The joints in juvenile idiopathic arthritis

Insights into Imaging, Apr 2015

Lil-Sofie Ording Muller, Paul Humphries, Karen Rosendahl

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The joints in juvenile idiopathic arthritis

The joints in juvenile idiopathic arthritis Lil-Sofie Ording Muller 0 3 Paul Humphries 0 1 3 Karen Rosendahl 0 3 0 Department for Radiology and Intervention, Oslo University Hospital , Oslo , Norway 1 Institute of Child Health, UCL, University College London Hospital NHS Trust and Great Ormond Street Hospital for Children , London , UK 2 Lil-Sofie Ording Muller 3 Department of Radiology, Haukeland University Hospital , Bergen , Norway Juvenile idiopathic arthritis is the most common rheumatic entity in childhood. Imaging has become an important supplement to the clinical assessment of children with JIA. Radiographs still play an important role in the workup, and long-term follow-up in children with JIA, but are not sensitive to findings in the early disease stage. Both ultrasound and MRI are more sensitive to inflammatory changes than clinical assessment alone. However, the differentiation between normal findings and pathology can be challenging, particularly in early disease. The objective of this review is to discuss the role of imaging in JIA, describe the typical findings on different modalities and highlight the challenges we face regarding the reliability and accuracy of the different methods for imaging the joints in children with JIA. Juvenile idiopathic arthritis; Magnetic resonance imaging; Ultrasound; Paediatrics; Musculoskeletal - Juvenile idiopathic arthritis (JIA) is defined as arthritis of unknown cause, with disease duration of more than 6 months, occurring in children under 16 years. It is the most common rheumatic entity in childhood with a prevalence of 0.61.9 in 1000 children. The exact pathogenesis is not fully understood but is thought to include both genetic and environmental components. JIA is not one single disease but includes a subset of different childhood arthritides (Table 1). Both clinical presentation and outcome vary with clinical subtype, and persistent oligoarthritis has been shown to have the best prognosis [13]. Despite the heterogeneity, it is likely that there is some genetic overlap, as all JIA subtypes share joint inflammation as the most prominent disease feature [14]. Joint pathogenesis involves inflammation of the synovial lining, with the potential to cause joint destruction. There is infiltration of the synovium by inflammatory cells. The lining layers of the synovium then become hyperplastic with increased vascularity. The pannus is comprised primarily of invasive cells and the synovium becomes locally invasive at the synovial interface with cartilage and bone. Subsequent Summary of the main features of the six different subtypes of JIA Early peak 24 years; late peak 911 years Four or fewer joints involved the first 6 months Four or more joints involved within the first 6 months, absence of IgM RF. Heterogeneous disease with three subsets. Prognosis varies with the disease subset Four or more joints involved within the first 6 months, IgM RF positive. Resembles adult RA. Involvement of small joints. Progressive and diffuse joint involvement Characterised by enthesitis and arthritis. Often HLA-B27 positive. Commonly hip involvement at presentation. Often a mild and remitting course but may progress with sacroiliac and spinal joint involvement, resembling ankylosing spondylitis Arthritis and psoriatic rash or psoriasis in close family. Controversial definition, resembles oligoarthritis but more often with dactylitis and involvement of both small and large joints Arthritis and quotidian fever plus one or more of the following symptoms: characteristic rash, hepatomegaly, splenomegaly, lymphadenopathy, serositis. Variable course; 58 % develop macrophage activation syndrome destruction of the bone and cartilage occurs as a result of antibody deposition and degradative enzymes [5]. It is believed that the bone destruction in JIA is a consequence of overlying cartilage degradation. The inflammation may also cause growth disturbances, both systemically and locally in the affected joint. The typical manifestations of the articular and periarticular inflammation in early and late disease are shown in Table 2. The objective of this review is to discuss the role of imaging in JIA, describe the typical findings on different modalities and highlight the challenges we face regarding the reliability and accuracy of the different methods for imaging the joints in children with JIA. The role of imaging in JIA Currently, the diagnosis of JIA is based on clinical and laboratory findings and does not include imaging. However, clinical assessment of children with joint complaints is challenging and laboratory findings are often equivocal. This has led to an increased use of imaging for both diagnosis and follow-up, particularly of joints that are frequently affected but may be asymptomatic, such as the temporomandibular joint (TMJ) [6]. Imaging is used to determine the presence and extension of joint inflammation and can more accurately distinguish between arthr (...truncated)


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Lil-Sofie Ording Muller, Paul Humphries, Karen Rosendahl. The joints in juvenile idiopathic arthritis, Insights into Imaging, 2015, pp. 275-284, Volume 6, Issue 3, DOI: 10.1007/s13244-015-0406-0