Chapter 1 Oligoarticular and Polyarticular Juvenile Idiopathic Arthritis

Abstract

Publisher Summary This chapter provides an overview of prevalence, pathogenesis, clinical manifestations, diagnostic investigations, differential diagnosis, and treatments of oligoarticular and polyarticular juvenile idiopathic arthritis (JIA). JIA is a heterogeneous group of diseases and only the subtype with IgM rheumatoid factor (RF) is thought to be the equivalent of adult rheumatoid arthritis (RA). Oligoarticular JIA is defined as arthritis in 1–4 joints during the first six months with exclusion of psoriasis or systemic JIA. JIA is divided into different subgroups with different peak incidences of age. Genetic predisposition, environmental influences, provoking infections, hormonal factors, and vulnerability in childhood are involved in the development of JIA. The pathogenesis of JIA is also influenced by psychological factors. In children with oligoarticular JIA, asymmetric swelling of large joints such as the knee, ankle, and elbow are most frequent, while in children with polyarticular JIA, symmetric involvement of the small joints of the hands and feet is more common. The treatment of children with JIA is mostly medical but physiotherapy and other non-pharmacological therapies also form a major component.