Birdshot Retinochoroidopathy

 Birdshot Retinochoroidopathy

  • Rare, chronic bilateral inflammatory disorder
  • Etiology: unknown
  • 96% of patients have human leukocyte antigen (HLA) - A29, mostly sub-type 2

Clinical features:

  • Affects people in the fourth to sixth decades
  • Affects women more than men
  • Remissions and exacerbations are common
  • Symptoms: floaters, gradual painless blurring of vision, dark-light adaptation impairment and peripheral photopsia
  • Signs:
    • Mild nongranulomatous iritis
    • Vitritis
    • Disc edema
    • Vascular sheating
    • Characteristic oval, yellow-cream "birdshot" chorioretinal lesions
    • May be complicated with optic atrophy, cystoid macular edema or choroidal neovascularization
  • Electrophysiologic studies demonstrate a reduced electroretinogram (ERG) and normal or reduced eletrooculogram (EOG) responses
  • Fluorescein angiogram:
    • More placoid lesions may be seen. They remain hypofluorescent initially, but may stain in the later phases especially by the involvement of RPE.
    • Diffuse leakage of dye from the retinal vessels and cystoid retinal edema may also be appreciated.
  • ICG angiography reveals more lesions than fluorescein angiography which appear as hypofluorescent spots

Management:

  • Observation for patients with relatively mild inflammation and asymptomatic
  • Systemic steroid is indicated for more severe inflammation with decreased visual function
  • Immunosuppressive agent such as cyclosporine has shown to be helpful.
  • Note: due to the side effect of cyclosporine, patients should be monitored for hypertension, elevation of blood urea nitrogen and creatinine.