Diffuse unilateral subacute neuroretinitis

Background. Diffuse unilateral subacute neuroretinitis (DUSN) is an inflammatory disorder of the retina thought to be caused by a motile worm. It initially presents with unilateral recurring crops of gray-white retinal lesions and mild to severe inflammation. Over a period of months, diffuse retinal pigment epithelium (RPE) changes, arteriolar attenuation, and optic atrophy will develop. In approximately 25% of cases, a worm is visualized during the eye examination. Laser treatment to kill the worm is the only reliable way to halt progression of this disease. Methods. The following case report presents a 9-year-old girl with unilateral vision loss. Results. Clinical observation and several blood tests to rule out systemic diseases resulted in a diagnosis of DUSN. Although a worm was not visualized, laser treatment of its suspected location resulted in recovery of some vision. Conclusions. DUSN is often diagnosed by clinical presentation alone, because a worm may not be visualized. An appropriate initial work-up and timely initiation of laser treatment are essential to preservation of vision.