Juvenile idiopathic arthritis A. clinical features

Abstract

Juvenile idiopathic arthritis (JIA) is the most common form of childhood arthritis and one of the more common chronic childhood illnesses. As the term indicates, the cause is unknown. In fact, JIA is an umbrella term that refers to a group of disorders that have in common chronic arthritis. Diagnosis requires a combination of data from history, physical examination, and laboratory testing. For the vast majority of patients with JIA, the immunogenetic associations, clinical course, and functional outcome are quite different from adult-onset rheumatoid arthritis (RA). However, approximately 5% to 10% of those with JIA (those classified as polyarthritis rheumatoid factor positive) have a disease that resembles adult-onset RA much more than other types of JIA. The JIA nomenclature has in most instances replaced the older classification for chronic idiopathic arthritis in childhood-juvenile rheumatoid arthritis (JRA). The differences and similarities in the two classifications will be discussed below. In fact, this is the first edition in which the term juvenile idiopathic arthritis is being used in the Primer on the Rheumatic Diseases. © 2008 Springer-Verlag New York.