appropriate referral are crucial to improved outcomes.
Similar to other pain syndromes, multimodal pharmacotherapy can prove useful as well for treatment of symptoms. NSAIDs, Antidepressants, and Anticonvulsants have shown to have some benefit in CRPS. While opioids as well have shown some benefit in the short term, long term benefit has yet to be established. The use of bisphosphonates is an area of promise with significant benefit shown in several RCTs.
While physical therapy remains the frontline modality, interventional pain techniques (sympathetic blocks) can prove useful to improve compliance with physical therapy where significant pain is present. Stellate Ganglion blocks are used for the arms and Lumbar Sympathetic Blocks are performed for the legs prior to physical therapy which allows for more intense physical therapy and desensitization. For patients that fail physical therapy, pharmacotherapy, and interventional pain techniques, the use of spinal cord stimulation has shown to provide benefit.