Complex Regional Pain Syndrome.

Complex regional pain syndrome (CRPS) is a rare, chronic pain disorder. It is challenging for patients and physicians because it leads to significant morbidity due to chronic pain that may last for years. CRPS typically develops four to six weeks after direct trauma, such as an injury or surgery, and causes pain that is out of proportion to the inciting injury. It is associated with multiple physiologic mechanisms, affecting skin texture or localized sensory, motor, sudomotor, and vasomotor pathways. The diagnosis is made clinically using standardized diagnostic criteria. Ancillary testing is not necessary for the diagnosis of CRPS but can be useful to rule out alternative diagnoses. There are two types of CRPS, type 1 and type 2, although treatment is the same for both. There is no single proven treatment modality for CRPS, and there have been no large randomized controlled studies of CRPS treatments. Most treatments are based on studies of their use for other types of neuropathic pain. The mainstay of treatment is to improve function of the affected body part and to decrease pain; therefore, treatment requires multiple modalities, including medications, behavioral health interventions, and referral to a pain specialist.