Objective: To investigate whether patients with idiopathic recurrent acute anterior uveitis (AAU) have enthesis alterations comparable with those in patients with spondylarthritis (SpA).
Methods: A blinded, controlled study of enthesis evident on ultrasound (US) examination was performed in 100 patients and controls classified into 5 groups, as follows: patients with confirmed SpA (group 1), patients with recurrent AAU who were positive for HLA-B27 and did not have SpA (group 2), patients with recurrent AAU who were negative for HLA-B27 and did not have SpA (group 3), patients with forms of uveitis other than those related to SpA (group 4), and healthy controls (group 5). In total, 12 enthesis locations were explored in each patient and control subject by 2 ultrasonographers who were blinded with regard to the diagnosis. A newly developed US method, the Madrid Sonography Enthesitis Index (MASEI), in which the diagnosis of SpA is determined as a cutoff score of 18 points, was used.
Results: A total of 1,200 entheses were explored by US in 100 patients and controls. The MASEI cutoff limit was met or exceeded by 81%, 55.6%, 40%, 10%, and 19% of the subjects in the 5 groups, respectively. The MASEI score was significantly higher in groups 1 and 2 than in groups 4 and 5. The differences between groups 1 and 3 were also found to be significant.
Conclusion: Our findings indicate that a high percentage of HLA-B27-positive patients with idiopathic recurrent AAU without features of SpA have enthesis lesions comparable with those seen in patients with SpA. These data suggest that patients with recurrent AAU, especially those who are HLA-B27 positive, have an abortive or incomplete form of SpA.