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Suspected axial spondyloarthritis — SCE Rheumatology MCQ

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ModerateMusculoskeletalSuspected axial spondyloarthritisSCE Rheumatology

A 31-year-old woman is assessed for an 18-month history of low-back and alternating buttock pain. The pain wakes her during the second half of the night, improves with exercise and responds substantially to naproxen. She has had one ophthalmologist-confirmed episode of acute anterior uveitis. Examination shows reduced lumbar flexion but no neurological deficit. HLA-B27 is negative, and CRP and ESR are normal. A plain radiograph shows no definite sacroiliitis. Before referral, she underwent MRI comprising routine sagittal lumbar-spine sequences and axial T2-weighted images through the sacroiliac joints; this was reported as showing no inflammatory abnormality. The images did not include coronal-oblique T1-weighted and STIR sequences through the sacroiliac joints or STIR imaging of the whole spine. Clinical suspicion of axial spondyloarthritis remains high. Which imaging strategy is most appropriate next?

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Correct answer: E — Unenhanced MRI using an inflammatory back-pain protocol with T1-weighted and STIR sequences of the whole spine and sacroiliac joints

The previous MRI does not constitute the NICE inflammatory back-pain protocol and therefore cannot reliably exclude imaging evidence of axial spondyloarthritis. Her inflammatory back-pain phenotype and previous acute anterior uveitis maintain a high pre-test probability despite normal inflammatory markers and negative HLA-B27, neither of which excludes the diagnosis. Following a non-diagnostic radiograph, she should undergo unenhanced MRI with sagittal T1-weighted and STIR sequences of the whole spine and coronal-oblique T1-weighted and STIR sequences through the sacroiliac joints. Contrast enhancement is not routinely required to identify active inflammatory lesions and an examination confined to the sacroiliac joints would still omit the specified whole-spine sequences. CT depicts structural lesions well but involves ionising radiation and is not the recommended next investigation when an appropriate diagnostic MRI has not yet been performed. Waiting for repeat radiography risks further diagnostic delay and may miss non-radiographic axial spondyloarthritis. Bone scintigraphy is insufficiently specific for sacroiliitis and NICE advises against its use in suspected axial spondyloarthritis. If a correctly performed MRI remains non-diagnostic but suspicion is high, specialist musculoskeletal radiology review and, where appropriate, follow-up MRI should be considered.

Reference: Spondyloarthritis in over 16s: diagnosis and management (NG65) — Recommendations (Published 28 February 2017; last updated 2 June 2017; reviewed 4 March 2025) — https://www.nice.org.uk/guidance/ng65/chapter/Recommendations