Retina Today - Surgical Techniques for Managing Infectious Endophthalmitis (April 2018)

摘要

Infectious endophthalmitis is a devastating vision-threatening condition that involves inflammation of the entire globe. The most common form of infectious endophthalmitis results from direct inoculation of an organism from outside the body (ie, exogenous, as opposed to endogenous), typically following cataract surgery, intravitreal injection, or glaucoma filtering surgery. It usually presents acutely within 3 to 21 days after the procedure. AT A GLANCE • Infectious endophthalmitis is a devastating vision-threatening condition most often caused by an exogenous organism. • Despite the low incidence of endophthalmitis after intravitreal injections, the high volume of these injections makes this an increasing cause of infectious exogenous endophthalmitis. • The authors present their pearls for the surgical management of endophthalmitis. We previously reviewed 10 years of endophthalmitis cases (n = 758) seen at a tertiary referral center and found gram-positive organisms to be the causative pathogens in 80% of cases, followed by gram-negative pathogens (11%) and fungi (9%).1 Specifically, coagulase-negative staphylococci was the most common class and Staphylococcus epidermidis the most common species.1 With respect to endophthalmitis after intravitreal injections, the overall incidence rate is low (between 0.016% and 0.056%); however, the high volume of injections performed makes this an increasing cause of infectious exogenous endophthalmitis.2-6 In light of the increased use of intravitreal injections in recent years, this article reviews our approach to the surgical management of endophthalmitis, with the hope of imparting pearls for vitreoretinal surgeons. The Endophthalmitis Vitrectomy Study (EVS), published in 1995, demonstrated that immediate pars plana vitrectomy (PPV) after endophthalmitis does not lead to a statistically significant difference in visual outcomes in patients with better than light perception vision at presentation.7 Correspondingly, over the ensuing decades, PPV for treatment of post–cataract surgery endophthalmitis has decreased in use from 26% to only 10% of cases.8 ENDOPHTHALMITIS AFTER INJECTIONS Recently, we analyzed patients developing endophthalmitis after intravitreal injection with VEGF inhibitors to compare the outcomes of immediate tap and injection (TAI) of intravitreal antibiotics versus initial surgical PPV.2 Reviewing 258,357 intravitreal injections performed over a 10-year period, we identified 40 patients (0.016%) who developed acute endophthalmitis. There was no statistically significant difference in visual outcomes at 6 months between initial treatment with TAI and PPV. Our study was designed to mirror the EVS, albeit in a retrospective fashion. Despite the importance of the EVS findings, it can be argued that the EVS data may reflect the use of older, large-gauge PPV techniques and may not be applicable to the smaller-gauge microincisional vitrectomy surgery (MIVS) techniques widely performed today.9 Similarly, our retrospective study of endophthalmitis after intravitreal injection may include selection bias of more severe pathology that proceeded directly to surgical intervention. Due to these confounding variables, it may be that early MIVS for endophthalmitis can be of significant benefit at removing infectious material and vitreous debris. In selected cases, surgery may improve infection clearance and optimize visual outcomes. PREFERRED APPROACH Our preferred management for infectious endophthalmitis is to, first, as soon as possible, perform a vitreous biopsy (tap) via a short 25-gauge needle on a 3-mL or 5-mL syringe. A smaller gauge needle, such as 27-gauge or 30-gauge, can be used in an eye that has already undergone vitrectomy surgery. We typically remove a vitreous sample as large as the vitreous liquefaction will allow, up to the volume of fluid that may be subsequently injected (ie, 0.2 to 0.3 mL). This is fol