Epidemiology, pathogenesis, and imaging of arthritis in children.

Juvenile idiopathic arthritis is a broad term used to describe a series of chronic arthritis occurring in children younger than 16 years of age. Even though the cause is not fully understood, several clues regarding the pathogenesis have been found. Diagnosis of the different types of juvenile idiopathic arthritis is made clinically, and imaging plays a role in answering specific questions pertaining to disease classification, staging, and outcome of treatment options.