The National Institute of Neurological Disorders and Stroke defines Complex Regional Pain Syndrome (CRPS) as a chronic pain condition most often affecting one of the limbs (arms, legs, hands, or feet), usually after an injury or trauma to that limb. CRPS is believed to be caused by damage to, or malfunction of, the peripheral and central nervous systems. The central nervous system is composed of the brain and spinal cord, and the peripheral nervous system involves nerve signaling from the brain and spinal cord to the rest of the body. CRPS is characterized by prolonged or excessive pain and mild or dramatic changes in skin color, temperature, and/or swelling in the affected area.
Complex Regional Pain Syndrome is also known as Causalgia (Complex I) and/or Reflex Sympathetic Dystrophy (RSD) (Complex II), and Sudeck’s Syndrome.