Ankylosing Spondylitis — SCE Rheumatology MCQ

Correct answer: E — Grade 2–4 sacroiliitis bilaterally or grade 3–4 unilaterally

The correct answer is E. The modified New York radiographic criterion is sacroiliitis of at least grade 2 bilaterally or grade 3–4 unilaterally. This patient's bilateral grade 3 changes therefore satisfy the criterion for radiographic axial spondyloarthritis (ankylosing spondylitis). Complete bilateral ankylosis is grade 4 but is not required, so A is too restrictive. HLA-B27 positivity increases the likelihood of axial spondyloarthritis but cannot make radiographic changes of any grade satisfy the modified New York threshold, excluding C. Modern diagnostic pathways can identify non-radiographic axial spondyloarthritis using MRI and clinical features, but the modified New York radiographic criterion remains explicit, excluding D. Unilateral grade 1 change is merely suspicious and is insufficient, excluding E.

Reference: National Institute for Health and Care Excellence. Spondyloarthritis in over 16s: diagnosis and management (NG65), recommendations 1.2.4–1.2.6. Published 2017; last reviewed 4 March 2025. https://www.nice.org.uk/guidance/NG65/chapter/Recommendations