Researchers from Children’s Hospital of Philadelphia suggest that rheumatologists consider screening children with juvenile spondyloarthritis for sacroiliitis, but especially children who carry the HLA-B27 gene form of the disease with elevated C-reactive protein levels.
Prior studies have shown that one-third of children with juvenile spondyloarthritis (JspA) develop sacroiliitis within several years of diagnosis, which can be problematic on many levels. Early diagnosis and treatment can be crucial in slowing disease progression, so in this study, researchers evaluated the prevalence of sacroiliitis at diagnosis of JspA using MRI scans.
Published in the July 20, 2015 online issue of Arthritis Care and Research, the study included 40 children (mean age 14) with newly-diagnosed JspA and found 20% had active sacroiliitis and of those, 88% evidence of erosions or sclerosis; 1 (14%) had sacroiliac joint enthesitis, 2 (25%) had capsulitis, 6 (75%) had hip enthesitis, and 1 (14%) had hip arthritis.
The MRIs are especially important in diagnosis because, unlike in adults in which back pain is often the first symptom of spondyloarthritis, most children with JspA are asympomatic. Only three (38%) of eight children in the study reported having a history of back pain or tenderness in the sacroiliac joints.
This raises the issue of whether the adult definition of axial spondyloarthritis (axSpA), which requires the presence of inflammatory back pain, is less likely to apply to children, the researchers say.
“If the accuracy of examination and inflammatory back pain are poor in children, then we may be missing a significant amount of sacroiliitis and an opportunity to treat before damage occurs,” wrote the authors, who were led by Pamela Weiss, MD, of Children’s Hospital of Philadelphia.
Prior studies have demonstrated that one-third of children with JSpA develop sacroiliitis within several years of diagnosis.
While the study was limited by the small sample size, the presence of axial disease in spondyloarthritis has major implications for treatment decisions in children, “since axial disease in adults does not respond to first-line agents for peripheral arthritis such as methotrexate,” the authors wrote.
“The identification and diagnosis of those children at highest risk of subsequent progression to AS is important as early screening and/or treatment may significantly impact the disease course and other clinically important outcomes,” they conclude.
Note: Spondyloarthritis (SpA) is defined as including ankylosing spondylitis (AS), reactive arthritis, psoriatic arthritis, inflammatory bowel disease-related arthritis and undifferentiated SpA.
Weiss PF, Xiao R, Biko DM, Chauvin NA. Sacroiliitis at diagnosis of juvenile spondyloarthritis assessed by radiography, magnetic resonance imaging, and clinical examination. Arthritis Care & Research. July 20, 2015. DOI: 10.1002/acr.22665.