Histopathology of Streptococcus Mitis/Oralis Endophthalmitis after Intravitreal Injection with Bevacizumab

Abstract

To report the histopathologic findings of a series of patients from an outbreak of Streptococcal endophthalmitis after intravitreal injection of bevacizumab prepared by a single compounding pharmacy. Case series. Seven surgical specimens (5 enucleated globes and 2 evisceration specimens) from 7 patients with endophthalmitis after intravitreal injection of bevacizumab. Retrospective case series, including clinical data and histopathologic specimens examined by light microscopy. Review of clinical data included baseline visual acuity, clinical intervention, and time elapsed from injection to loss of globe. Histopathologic specimens were reviewed for pathologic changes at all tissue levels. Seven of 12 total patients (4 women, 3 men; mean age, 77.7 years) from an outbreak of Streptococcus mitis/oralis endophthalmitis after bevacizumab injection ultimately sustained loss of the affected globe, with an average of 139.1 days elapsed between injection and globe loss. Mean time from injection to presentation was 2.86 days (range, 1-6), and all patients were initially treated with vitreous tap and injection. Although histologic review of surgical specimens disclosed a wide range of pathologic tissue changes, recurring patterns of tissue damage were evident. All 5 enucleated globes displayed retinal detachment, fibrous proliferation with cyclitic membrane formation, rubeosis iridis, and secondary angle closure. All 7 specimens displayed persistent choroidal inflammation, in 1 case 208 days after injection. Six of 7 specimens had foci of retinal necrosis. Although vitreous cultures were positive in all cases, no organisms were identified by light microscopy in any of the 7 specimens. S.mitis/oralis endophthalmitis is a devastating complication of intravitreal injection with bevacizumab with a high rate of globe loss (7 of 12 patients, 58.3%) and a wide variety of severe pathologic tissue changes. Although no organisms were identified in the examined tissues, persistent inflammation was present in all cases, and fibrous proliferation resulted in cyclitic membrane formation and retinal detachment in all enucleated globes. These findings suggest that potential globe-salvaging interventions must address a pattern of changes involving persistent, chronic inflammation and fibrovascular proliferation as key components.