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Rheumatology

Ankylosing Spondylitis

High EvidenceUpdated: 2026-01-01

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Red Flags

  • Cauda equina syndrome
  • Spinal fracture
  • Severe kyphosis
  • Uveitis
Overview

Ankylosing Spondylitis

1. Clinical Overview

Summary

Ankylosing spondylitis (AS) is a chronic inflammatory arthritis primarily affecting the axial skeleton. Part of the spondyloarthritis (SpA) family. Presents with inflammatory back pain (onset under 40, insidious, improves with exercise, worse at rest, morning stiffness greater than 30 minutes). Associated with HLA-B27 (90%+), uveitis, and enthesitis. Diagnosis by modified New York criteria (clinical + imaging) or ASAS criteria. Treatment includes NSAIDs, physiotherapy, and biologics (TNFi, IL-17i) for inadequate response.

Key Facts

  • Definition: Chronic axial inflammatory arthropathy
  • Demographics: Onset under 40, M:F 2-3:1
  • HLA-B27: Positive in 90%+
  • First-line: NSAIDs + physiotherapy; biologics if inadequate response

2. Clinical Features

Inflammatory Back Pain

  • Age of onset under 40
  • Insidious onset
  • Improves with exercise
  • Worse with rest
  • Morning stiffness greater than 30 minutes

Extra-Articular

  • Uveitis (25-30%)
  • Enthesitis (Achilles, plantar fascia)
  • Peripheral arthritis (30%)
  • IBD association

3. Management

Pharmacological

StepTreatment
First-lineNSAIDs (continuous)
Second-lineTNF inhibitor (adalimumab, etanercept) or IL-17i (secukinumab)

Non-Pharmacological

  • Physiotherapy (essential)
  • Exercise
  • Smoking cessation
  • Posture education

4. References
  1. van der Heijde D et al. 2016 ASAS-EULAR Recommendations for Axial SpA. Ann Rheum Dis. 2017;76(6):978-991. PMID: 28087505

Last Reviewed: 2026-01-01 | MedVellum Editorial Team

Last updated: 2026-01-01

At a Glance

EvidenceHigh
Last Updated2026-01-01

Red Flags

  • Cauda equina syndrome
  • Spinal fracture
  • Severe kyphosis
  • Uveitis

Guidelines

  • NICE Guidelines
  • BTS Guidelines
  • RCUK Guidelines