SORRENTO, ITALY — The posterior uveitis known as birdshot chorioretinopathy appears to be an eye-restricted disease, reported Dr. Christian Pagnoux at the Fifth International Congress on Autoimmunity.
In a careful assessment of the largest series to date of patients with birdshot chorioretinopathy—so named because of the distinct shotgun-like scatter pattern of hypopigmented spots on the fundus—some were found to exhibit “intriguing” extraocular features, but there was no convincing evidence of systemic involvement, said Dr. Pagnoux of Cochin Hospital, Paris.
Previous studies of birdshot chorioretinopathy, in which patients complain of floaters, blurred vision, nyctalopia, and photophobia, have not addressed the possibility of patients having extraocular manifestations despite the likelihood that the disorder is autoimmune in nature.
The evidence suggesting that birdshot chorioretinopathy is an autoimmune disorder includes a strong association with the human leukocyte antigen (HLA)-A*29 gene. Moreover, clinical features of the disease resemble autoimmune S-antigen-induced uveoretinitis, and some patients have granulomatous histology findings and features associated with vasculitis, according to Dr. Pagnoux. “However, if it indeed is an autoimmune disease, it would be one of the rare—and possibly the only—autoimmune disease that is restricted to one organ,” he said in an interview.
A longitudinal cohort study initiated by ophthalmologists at Cochin Hospital, which is the French National Reference Center for Vasculitides, provided the opportunity for Dr. Pagnoux and his colleagues from the French Vasculitis Study Group to investigate disease manifestations in 118 patients.
Mean age was 51 years, and there was a slight male predominance. Each patient underwent a 30-minute medical interview using a standardized report form, and data on medical history before and after the onset of birdshot chorioretinopathy were collected.
Among the study findings were that 16% had drug allergies, 9% had asthma, 8% had diabetes, and 10% had thyroid disease. One patient had antiphospholipid syndrome, three had Raynaud's phenomenon, and five reported a history of psoriasis. In addition, 27% were hypertensive, and 14% had sinusitis. Hearing loss was reported by 7%. At the time of disease onset, 19% of patients also reported arthralgias, but none had arthritis or synovitis, Dr. Pagnoux said.
The incidence of these maladies is quite similar to those reported by the French general population, he said. “We also did not find any manifestations suggesting inflammation outside the eyes, such as elevated C-reactive protein levels. “I think one could say today, with a certain degree of confidence, that birdshot chorioretinopathy is indeed an eye-restricted disease,” he said.
Nonetheless, certain findings such as hearing loss, hypertension, and psoriasis are of interest and merit further attention as potential extraocular disease manifestations. Study limitations include the non-population control design and the potential for recall bias. However, the use of standardized report forms by physicians specializing in vasculitis may counterbalance these potential drawbacks, he said.
The study is ongoing, and patients will be re-evaluated every 5 years with the goal of providing a clearer picture of the natural history of the disease, particularly when macular edema occurs and visual acuity is lost.
Multiple distinctive hypopigmented lesions shown clustered around the optic disk: Retinal depigmentation reveals veins on transparency, and slight edema is visible. Courtesy Dr. Pr Brézin/Cochin Hospital/Paris