Table of Contents
Ankylosing spondylitis is a chronic seronegative spondyloarthropathy which primarily involves the axial skeleton.
Risk factors
- HLA-B27 (positive in 90-95%)
- Age: peak onset 15-25 years
- Male gender
- Family history
Clinical features
Symptoms
- Low back pain
- Progressive
- Relieved by exercise
- Night pain
- Radiates to sacroiliac joints and hips
- Morning stiffness
- Systemic features: fever, weight loss, fatigue
Signs
- Question mark posture (loss of lumbar lordosis and thoracic kyphosis)
- Sacroiliac joint tenderness (sacroiliitis)
- Positive Schober’s test
- <5cm chest circumference expansion on inspiration
Extra-articular features
- Anterior uveitis
- Aortitis
- Aortic regurgitation
- AV node block
- Apical pulmonary fibrosis
- Amyloidosis → glomerulonephritis
- Achilles tendon (and other tendon) enthesitis
Investigations
- Clinical diagnosis
- X-Rays: pelvis and spine (‘bamboo spine’ is a characteristic sign caused by vertebral body fusion by marginal syndesmophytes)
- MRI: more sensitive than X-Ray
- Bloods: FBC (anaemia), ESR (raised), CRP (raised), HLA B27 (+ve)
Management
- Exercise and physiotherapy: essential
- NSAIDs (e.g. ibuprofen, naproxen, diclofenac): may need to try different ones
- TNF-α inhibitors (e.g. etanercept) may be used when NSAIDs are unsuccessful or not tolerated
- Interleukin-17A inhibitors (e.g. secukinumab): may be used in place of TNF-α inhibitors
- Other therapies: corticosteroid joint injections, short courses of corticosteroids, intravenous bisphosphonates
Reference: NICE ‘NG65: Spondyloarthritis in over 16s: diagnosis and management’ 2017
Questions
What features does the above radiograph show?
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How is Schober’s test performed?
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