The pathophysiology of the chronic pain cycle.

The diagnosis and treatment of chronic pain is an area in which the field of medicine is failing to offer the best possible care to patients. This article presents a clinically driven view of the condition with an emphasis on active recognition and intervention. Defining aspects of chronic pain, including the emotional and psychologic components, are introduced with regard to recognition and diagnosis. The pathophysiologic mechanisms that underlie the transition from acute pain to chronic pain are reviewed from the standpoint of treatment intervention. Finally, specific chronic pain states that affect the lower extremities are considered.