Ankylosing spondylitis

Ankylosing spondylitis is a HLA-B27 associated spondyloarthropathy. It typically presents in males (sex ratio 5:1) aged 20-30 years old.

Features:

Young man with lower back pain and stiffness of insidious onset
Stiffness usually worse in the morning and improves with exercise
The patient may experience pain at night which improves on getting up

Clinical examination

Reduced lateral flexion
Reduced forward flexion - Schober's test - a line drawn 10cm above and 5cm below the back dimples (dimples of Venus). The distance between the two lines should increase by more than 5cm when the patient bends as far forward as possible
Reduced chest expansion


Other features

Apical fibrosis
Anterior uveitis
Aortic regurgitation
Achilles tendonitis
AV node block
Amyloidosis
Cauda equina syndrome
Peripheral arthritis (25%, more common if female)