Reappraisal of birdshot retinochoroiditis (BRC): a global approach

Abstract

Background: This study aimed to readjust the appraisal of birdshot retinochoroiditis (BRC) in light of a global approach, including the full array of investigational procedures.

Patients and methods: This retrospective study reviewed charts of BRC cases treated in the uveitis clinic of our center between 1995 and 2011. We identified 25 patients with BRC; of these, 19 had sufficient data for inclusion in the study. Patients were examined with a standard clinical approach for inflammatory disorders, including dual fluorescence angiography with fluorescein and indocyanine green, perimetry, and laser flare photometry, both at presentation and during follow-up. Spectral optical coherence tomography (OCT) was performed when available. Disease characteristics and evolutionary patterns were reported.

Results: Human leucocyte antigen was positive for the A29 allele in all patients. The mean age at presentation was 49.6 ± 10.0 years, the mean diagnostic delay was 21.5 ± 18 months, and the mean follow-up was 85 ± 60 months. Out of 19 patients, three presented with mutton-fat keratic precipitates (KPs), three had no depigmented lesions at presentation, and eight did not fulfill the recommended criterion of three depigmented peripapillar lesions. Cystoid macular edema (CMO) at entry was present in 8/19 cases. Perimetric anomalies were noted in all patients at presentation. In 92 % of cases, fluorescein findings included disc hyperfluorescence, retinal vasculitis of large vessels, and leakage from medium-sized and small vessels. In all patients, a (pseudo)-delay was noted in the arterio-venous circulation time (mean venous dye appearance = 42.1 ± 13.1 s), which reflected massive capillary leakage. At presentation, all patients exhibited indocyanine green angiographic signs, including hypofluorescent dark dots, vessel fuzziness, and areas of diffuse late hyperfluorescence. This allowed early diagnosis in 3/19 patients (16 %) without birdshot fundus lesions at presentation.

Conclusions: BRC is a granulomatous uveitis, and mutton-fat KPs do not exclude the disease. When BRC is suspected, indocyanine green angiography is crucial to allow early diagnosis and to monitor the evolution of choroiditis. Perimetry is an obligate investigation for diagnosis and follow-up. CMO is less frequent than stated earlier. Scores of fluorescein and indocyanine green angiographic signs indicated that choroiditis responded readily to therapy, but retinitis was relatively resistant to therapy.