Viral Retinitis After Intravitreal Triamcinolone Injection in Patients with Predisposing Medical Comorbidities

Purpose: To review the cases of viral retinitis after intravitreal steroid administration at a single center, to estimate the incidence, and to propose risk factors for its occurrence.

Design: Retrospective, observational case series.

Methods: Seven hundred thirty-six intravitreal triamcinolone (IVTA) injections were administered in the clinic and operating room by 3 retina specialists at a single academic medical center between September 2002 and November 2008. Inclusion criteria were simply a history of 1 or more IVTA injections during the period. The overall incidence of viral retinitis after IVTA injection was calculated. Subsequently, a chart audit was performed to estimate the number of patients with immune-altering conditions who had received IVTA during the period, and the incidence within this subgroup was calculated.

Results: Viral retinitis developed after IVTA injection in 3 patients, yielding an overall incidence of 3 in 736 or 0.41%. An estimated 334 injections were administered to patients with an immune-altering condition, including diabetes. All 3 of the patients in whom viral retinitis developed after IVTA injection possessed abnormal immune systems, yielding an incidence rate of 3 in 334 or 0.90% within this subgroup.

Conclusions: Our high reported incidence for this potentially devastating complication can be attributed to multiple factors, including coexisting medical immunocompromising comorbidities, a higher dose with a longer duration of local immunosuppression in the vitreous, multiple injections, as well as previous viral retinitis. Caution with a high index of clinical suspicion and frequent follow-up is advised in patients receiving IVTA injection with potentially immune-altering conditions, even after apparent immune recovery.