RSD, now known as Complex Regional Pain Syndrome (CRPS) has no gold standard diagnostic procedure and relies on the knowledge and experience of the examiner, whether they be a medic or a physiotherapist. There are two types, I & II differentiated by the existence of a nerve injury (type II) or not (type I). In type I the precipitating injury can be minor such as an ankle sprain or a simple knock to the affected body part. The symptom profile that develops, underpinned by a range of better understood physiological changes within the nervous system, includes pain out of proportion to the inciting event and within a potentially expanded field (beyond a single nerve territory), trophic changes such as observed nail, skin and hair alterations, autonomic changes including altered blood flow, perception of the body part, colour, temperature (often warm initially, becoming cold as the problem proceeds) and size (actual swelling and increased perception of size). There are more signs, however considering the motor, sensory and autonomic systems is a good start point and indeed how they interact together, with other higher level factors such as cognition, fear and belief and other systems including the immune system and endocrine system - this on the basis that pain is a multisystem output produced by the brain according to the latest understanding of pain.