G90.7: Complex regional pain syndrome, other and unspecified type

Complex regional pain syndrome is a unique type of chronic pain condition that generally affects one limb, typically an arm, leg, hand or foot. It arises unexpectedly, usually after an injury or trauma to the limb. The pain is generally disproportionate to the original injury. The key characteristic of complex regional pain syndrome is continuous, intense pain that is worse than what would be expected from the original injury. Patients may also experience changes in skin temperature and color, abnormal sweating, and symptoms that may spread to the entire limb or even to the other extremity. Despite substantial scientific research, the exact cause of complex regional pain syndrome is not completely understood. It's commonly believed a dysfunctional interaction between the central and peripheral nervous systems, coupled with inappropriate inflammatory responses, might be responsible for this condition.