ARPE – acute retinal pigment epitheliitis as a rare inflammatory disorder of the retina

Introduction
Acute retinal pigment epitheliitis (ARPE) is an inflammatory disorder of the retina. It is a self-limiting disease that often resolves spontaneously, typically with good visual recovery. The exact etiology and pathogenesis of ARPE remain unknown. The literature includes reported cases of ARPE associated with an episode of Coxsackie A virus infection, coronavirus disease 2019 (COVID-19), bisphosphonate therapy, and vaccination against COVID-19. Most commonly, ARPE affects only one eye.

Case description
A 36-year-old male patient presented to the ophthalmological emergency department with near-total vision loss in the left eye. Visual acuity testing showed 0.5/50 in the left eye and 5/5 in the right, with intraocular pressure within normal limits. The patient denied any history of trauma or chronic ophthalmological conditions. He had been suffering for depression for four years, and following a depressive episode a month ago vortioxetine was added to his therapy. Laboratory tests revealed elevated D-dimer levels and IgM antibodies against herpes simplex virus, with no IgG detected. Optical coherence tomography (OCT) and fluorescein angiography identified focal hyperreflective bands extending from the retinal pigment epithelium into the outer retinal layers and photoreceptor loss. A diagnosis of ARPE in the left eye was established. The patient was treated with systemic and local anti-inflammatory therapy, including intravenous methylprednisolone and oral acyclovir. Visual acuity in the left eye improved to 5/16.

Conclusions
Compared to other macular diseases or central chorioretinitis, ARPE has a good prognosis. For optimal patient management and comfort, an accurate diagnosis is crucial. Fundoscopy, OCT, and fluorescent angiography are essential.