Take-home message: Ophthalmologists should suspect autoimmune retinopathy if a patient presents with an unexplained visual loss.
Miami - Autoimmune retinopathy may not be that common, but clinicians should keep the diagnosis in mind when a patient presents with unexplained visual loss, reported Byron L. Lam, MD.
Autoimmune retinopathy is broken down into three different categories:
- paraneoplastic retinopathy, which includes recoverin-associated retinopathy and melanoma-associated retinopathy;
- non-paraneoplastic autoimmune retinopathy;
- combined paraneoplastic optic neuropathy and retinopathy.
An example of the latter category includes IgG against collapsing response-mediator protein (CRMP-5).
“There are many other yet undefined causes we don’t know about yet,” said Dr. Lam, holder of the Robert Z. and Nancy J. Greene Chair in Ophthalmology, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami.
Dr. Lam outlined the various triggers for autoimmune retinopathy, including cancer and autoimmune causes. With cancer, a cross-reaction between the retinal protein and cancer antigen may occur, leading to anti-retinal antibodies. That leads to autoimmune retinopathy, which often manifests as retinal atrophy, retinal pigment epithelium changes, and optic nerve atrophy.
When there is a non-paraneoplastic autoimmune trigger, a potential mechanism may be a cross-reaction between the retinal protein and viral or bacterial protein, leading again to anti-retinal antibodies and autoimmune retinopathy. In addition, retina degeneration, itself from other causes, may lead to an immune reaction to retinal proteins and secondary anti-retinal antibodies.
Beware of symptoms
Some symptoms of autoimmune retinopathy include subacute painless visual loss. The visual loss is associated with scotomas, photopsias, nyctalopia, dyscrhomatopsia, and photoaversion, Dr. Lam said.