Título

OPTIC DISC EDEMA AND VISUAL LOSS FROM PARACENTRAL ACUTE MIDDLE MACULOPATHY MIMICKING OPTIC NEURITIS

Objetivo

To describe a case of sudden visual loss, with relative afferent pupillary defect(RAPD) and optic disc edema (ODE) associated with paracentral acute middle maculopathy (PAMM), that caused confusion with acute optic neuritis.

Relato do Caso

A 32-year-old woman was referred to our service with a suspicion of right optic neuritis. Three weeks ago, she had recurrent episodes of painless transient visual loss (TVL) in the right eye (OD) for 3 days. In the fourth day, she woke up with persistent blurred vision and mild ocular pain. She only had a previous history of migraine. At this moment, she did an eye exam that reported mild ODE with small optic disc hemorrhages and venous congestion. Best-corrected visual acuity (BCVA) was 20/40 in OD and 20/20 in the left eye and there was a discrete right RAPD. When she came to our hospital, she claimed some visual improvement, but a remaining dark spot in the central area. The BCVA was 20/20 in both eyes, still with a mild right RAPD. The ocular anterior segment was innocent and fundus examination kept the same features previously described in OD, now with a subtle abnormality in this macula. Visual field test showed a relative paracentral scotoma in OD. Cranial and orbital MRI were normal as well as cerebrospinal fluid. Fluorescein angiography was unremarkable. OCT b-scan of the macula revealed a hyperreflective band in the inner nuclear layer in OD compatible with PAMM. Further clinical and hematologic investigation was unrevealing.

Conclusão

Although some initial features suggested optic neuritis, the clinical and fundoscopic findings pointed to another etiology and OCT was essential to define PAMM. The exact mechanism for its development remains unclear, but we believe that our case was most likely due to impending central retinal vein occlusion. This case shows a possible confusion between optic neuritis and vascular retinal disease, highlighting the value of careful evaluation to determine the correct diagnosis of acute visual loss in young patients, avoiding unnecessary testing and treatment.