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
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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)