This 41YO male presented with 4 days of severe vision loss in his right eye. Vision was hand motion OD and 20/20 in his normal left eye.
Color photography shows multiple focal yellow-white deep retinal lesions with a submacular worm and overlying neurosensory detachment. OCT scanning shows a bacillary layer detachment with various cuts through the hyperreflective worm.
Direct photocoagulation of the worm was impossible due to its submacular location and continued movement. The worm subsequently died and was absorbed following a 2-week course of oral albendazole 400mg BID and steroids. Three weeks later, vision improved to 20/30. Chorioretinal scarring is noted in the region of the prior worm, and the inflammatory lesions are mostly resolved.
Learning Points:
Originally described by Gass (Ophthalmology 1978;85:521-545), diffuse unilateral subacute neuroretinitis (DUSN) is a syndrome in healthy young adults characterized by unilateral decreased vision, vitritis, and papillitis, with recurrent crops of transient gray-white outer retinal/RPE lesions. Optic atrophy, diffuse RPE changes, decreased visual field, and electroretinogram are long-term sequela in untreated cases.
DUSN is caused by at least 2 different-sized subretinal nematodes that can remain viable in the eye for up to 3 years. If identified, the extramacular worm can be treated with thermal photocoagulation, surgically removed, or treated with systemic anthelmintic therapy.
