Definition
A chronic inflammatory spondyloarthropathy affecting the axial skeleton, sacroiliac joints and entheses.
Clinical features
- Inflammatory back pain with morning stiffness
- Improved by exercise and worsened by rest
- Reduced spinal mobility
- Reduced chest expansion
- Peripheral enthesitis or arthritis in some patients
Associations
- HLA-B27
- Uveitis
- Inflammatory bowel disease
- Psoriasis in the broader spondyloarthropathy group
Examination
- Loss of lumbar lordosis
- Increased thoracic kyphosis
- Reduced Schober test
- Reduced chest expansion
- Reduced cervical rotation
Imaging
- Bilateral sacroiliitis is characteristic
- Syndesmophytes and bamboo spine in established disease
- MRI detects early inflammatory sacroiliitis
Orthopaedic relevance
- Fixed sagittal imbalance and kyphosis
- Osteoporotic spine prone to fracture
- Hip arthritis may require arthroplasty
Treatment
- Exercise and physiotherapy
- NSAIDs
- Biologic therapy where indicated
- Surgery for deformity, fracture or end-stage hip disease
Diagram
