Characterization of isolated retinal vasculitis. Analysis of a cohort from a single center and literature review

Introduction: Isolated retinal vasculitis (IRV) is an inflammatory condition of unknown etiology confined to the retinal vessels. In contrast to secondary retinal vasculitis (RV), IRV has not been well characterized.

Objective: To describe and characterize isolated forms of RV.

Methods: We performed a retrospective review (2006-2016) of IRV patients from a multidisciplinary Uveitis Unit. RV diagnosis was based on funduscopic and fluorescein angiography findings. To distinguish between secondary RV and IRV, evaluations included clinical assessment, several inflammatory, autoimmune and microbiological laboratory markers, and a chest radiography. Ophthalmological features at disease onset, therapeutic interventions, ocular relapses, visual outcomes and laboratory findings were recorded. Our cases were subsequently compared with those from a literature review.

Results: Among 192 patients with RV, 11 (5.7%) were diagnosed with IRV. Seven patients with initially presumed IRV were reclassified as secondary after further evaluation. IRV generally affected adult women. Bilateral ocular involvement and retinal phlebitis were common findings. 72% of patients presented with visual loss, which was severe in 27%. Treatments used included systemic glucocorticoids (82%), additional immunosuppressive agents (27%), intravitreal therapy (37%), panretinal photocoagulation (37%) and pars plana vitrectomy (26%). The annual relapse rate was 0.46. Although final visual acuity was considered good in 86%, 45% experienced worsening and only 27% improved.

Conclusions: IRV is a rare sight-threatening condition. Despite intensive local and systemic immunosuppressive treatment, visual improvement is observed in only 27% of cases. When IRV is suspected, a differential diagnosis excluding a systemic disease is always warranted. A multidisciplinary approach and a guided clinical, laboratory and imaging evaluation have proven to be useful to distinguish retinal single-organ vasculitis from secondary forms of RV.