| Birdshot chorioretinopathy | |
|---|---|
| Classification and external resources | |
| ICD-10 | H30.9 |
| ICD-9 | 363.20 |
| OMIM | 605808 |
| DiseasesDB | 32404 |
Birdshot chorioretinopathy, also called birdshot retinochoroidopathy, is a rare form of bilateral posterior uveitis affecting the eye. It causes severe, progressive inflammation of both the choroid and retina.
Affected individuals are usually diagnosed around age 45, a common age of onset.[1]
Contents |
Birdshot chorioretinopathy is a rare form of posterior uveitis and accounts for 1-3% of uveitis cases in general. Birdshot chorioretinopathy is thought to be an autoimmune disease. The disease has strong association with the Human leukocyte antigen haplotype (HLA)-A29, which is the strongest association between a disease and HLA class I documented (85 to 97.5% of patients are HLA-A29 positive). This indicates a role for T-lymphocytes in the pathogenesis. The disease affects typically middle aged or elderly, white caucasians. HLA-A29 is less prevalent in Asia and no birdshot chorioretinopathy cases have been reported in Asia. When birdshot chorioretinopathy is suspected, a person is usually tested to determine if they are HLA-A29 positive. However, HLA-A29 testing is not considered vital for definitive diagnosis. Since HLA-A29 is also common in the general healthy population (7%), additional (genetic or environmental) or unknown factors may be associated with HLA-A29 in the pathogenesis of BSCR.
Symptoms of this disorder include: abundant floaters, uveitis, chorioretinitis, retinitis, papillitis, retinal vasculitis, vitreous inflammation, macular edema, "flashing" lights in eyes, nyctalopia, loss of color vision, and small light-colored spots on the retina. Complete loss of visual acuity is the common prognosis.
The name of the condition comes from the small light-colored fundus spots on the retina, scattered in a pattern like birdshot from a shotgun, but these spots might not be present in early stages.
Birdshot chorioretinopathy is quite resistant to treatment.[2] Immunosuppressant therapy with corticosteroid-sparing drugs has been somewhat effective in slowing down the progressive inflammation associated with the disorder, preserving visual intregrity as much as possible. Long-term use of such medications must be closely monitored, however, due to the discomforting, and potentially debilitating and life-threatening side-effects.[2][3]
Recently, the therapeutic monoclonal antibody daclizumab has proven to be a quite effective treatment option for birdshot chorioretinopathy. Substantial reduction, and even stabilization of both vitreous inflammation and retinal vasculitis has been evident via electroretinography, during daclizumab therapy. Loss of visual acuity unrelated to the inflammation caused by the disorder, however, often remains unchanged despite usage of the drug. Contraindications and adverse side-effects are always a factor, as well.[4] Daclizumab was discontinued by Hoffman La Roche on Sept 01, 2009, and is no longer available to the US market. Hoffman La Roche letter to healthcare professionals: http://www.fda.gov/downloads/Drugs/DrugSafety/DrugShortages/UCM194907.pdf