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Spondyloarthritis
Inflammatory back pain in a young person — starting before 40, better with activity and not with rest, waking them at night — points to HLA-B27-linked spondyloarthritis; NSAIDs are first-line, and if they fail the next step is anti-TNF or anti-IL-17, not methotrexate.
Why it matters in the exam
The classic question presents a young man with low back pain and long morning stiffness that improve with movement, sometimes with Achilles tendon inflammation or unilateral anterior uveitis. The candidate must separate inflammatory from mechanical back pain, request an X-ray or MRI of the sacroiliac joints and an HLA-B27 test, and remember the family of diseases: ankylosing spondylitis (with a "bamboo spine"), psoriatic arthritis, reactive arthritis and arthritis linked to inflammatory bowel disease.
Treatment questions test the order: exercise and full-dose NSAIDs for at least 2–4 weeks; if two NSAIDs fail — a TNF or IL-17 inhibitor. Well-known distractors: methotrexate and sulfasalazine do not work for axial disease (only for peripheral joints), and systemic steroids are not recommended for the spine. Reactive arthritis has the clue of a preceding infection — urethritis (Chlamydia) or diarrhoea — followed by arthritis, conjunctivitis and urethritis. Psoriatic arthritis shows DIP joints, a "sausage" digit and nail changes. Remember that a positive HLA-B27 alone does not make the diagnosis — it is common in the healthy population too — and a normal CRP does not exclude the disease; the diagnosis rests on the combination of history, imaging and tests.
Key points
- Inflammatory back pain: before 40, better with activity, night pain, stiffness over 30 minutes.
- HLA-B27 and sacroiliitis on MRI.
- NSAIDs first; then anti-TNF or anti-IL-17.
- Methotrexate and sulfasalazine only for peripheral joints.
- Reactive: after urethritis or diarrhoea; psoriatic: DIP and sausage digit.
Summary table
| Disease | Clues | Findings | Treatment |
|---|---|---|---|
| Ankylosing spondylitis | Young man, inflammatory back pain, uveitis | Sacroiliitis, "bamboo", reduced Schober | NSAIDs; anti-TNF or anti-IL-17 |
| Psoriatic | Psoriasis, DIP, sausage digit, nails | "Pencil-in-cup" on the film | Methotrexate for peripheral; biologic for axial and skin |
| Reactive | 1–4 weeks after urethritis or diarrhoea | Arthritis, conjunctivitis, urethritis | NSAIDs; treat Chlamydia |
| IBD-related | Crohn's or UC | Peripheral or axial arthritis | Treat the IBD; anti-TNF suits both |
| Inflammatory back pain | Onset before 40, gradual, better with activity, night pain | Morning stiffness over 30 minutes | Separate from mechanical pain |
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Sources
- ASAS-EULAR recommendations for the management of axial spondyloarthritis, 2022 — NSAIDs, TNF and IL-17 inhibitors
- ACR/SAA/SPARTAN Recommendations for the Treatment of Ankylosing Spondylitis and Nonradiographic Axial Spondyloarthritis, 2019 — First-line and biologic therapy
- Harrison's Principles of Internal Medicine, 21st edition (2022) — The Spondyloarthritides
Sources are given for further reading; the text is written afresh and not copied from them.
Reviewed by the Examqo AI Professor · 2026-11-02. The text may contain errors; when in doubt, check the source.