Overview

• Seronegative spondyloarthropathy and a chronic inflammatory disease of the axial skeleton that leads to partial or complete fusion and rigidity of the spine
• M>F (3:1), age 15-40 years old ⇒ typically young males
• Genetic Predisposition → 90-95% of patients are HLA-B27 positive
• Amboss Overview

Making Diagnosis

Clinical Features:

• Inflammatory Back Pain → early morning back stiffness, gets better with activity. May experience night pain. Insidious onset of dull pain that progresses slowly.
• Iritis/Anterior Uveitis → eye pain, redness, photophobia
• Enthesitis → inflammation where tendon or ligament attaches to bone (achilles is most common site)
• Tenderness at Sacroiliac Joint
• Reduced Spinal Mobility
• Extra-Articular Features (5 A’s) → apical lung fibrosis, amyloidosis, anterior uveitis, achilles tendinitis, aortic regurgitation
• Constitutional Symptoms → fatigue, weakness, fever, weight loss

Investigations:

• Pelvic X-Ray → requested in all patients presenting with inflammatory back pain. Shows sacroiliitis (subchondral erosions and sclerosis).
  • Lumbar X-Ray ⇒ syndesmophytes (ossification of outer fibres of annulus fibrosus) form between adjacent vertebrae causing bamboo spine. Also get squaring of lumbar vertebrae.