How to Prevent and Manage Postoperative Endophthalmitis

Addressing offending organisms pre-op and quickly recognizing the infection post-op are key.

INGRID U. SCOTT, MD, MPH, AND HARRY W. FLYNN JR, MD

In n most cases of postoperative endophthalmitis, eyelid and ocular surface microflora have been implicated as the source of infection. The list of periocular risk factors for endophthalmitis is considerable: chronic blepharitis, active conjunctivitis, infections of the lacrimal drainage system, tear drainage obstruction, contaminated eyedrops, contact lens wear, a prosthesis in the fellow eye and active nonocular infections. These conditions may contribute to an abnormal rise in populations of ocular surface microbes or colonization of the ocular surface by atypical organisms more virulent than the normal microflora.

For the cataract surgeon, these scenarios also heighten the risk for prolonged surgery, vitreous loss and the ensuing complications, and contaminated irrigating solutions or intraocular lenses. Mechanical wound problems such as leakage or incarceration of the vitreous can facilitate entry of ocular surface microflora. Systemic issues specific to the individual having surgery may further lower resistance to infection. Chronic immunosuppressive therapy, diabetes mellitus and older age have also been associated with increased rates of postoperative endophthalmitis.¹

A Multi-factorial Approach

To potentially reduce the incidence of postoperative endophthalmitis, you need to address each of the factors implicated in the pathogenesis. First, attempt to decrease or eliminate eyelid and conjunctival microflora both preoperatively and intraoperatively. A topical antiseptic agent such as povidone-iodine is indicated for this use. The role of topical antibiotics and intracameral antibiotics, however, is controversial.

Administering subconjunctival antibiotic at the time of surgery was common during the era of extracapsular cataract extraction, but is less common today in the clear corneal incision phacoemulsification era. Povidone-iodine has been shown to decrease the rates of postoperative endophthalmitis, a recent review of prophylaxis for endophthalmitis following intravitreal injection concluded. Povidone-iodine has the advantages of low cost, broad-spectrum activity, widespread availability and fast bactericidal rate, but without the issues of promoting antibacterial resistance. Available data suggest topical antibiotics may not translate into a decreased rate of postprocedure endophthalmitis and, worse, may be associated with increased antibiotic resistance of ocular surface flora.²

Patient with endophthalmitis three days post-procedure. Examination demonstrated conjunctival congestion, corneal edema, hypopyon, and fibrin in the pupil.

Controversy Over Antibiotics

Administering antibiotics in the irrigating fluid for cataract surgery has become an increasingly common technique for infection prophylaxis. While the true value of this approach is uncertain, this technique carries the risks of antibiotic toxicity, toxic anterior segment syndrome (TASS), additional cost and possible bacterial resistance.

One study showed a higher risk of postoperative cystoid macular edema with prophylactic instillation of vancomycin in irrigating fluid.³ Further, at least 10 patients in the Endophthalmitis Vitrectomy Study (EVS) developed endophthalmitis in spite of receiving antibiotics in the irrigating fluid for cataract surgery. A more recent study from the European Society of Cataract and Refractive Surgeons reported 20 cases of postoperative endophthalmitis in a study group of 16,603 patients who had cataract surgery.⁴ In this study, absence of intracameral cefuroxime was associated with almost a fivefold increase in the risk of postoperative endophthalmitis.⁴

The American Academy of Ophthalmology Preferred Practice Pattern “Cataract in the Adult Eye” (2011) notes that no studies have supported the efficacy of adding antibiotics in the irrigating bottle as a means of endophthalmitis prophylaxis.⁵ Additionally, compared with an intracameral bolus, antibiotic in the infusate had the theoretical disadvantage of achieving less predictable intraocular antibiotic concentration and duration.⁵

Proper Prep and Closure

A thorough surgical prep of the lid margins, lashes and conjunctiva is recommended for intraocular surgery. Instilling 5% povidone-iodine directly on the conjunctiva followed by saline irrigation is part of a standard surgical prep. A plastic eye drape can isolate the lids and lashes from the surgical field. A dry surgical field can be maintained when instruments are passed in and out of the eye.

Attention to proper wound construction and watertight wound closure are priorities, particularly in complicated surgical procedures that tend to have a higher incidence of postoperative wound leak. Anterior vitrectomy techniques can eliminate vitreous incarceration in the wound.

When You Suspect Infection

When endophthalmitis does occur, recognition and treatment as early as possible in the disease course are important. Thus, counseling is imperative. Inform all patients who undergo intraocular procedures about the signs and symptoms of endophthalmitis — increased redness or light sensitivity, or both, eye pain and decreased vision. Instruct them to contact you immediately if such signs or symptoms appear.

The differential diagnosis of marked intraocular cellular inflammation after intraocular surgery includes sterile inflammation (for example, related to retained lens fragments, vitreous hemorrhage or TASS), iris trauma, preexisting uveitis and foreign material introduced during surgery.⁶ Retained cortical lens remnants generally cause more inflammation than nuclear remnants. These retained lens fragments may occasionally cause a marked inflammatory reaction with hypopyon, which may clinically resemble infectious endophthalmitis.⁷

Blood in the anterior chamber or vitreous cavity may look like endophthalmitis, especially when the blood is long-standing and associated with anterior segment trauma during preceding surgery. One report described hypopyon secondary to chronic vitreous hemorrhage.⁸ Moreover, difficult or prolonged surgery, which often includes vitreous loss or vitreous incarceration in the cataract incision, may increase postoperative inflammation.

In eyes with mild-to-moderate postoperative inflammation without hypopyon, therapy can begin with frequent topical corticosteroids. Careful sequential observation of such eyes will allow for appropriate diagnostic and treatment approaches. Acute-onset postoperative endophthalmitis caused by more virulent organisms, such as Streptococcus species or gram-negative bacteria, usually presents with rapidly progressive clinical signs aiding in the early diagnosis of infectious endophthalmitis. For endophthalmitis caused by the coagulase-negative Staphylococci may have fewer inflammatory signs and may have a delayed presentation, often creating difficulty in distinguishing between an infectious and a noninfectious etiology.

Treatment of Choice for Endophthalmitis

The treatment of choice for endophthalmitis is vitreous tap and injection of intravitreal antibiotics (plus/minus steroid) or pars plana vitrectomy (PPV).

One advantage of vitrectomy for infectious endophthalmitis is the ability to obtain an adequate vitreous specimen without the potentially harmful tractional effects of needle aspiration on the formed vitreous. Vitrectomy also debulks the vitreous cavity, allowing the removal of the majority of infecting organisms and other inflammatory mediators. Finally, the vitrectomized eye theoretically should allow improved drug circulation throughout the vitreous cavity.

Disadvantages of PPV include the requirement for instrumentation, possibly available only in an operating room setting, which may cause a delay in treatment. Further, fibrin and inflammatory debris on the IOL surface or in the anterior chamber can obscure one’s view of the posterior segment, making vitrectomy surgery difficult and potentially hazardous. Another disadvantage of vitrectomy is its effect on reducing the half-life of injected intravitreal antibiotics.

PPV for endophthalmitis is performed using either a two-port (vitreous cutter and infusion needle or irrigating light pipe) or three-port technique (sutured infusion cannula, endoilluminator probe and vitreous cutter), depending on the surgeon’s preference and the clinical circumstances. PPV is often recommended for endophthalmitis cases with light perception visual acuity and moderate (red reflex and poor view of fundus detail) or severe (no red reflex) vitritis. In such cases, preoperative echography can help rule out retinal detachment and document the presence or absence of a posterior vitreous detachment.

Constant Awareness Saves Vision

Postoperative endophthalmitis may cause severe visual loss. Early recognition, together with appropriate and timely treatment may reduce visual loss associated with endophthalmitis. Identifying and treating high-risk patients before intraocular surgery and maintaining careful aseptic techniques during intraocular surgery can reduce the incidence of endophthalmitis. OM

References

1. Keay L, Gower EW, Cassard SD, Tielsch JM, Schein OD. Postcataract surgery endophthalmitis in the United States. Analysis of the complete 2003 to 2004 Medicare database of cataract surgeries. Ophthalmology. 2012;119:914-922.

2. Wykoff CC, Flynn HW Jr, Rosenfeld PJ. Prophylaxis for endophthalmitis following intravitreal injection: asepsis and antibiotics. Am J Ophthalmol. 2011;152:717-719.

3. Axer-Siegel R, Stiebel-Kalish H, Rosenblatt I, et al: Cystoid macular edema after cataract surgery with intraocular vancomycin [see comment]. [Clinical Trial. Journal Article. Randomized Controlled Trial]. Ophthalmology. 1999;106:1660-1664

4. ESCRS Endophthalmitis Study Group. Prophylaxis of postoperative endophthalmitis following cataract surgery: Results of the ESCRS multicenter study and identification of risk factors. J Cataract Refract Surg. 2007;33:978-988.

5. Murphy CC, Nicholson S, Quah SA, et al. Pharmacokinetics of vancomycin following intracameral bolus injection in patients undergoing phacoemulsification cataract surgery. Br J Ophthalmol 2007;91:1350-1353.

6. Brod RD, Flynn HW Jr, Han DP, Miller D. Endophthalmitis: diagnosis, clinical findings, and management. In: Spaeth GL, Danesh-Meyer HV, Goldberg I, Kampik A, eds. Ophthalmic Surgery Principles and Practice, 4th ed. Philadelphia, Pa.; Elsevier. 2012:550-560.

7. Scott IU, Flynn HW Jr. Smiddy WE, et al: Clinical features and outcomes of pars plana vitrectomy in patients with retained lens fragments. Ophthalmology. 2003;110:1567-1572.

8. Nguyen JK, Fung AE, Flynn HW Jr, Scott IU. Hypopyon and pseudoendophthalmitis associated with chronic vitreous hemorrhage. Ophthalmic Surg Lasers Imaging. 2006;37:317-319.

Ingrid U. Scott, MD, MPH, is a retina specialist and professor of ophthalmology and public health sciences at Penn State University College of Medicine, Hershey. Harry W. Flynn Jr., MD, is also a retina specialist and professor of ophthalmology at Bascom Palmer Eye Institute, University of Miami Miller School of Medicine.