Basic guide to chronic pain assessment: from neurophysiology to bedside.

Chronic musculoskeletal pain is a highly prevalent condition that is commonly encountered in both general and specialist practice. Nonetheless, it still represents a significant challenge to the practitioners because of the lack of substantial evidence-based guidance. This review aimed to summarize the main pathophysiological mechanisms of chronic pain offering a mechanism-oriented approach to diagnosis and management. We believe that a basic knowledge of the physical signs and symptoms of these mechanisms could empower the clinician to choose appropriate medication and identify high-risk pain patients. Central sensitization and neuropathic features may arise in previously nociceptive and inflammatory pain syndromes. Central sensitization is a functional remodeling of the spinal cord, where light touch afferents are recruited by nociceptive second-order neurons. Neuropathic features include both negative signs, such as reduced perception of vibration and touch, and positive symptoms, such as paroxysmal electric shock pain, due to ectopic discharge. These phenomena are the neurobiological basis of the commonly defined refractory chronic pain. Early detection and specific treatment of these mechanisms are required in order to restrain the reinforcement of pronociceptive remodeling of the nervous system.