Nr-axSpA vs AS — SCE Rheumatology MCQ

Correct answer: B — Nr-axSpA and ankylosing spondylitis lie within the same axial SpA spectrum; disease burden can be comparable, and only some patients develop radiographic sacroiliitis

Explanation lettering: C = shown as A · E = shown as B · D = shown as C · A = shown as D · B = shown as E

Nr-axSpA and ankylosing spondylitis, now commonly termed radiographic axial SpA, are phenotypes within the axial SpA spectrum, distinguished principally by whether definite structural sacroiliitis is visible on plain radiographs. Absence of radiographic change does not imply trivial disease: pain, disease activity, functional impairment and quality-of-life burden can be comparable. Some patients subsequently develop radiographic sacroiliitis, but progression is neither inevitable nor readily predictable. Therefore C and D are incorrect. Nr-axSpA can require active treatment, so A is false. It is not an unrelated disease process, excluding B. Treatment decisions should reflect disease activity, objective inflammation, comorbidity and previous response rather than assuming severity from radiographic status alone.

Reference: National Institute for Health and Care Excellence. TNF-alpha inhibitors for treating active ankylosing spondylitis and non-radiographic axial spondyloarthritis (TA383), committee discussion sections 4.49 and 4.52, 2016. https://www.nice.org.uk/guidance/ta383/chapter/4-Committee-discussion