Outbreak of Rift Valley Fever Retinitis in Rwanda: Novel Imaging Findings and Response to Treatment with Corticosteroids

PurposeTo describe the clinical and epidemiological characteristics of the first epidemic of Rift Valley Fever retinitis in Rwanda and to report novel imaging findings and a possible role for corticosteroids.MethodsRetrospective analysis of all patients who presented with presumed Rift Valley Fever retinitis at the Rwanda Charity Eye Hospital over a period of 4 months in 2022. Multimodal images are reviewed including optical coherence tomography, fluorescein angiography, color, infrared, red-free, and autofluorescence photography.ResultsThe newly identified arciform hyporeflective pattern on infrared imaging was present in 100% of patients. Out of 9 patients treated with oral corticosteroids, 7 (78%) experienced a visual acuity increase of at least 0.2 during follow-up, in comparison to only 4 (28%) out of 14 of untreated patients. Out of four patients treated with a subtenon corticosteroid injection, only one (25%) reached this threshold. Post-hoc pairwise comparison with Bonferroni correction revealed a significant difference in average visual acuity improvement (p = 0.034) between patients receiving oral corticosteroids (0.35 & PLUSMN; 0.07) versus no treatment (0.11 & PLUSMN; 0.04).ConclusionThe identified arciform hyporeflective pattern on infrared imaging appears to be characteristic of Rift Valley Fever retinitis and should be known to clinicians working in endemic regions. Compared to a historical cohort and to untreated patients in this non-randomized study, there appears to be a benefit of treatment with oral corticosteroids. ARTICLE SUMMARY STATEMENTThis is the first reported outbreak of Rift Valley Fever retinitis in Rwanda, demonstrating a characteristic arciform peri-macular pattern on infrared imaging not previously published and a possible treatment effect of oral corticosteroids.

Automated summary

This study describes the clinical and epidemiological characteristics of the first epidemic of Rift Valley Fever retinitis in Rwanda and reports novel imaging findings as well as a possible role for corticosteroids. A retrospective analysis was conducted on all patients with presumed Rift Valley Fever retinitis at the Rwanda Charity Eye Hospital over a 4-month period in 2022. Multimodal imaging, including optical coherence tomography, fluorescein angiography, and various photography techniques, was reviewed.