Ankylosing spondylitis is a chronic inflammatory disease that primarily affects the axial skeleton, with sacroilitis being the main feature. It is one of the spondyloarthropathies.
It affects more males than females (5:1)
There is a strong association with HLA B27 (around 95% of patients)
Classic presentation:
- Low back pain
- Worse in morning
- Worse after rest
- Improves with activity
Examination
- Restricted flexion and extension of lumbar spine
- Schober’s test: 2 marks on patient’s back 10cm apart, with lower mark at level of posterior superior iliac spine normal flexion results in an increase of 5cm or more
- Loss of lumbar lordosis
- Increased thoracic kyphosis
- Decreased chest expansion
Investigation
- Spinal XR
- Squaring of vertebral bodies
- Ossification of spinal ligaments
- Fusion of vertebral column - ‘bamboo spine’
- MRI
Extra-articular associations:
- Psoriasis
- Uveitis
- Inflammatory bowel disease
- Increased risk of cardiovascular disease
- Increased risk of osteoporosis
- Aortic regurgitation
- Pulmonary fibrosis
- Cardiac conduction problems
Treatment
- Regular exercise
- NSAIDs
- Anti-TNF therapy
- No evidence for DMARDs in axial disease, but sulfasalazine may be considered for peripheral arthritis
References
Siper, J. et al. Ankylosing spondylitis: an overview. Ann Rheum Dis. 2002. 61(Suppl 3): iii8-iii18.
Ward, M. and Kuzis, S. Ceiling effects and the Schober test. J Rheumatol. 2003; 30(12): 2732-2733.
Ward, M. and Kuzis, S. Ceiling effects and the Schober test. J Rheumatol. 2003; 30(12): 2732-2733.
