Ankylosing Spondylitis

Question 1

What is ankylosing spondylitis?

Answer 1

Ankylosing spondylitis is an inflammatory condition, affecting the axial skeleton, that causes progressive stiffness and pain

Question 2

What are the main joints affected in ankylosing spondylitis?

Answer 2

Sacro-iliac joints
Vertebral column joints

Question 3

What gene is anklylosing spondylitis linked to?

Answer 3

HLA-B27

Question 4

What is the presentation of ankylosing spondlyitis?

Answer 4

Pain and stiffness in the lower back
Sacroiliac pain (buttock region)
Stiffness is usually worse in the morning and improves with exercise

Question 5

What findings will be seen on examination in someone with ankylosing spondylitis?

Answer 5

Reduced lateral flexion of spine
Reduced forward flexion of spine
Reduced chest expansion

Question 6

What special test looks for forward flexion of the spine?

Answer 6

Schober’s test
- A line is drawn 10cm above and 5cm below the L5 vertebra - this distance should increase by 5cm as the patient leans forwards

Question 7

What conditions are associated with ankylosing spondylitis?

Answer 7

5As
- Anterior uveitis
- Aortic regurgitation
- Atrioventricular block
- Apical lung fibrosis
- Anaemia of chronic disease

Question 8

What investigations may be performed in suspected ankylosing spondylitis?

Answer 8

Inflammatory markers - CRP, ESR
HLA-B27 testing
X-ray spine and sacrum
MRI spine - can show bone marrow oedema before bone changes

Question 9

What changes are seen on XR in ankylosing spondylitis?

Answer 9

Squaring of the vertebral bodies
Subchondral sclerosis and erosions
Syndesmophytes
Ossification of the ligaments, discs and joints
Fusion of the facet, sacroiliac and costovertebral joints

Question 10

What is the management of ankylosing spondylitis?

Answer 10

First line - NSAIDs
Second line - Anti-TNF medications
Third line - secukinumab or ixekizumab (interleukin-17 monoclonal antibodies)