Assessment of Sacroiliitis at Diagnosis of Juvenile Spondyloarthritis by Radiography, Magnetic Resonance Imaging, and Clinical Examination

Abstract

Objective We evaluated the prevalence of sacroiliitis at diagnosis of juvenile spondyloarthritis (JSpA) and the accuracy of physical examination and back pain to detect sacroiliitis, using imaging as the reference standard. Methods We performed a prospective cross-sectional study of 40 children with newly diagnosed JSpA and 14 healthy controls. Subjects were assessed using physical examination, anteroposterior pelvic radiograph, and pelvic MRI. Differences in clinical features between those children with and without sacroiliitis were assessed by Fisher’s exact test for categorical variables and Wilcoxon rank sum test for continuous variables. Accuracy of physical examination and back pain for detection of sacroiliitis was determined using MRI as the reference standard. Predicted probability of sacroiliitis was determined using exact multivariate logistic regression. Results Eight (20%) children with JSpA had active sacroiliitis. Of those subjects with active changes on MRI, 7/8 (88%) also had evidence of erosions or sclerosis. Five (13%) children with JSpA and 1 (7%) control had non-periarticular bone marrow edema. Of the subjects with active sacroiliitis only 3 (38%) reported a history of back pain or tenderness on palpation of the sacroiliac joints. The positive and negative predictive values of clinical exam features and back pain for detection of sacroiliitis were low. The estimated probability of having sacroiliitis was 0.84 (95% CI: 0.40–1.00) in HLA-B27+ patients with an elevated CRP. Conclusion Active sacroiliitis by MRI is common at diagnosis in JSpA and is frequently asymptomatic. Children who are HLA-B27+ and have elevated CRP levels have the highest probability of sacroiliitis.

Course of patients with juvenile spondyloarthritis during 4 years of observation, juvenile part of GESPIC

“…7 8 The knowledge on the course and the outcome of jSpA from published studies is limited. [9][10][11][12][13][14][15][16][17][18][19][20][21][22] Available studies were mainly based on JIA cohorts, and therefore, the subgroup of ERA or jSpA constituted often small subgroups in these JIA cohorts. An unfavourable outcome was reported for ERA or jSpA in most of these studies.…”

Reply

“…The sensitivity and specificity for this definition of sacroiliitis for positive findings on MRI in our prospective cross-sectional study of 40 children with newly diagnosed JSpA (3) was 0.25 (IQR: 0, 0.55) and 0.53 (IQR: 0.36, 0.71). If imaging is not performed to confirm the diagnosis, the low positive predictive value of sacroiliitis using ILAR definition may lead to unnecessary treatment of children with biologics agents, assuming there is no other justification for their use.…”

“…We thank Dr. Chogle for his comments on the article by Weiss et al (3) examining the utility of the Assessment of Spondyloarthritis International Society (ASAS) criteria for Axial SpA in children with juvenile spondyloarthritis (JSpA).…”

Conventional radiography in juvenile idiopathic arthritis: Joint recommendations from the French societies for rheumatology, radiology and paediatric rheumatology

“…A radiographic view specifically designed to assess the sacro-iliac joints is not recommended, as the results are not interpretable in skeletally immature patients and radiation exposure is significant [20]. In patients with axial inflammatory pain, MRI (for both sacro-iliac and hip joints) and US (for the hip joint) may be more relevant [67]. …”