Juvenile Idiopathic Arthritis
Juvenile Idiopathic Arthritis (JIA) is the most common rheumatic disease of childhood. Current estimates of incidence of JIA in the U.S. range from approximately 10 – 100/100,000 children, resulting in current estimates of approximately 100,000 patients under the age of 18.
JIA is defined as persistent arthritis for more than 6 weeks with an onset at less than 16 years of age, after excluding other causes. There are three major types of JIA. Each type is based on the number of joints affected and other symptoms during the first 6 months of active disease.
Oligoarthritis – is the most common type, affecting about 40-55% of all children with JIA. In this type one to four joints are affected.
Polyarthritis – affects about 35% of children with JIA. Five or more joints are affected in this type.
Systemic JIA – affects 10-20% of children with JIA. It causes whole-body symptoms, such as fever and rash, which usually occur before joint symptoms appear. Systemic JIA (SJIA) may affect any number of joints.
In the past decade, there have been significant advances in therapy with the development of new treatments including biologic disease-modifying agents, which have resulted in significant changes in its management. Despite this, there is very little evidence upon which therapy of children with JIA can be based. The detection of irreversible effects early in JIA indicate early therapeutic intervention is preferable. The aim of drug therapy in SJIA is the effective suppression of uncontrolled systemic and local inflammation to attain disease remission and to avoid chronic disease complications.