Rapid Review: Ankylosing Spondylitis

Reviewed January 2024

Ankylosing Spondylitis (Radiographic Axial Spondyloarthritis)

• Risk factors: male sex, age < 40
• Sx: low back pain that’s most severe at night and morning stiffness that improves with exercise
• PE: limited spinal mobility, decreased lumbar lordosis
• X-ray: squared vertebral bodies, multiple vertebral fusions (bamboo spine)
• Labs: increased ESR, positive HLA-B27
• Treatment options include NSAIDs, physical therapy, TNF-alpha blockers
• Associated with: uveitis, aortitis, IBD, psoriasis, apical pulmonary fibrosis
• Diseases associated with HLA-B27: PAIR
  • Psoriatic arthritis
  • Ankylosing spondylitis
  • Inflammatory bowel disease
  • Reactive arthritis

Sample question: A 51-year-old man presents with low back pain that has been worsening over the past several years. Radiographs of the spine demonstrate fusion of the sacroiliac joints and a “bamboo spine.” Blood tests reveal that he is human leukocyte antigen B27 positive. Which of the following findings on physical exam would be most consistent with the suspected diagnosis?