This 31YO female presented with 1 week of decreased vision in her right eye following a febrile illness. Vision was 20/200 OD and 20/20 in her normal OS.
Color photography shows opaque, white inner and deep retinal whitening centered in the superonasal macula, with surrounding subretinal fluid extending into the temporal and inferior macula. A lipid star radiates superiorly and nasally from the foveal center. OCT scanning confirms a highly elevated serous detachment.
An extensive infectious workup was negative for common bacterial, viral, and parasitic etiologies. Given the history of antecedent fever and characteristic retinal findings, a diagnosis of post-fever (epidemic) retinitis was favored. She was treated with oral corticosteroids and doxycycline. At follow-up, visual acuity improved dramatically from 20/200 to 20/30.
Learning Points:
Epidemic (post-fever) retinitis is an infectious or para-infectious entity that develops in immunocompetent individuals several weeks following a bacterial, viral, or protozoal infection. Causes include Dengue, Rickettsiosis, West Nile, Leptospirosis, Chikungunya, Typhoid, and Ebola. Serologic workup is negative in about 60% of cases (Kawali et al, Indian J Ophthalmol 2020;68:1916-1919), due to patients often presenting when acute-phase serologies are difficult to interpret, and viremia has resolved; limitations of available serologic testing; heterogeneous and overlapping etiologies; and a potential immune-mediated response.
Patients present with sudden, painless vision loss. Fundus findings include unilateral or bilateral unifocal or multifocal patches of retinitis with possible nerve involvement, serous macular detachment, and vasculitis or frosted branch angiitis. A macular lipid star in post-fever retinitis is uncommon, found in only 3.3% of affected eyes in rickettsial retinitis (the best-studied cause).
The exact pathogenesis remains uncertain; however, a post-infectious immune-mediated mechanism has been proposed. There is usually a favorable response to steroids and treating the underlying infectious cause with appropriate systemic therapy. See Mahendradas et al (Indian J Ophthalmol 2020;68:1775-1786) for an excellent post-fever retinitis review.
