[Diagnosis of early spondyloarthritis].

PURPOSE: Spondyloarthritis (SpA) encompass different diseases with common characteristics, ankylosing spondylitis (AS) being the most typical. Undifferentiated SpA may evolve into AS. In France, SpA and rheumatoid arthritis could have the same prevalence. AS has a profound impact on the quality of live and function of patients as well as social and economic consequences for the society. KEY POINTS: There is a mean delay of five to eight years between onset of symptoms and diagnosis of AS. This is due to the fact that radiographic sacroiliitis is delayed. The purpose of an earlier diagnosis is emphasized by the need for a better management, the new diagnostic method including magnetic resonance imaging and ultrasonography, and by the efficacy of anti-TNF therapy. The current criteria (New-York, Amor, ESSG) are classification but not diagnostic criteria. Their sensitivity is insufficient for an early diagnosis of SpA. Several groups are studying methods to ensure an early diagnosis. The group of Berlin has proposed, for patients suffering inflammatory chronic back pain, an algorithm using clinical, radiological and biological signs with, if necessary, search of HLA-B27 and MRI of sacroiliac joints. But this system is theoretical and the group of Maastricht found it of little effectiveness. Furthermore, it does not take account patients with symptoms beginning out of the spine.
CONCLUSION: We believe that only the follow-up of cohorts constituted of patients with early SpA will enable us to improve our knowledge regarding diagnostic criteria and new tools for early diagnosis, as well as outcome, prognosis and early management of SpA and AS.