Ankylosing spondylitis Flashcards
What conditions belong to seronegative spondyloarthropathies?
- ankylosing spondylitis
- psoriatic arthritis
- Reiter’s syndrome (including reactive arthritis)
- enteropathic arthritis (associated with IBD)
Features of seronegative spondyloarthropathies
- associated with HLA-B27
- rheumatoid factor negative - hence ‘seronegative’
- peripheral arthritis, usually asymmetrical
- sacroiliitis
- enthesopathy: e.g. Achilles tendonitis, plantar fasciitis
- extra-articular manifestations: uveitis, pulmonary fibrosis (upper zone), amyloidosis, aortic regurgitation
Demographics in ankylosing spondylitis
Ankylosing spondylitis is a HLA-B27 associated spondyloarthropathy.
It typically presents in males (sex ratio 3:1) aged 20-30 years old
Presentation of ankylosing spondylitis
- typically a young man who presents with lower back pain and stiffness of insidious onset
- stiffness is usually worse in the morning and improves with exercise
- the patient may experience pain at night which improves on getting up
Clinical examination in ankylosing spondylitis
- reduced lateral flexion
- reduced forward flexion - Schober’s test
- reduced chest expansion
How to perform Schober’s test?
- A line is drawn 10 cm above and 5 cm below the back dimples (dimples of Venus)
- The distance between the two lines should increase by more than 5 cm when the patient bends as far forward as possible
Other (the A’s) features of ankylosing spondylitis
the ‘A’s
- Apical fibrosis
- Anterior uveitis
- Aortic regurgitation
- Achilles tendonitis
- AV node block
- Amyloidosis
- and cauda equina syndrome
- peripheral arthritis (25%, more common if female)
Blood tests in Ix for ankylosing spondylitis
- Inflammatory markers (ESR, CRP) → typically raised although normal levels do not exclude ankylosing spondylitis
- HLA-B27→ is of little use in making the diagnosis as it is positive in:
- 90% of patients with ankylosing spondylitis
- 10% of normal patients
The imaging part of Ix of Ankylosing Spondylitis
- X- Ray → of the sacroiliac joints
- MRI → if the x-ray is negative for sacroiliac joint involvement in ankylosing spondylitis but suspicion for AS remains high
Signs of early inflammation involving sacroiliac joints (bone marrow oedema) confirm the diagnosis of AS and prompt further treatment
What one other than bloods and imaging Ix may be considered in diagnosis of AS?
Spirometry → may show a restrictive defect due to a combination of pulmonary fibrosis, kyphosis and ankylosis of the costovertebral joints.
Management of Ankylosing Spondylitis
- encourage regular exercise such as swimming
- NSAIDs are the first-line treatment
- physiotherapy
- DMARDs (such as for rheumatoid arthritis e.g. sulphasalazine) → only really useful if there is peripheral joint involvement
- Anti-TNF therapy should be given to patients with persistently high disease activity despite conventional treatments
What’s that?
- bamboo spine with a single central radiodense line related to ossification of supraspinous and interspinous ligaments which is called dagger sign
- ankylosing is detectable in both sacroiliac joints
What’s that?
Ankylosing spondylitis with well-formed syndesmophytes
What’s that?
Syndesmophytes and squaring of vertebral bodies
- Squaring of anterior vertebral margins is due to osteitis of anterior corners
- Syndesmophytes are due to ossification of outer fibers of annulus fibrosus
What’s that?
Fusion of bilateral sacroiliac joints
Sacroiliitis may present as sclerosis of joint margins which can be asymmetrical at early stage of disease, but is bilateral and symmetrical in late disease
Features of inflammatory back pain
- Morning stiffness
- Insidious onset low back pain
- onset at early age (<45 years)
- Pain improves with activity
- Can cause night pain with early morning wakening
- Pain drifts about spine (alternating buttock pain)
- Good response to non steroidal antiinflammatory drugs (NSAIDs)
Articular manifestations of AS
- Stiffness of the spine and kyphosis → a stooped posture characteristic of ankylosing spondylitis at advanced stages
- Sacroiliitis → tenderness of the sacroiliac joints (elicited by either direct pressure or indirect compression)
- Spondylitis → limited range of spine motion.
- Deformity of the spine → loss of lumbar lordosis and accentuated thoracic kyphosis
- Peripheral joints synovitis → hips
- Tenosynovitis
- Enthesitis
- Dactylitis
Extra-articular manifestations of AS
- anterior uveitis
- psoriasis
- IBD
Cardiac:
- aortitis of the ascending aorta may lead to distortion of the aortic ring, causing aortic valve regurgitation
- atherosclerosis is more prevalent in AS
Pulmonary:
- costovertebral and costosternal involvement causing limited chest expansion → restrictive pattern
- apical pulmonary fibrosis
GI:
Crohn’s or UC in 5-10% patients
Renal
- amyloidosis
- NSAIDs nephropathy (in patient with severe, long standing AS)
Neuro
- Atlantoaxial subluxation, may lead to cervical myelopathy
- Cauda equina may occur in patients with severe long-standing disease
Bone disease
- Osteopenia and Osteoporosis may occur in patients with long-standing spondylitis
