MECHANISM OF RSD: Reflex Sympathetic Dystrophy (Complex Regional Pain)

Original injury initiates a pain impulse carried by sensory nerves to the central nervous system. The pain impulse in turn triggers an impulse in the sympathetic nervous system which returns to the original site of injury. The sympathetic impulse triggers the inflammatory response causing changes in the soft tissue including blood vessels. Eventually, leading to swelling, temperature changes, color changes and increased pain. The pain appears to become entrained in the patient's nervous system, establishing a cycle of pain, swelling, color changes and inability to move the affected limb. Resulting in burning, stinging pain. Swelling eventually gives way to atrophy of soft tissue.