Undiagnosed spondyloarthropathy in patients presenting with anterior uveitis.

OBJECTIVE: To investigate patients with formerly undiagnosed underlying spondyloarthropathy (SpA) in a series of anterior uveitis (AU) cases and to describe the rheumatologic and ophthalmologic characteristics of these patients.
METHODS: Patients with anterior uveitis referred to the Uveitis Clinic between January 1992 and December 1998 who had a final diagnosis of SpA were included in the study group. The diagnosis of SpA was based on current diagnostic criteria. Patients were classified into 2 groups: formerly diagnosed, or undiagnosed SpA before attendance at the uveitis clinic. Demographic features, clinical symptoms, ophthalmologic characteristics, and laboratory tests were collected prospectively in each patient. A regression logistic model was applied.
RESULTS: We evaluated 514 patients with anterior uveitis; 117 (22.7%) had some type of SpA. Ankylosing spondylitis was the most frequent diagnosis (64.1%). More than half the patients (53%) were diagnosed with SpA after an episode of uveitis; the percentage was up to 90.9% in undifferentiated SpA. Clinically, the formerly diagnosed and undiagnosed groups were quite similar, inflammatory low back pain being the most frequent symptom in both groups. Radiological sacroiliitis was less common and with a lower grade in the formerly undiagnosed group. Acute recurrent unilateral anterior uveitis was the most frequent clinical pattern in the group as a whole (68.3%), observed in all subgroups, except for inflammatory bowel disease related SpA, which presented panuveitis as the most frequent pattern.
CONCLUSION: SpA was the most frequent systemic disease related to anterior uveitis, seen in more than 50% of our SpA cases diagnosed after an episode of uveitis. The undiagnosed SpA patient is generally an atypical case, with a shorter clinical evolution and less radiological damage.