ABSTRACT
Juvenile idiopathic arthritis (JIA) is one of the most common chronic autoimmune disorders in children. It is the most common childhood rheumatic disease. Formerly known as juvenile rheumatoid arthritis (JRA) and juvenile chronic arthritis (JCA), JIA is now the widely accepted terminology. Under the new criteria, JIA consists of seven different subtypes: oligoarticular (persistent or extended), polyarticular (rheumatoid factor (RF) negative and positive), systemic, enthesitis-related, psoriatic and other (Box 63.1).1,2
JIA occurs in children with at least 6 weeks’ duration of persistent arthritis with symptom onset occurring at <16 years old. Arthritis is defined as swelling or, in the absence of swelling, limitation of motion accompanied by pain with motion, tenderness or warmth.3 JIA is diagnosed by both clinical history and examination. Onset of symptoms is often insidious and painless (relative to other types of arthritis); therefore, a high level of suspicion must be maintained in order to make the diagnosis in a timely manner. Several patients will present initially to the orthopaedist for evaluation of limp, swelling, joint contracture or joint pain. JIA is a group of highly heterogeneous disorders requiring a thorough knowledge of the signs and symptoms of the disease and the course and progression of each subtype in order to correctly make a diagnosis.
