Ankylosing Spondylitis: an Update

Background: Ankylosing spondylitis (AS) affects one in 200 individuals and is usually diagnosed many years after onset of symptoms. Chronic back pain is common and recognition of early disease requires clinical experience and a high index of suspicion. Further, inflammatory markers are not invariably elevated and radiographic changes are often late findings.

Objective: The objective of this review is to address AS and the recently defined disorder of non-radiographic axial spondyloarthritis. The latter is a common early presentation of AS, before the development of radiographic sacroiliitis, and will evolve into typical AS in 50% of patients.

Discussion: MRI may be particularly useful in evaluating early disease, although chronic changes of sacroiliitis are better seen on plain X-rays. Nonsteroidal anti-inflammatory drugs (NSAIDs) are first-line therapy and recent studies suggest that regular use among patients with AS slows radiographic progression. Tumour necrosis inhibitor therapy has strikingly improved quality of life for the more than two-thirds of AS patients with an inadequate response to NSAIDs.