Background/Aims This is the first prospective and nationwide study aiming to provide epidemiological data relating to presentation, microbiology, management and outcome of endophthalmitis following vitrectomy.
Methods Two years of prospective and nationwide surveillance for cases of presumed infectious endophthalmitis within 6 weeks of pars plana vitrectomy was completed. The study obtained case reports via the established British Ophthalmological Surveillance Unit (BOSU) system.
Results Thirty-seven cases were reported and 28 met the diagnostic criteria for presumed infectious endophthalmitis following vitrectomy. Mean age was 61 years and 67% were male. Nineteen cases were 23/25 gauge and 9 cases were 20 gauge. Mean time from surgery to endophthalmitis was 5 days. Blurred vision (85.2%), pain (77.8%) and a hypopyon (77.8%) were the commonest presenting symptoms and signs. Seventeen cases (60.7%) had a positive culture. Culture-positive endophthalmitis, relative to culture-negative endophthalmitis, was no different with respect to time to presentation, symptoms, signs or outcome. Outcome was poor, with 29.6% of eyes being eviscerated or having no perception of light or perception of light.
Conclusions This study helps surgeons promptly identify cases of endophthalmitis following vitrectomy and informs them about the various management options currently used and the likely outcome of this devastating complication.
- Treatment Surgery
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As with any intraocular surgery, pars plana vitrectomy (PPV) carries a risk of endophthalmitis. Endophthalmitis is a devastating intraocular infection involving both the anterior and the posterior segments of the eye, requiring immediate treatment with intravitreal antibiotics. However, given the rarity of endophthalmitis following PPV, relatively little is known about case presentation, microbiology, management options and outcome for these eyes.
There is extensive information available relating to endophthalmitis following cataract surgery since this has been thoroughly investigated by prospective studies.1 ,2 However, it is possible that eyes with endophthalmitis following PPV will behave differently from eyes with endophthalmitis following cataract surgery since the indication for surgery and the surgery itself are entirely different.
There are several retrospective studies that have yielded small numbers of cases of endophthalmitis following PPV, and these have helpfully provided some information relating to the nature of endophthalmitis following PPV.3–19 These studies suggest that the outcome of endophthalmitis following vitrectomy is typically poor, although more recent studies suggest prognosis is perhaps improving. For example, a case series from 1995 demonstrated that 9 of the 10 cases with culture-positive endophthalmitis had final visual acuity (VA) of no light perception.4 A case series from 2004 found that 3 of their 6 cases had final VA of no light perception.7 More recently, a case series from 2007 found that 2 of their 8 cases had final VA of no light perception (although a total of 6 had final VA of count fingers or worse)10 and a series from 2008 found that none of their 13 cases had a final VA of no light perception (although 6 of the 11 had final VA of hand movements (HMs) or worse).12
We have recently completed a 2-year prospective and nationwide study, in association with the British Ophthalmic Surveillance Unit (BOSU), aiming to thoroughly investigate endophthalmitis following vitrectomy. BOSU provides an established infrastructure to prospectively investigate ophthalmic conditions, which, although rare, have important public health implications in the UK.
We have published separately information relating to the incidence and risk factors for endophthalmitis following PPV.20 This report aims to provide epidemiological data on the clinical presentation, microbiology, management and outcome of endophthalmitis following PPV.
Materials and methods
Two years of prospective and nationwide surveillance (1 May 2010–1 May 2012) for cases of presumed infectious endophthalmitis within 6 weeks of PPV was completed. The study obtained case reports via the established BOSU, which provides an established infrastructure to prospectively investigate ophthalmic conditions, which, although rare, have important public health implications in the UK.21
All independent UK ophthalmologists (consultants and associate specialists working in the NHS) were sent a monthly report card to report any case of presumed infectious endophthalmitis following PPV, during the surveillance period. The case definition was, “any case that was diagnosed and managed as having infectious endophthalmitis within 6 weeks of PPV, regardless of microbiology culture status”. PPV performed for dropped nuclear fragment after complicated cataract surgery, open-globe trauma, intraocular foreign body and endophthalmitis were excluded.
Reporting ophthalmologists were sent an initial questionnaire within 2 weeks that obtained information relating to preoperative clinical features (age, sex, VA, lens status, previous glaucoma surgery, PPV indication, diabetes mellitus, immunosuppression, oral steroid use, preoperative topical steroid use), operative details (surgeon grade, port gauge, number of ports sutured, intraoperative antibiotic, adjunctive procedures), operative complications (such as postoperative hypotony and wound leak), endophthalmitis clinical features (time to presentation, VA, symptoms, signs, intraocular pressure (IOP)) and initial management of endophthalmitis (vitreous biopsy, anterior chamber (AC) tap, microbiology, antibiotic delivery, revision vitrectomy, intravitreal or systemic steroid). A follow-up questionnaire was sent 6 months later to obtain information relating to subsequent procedures performed and final outcome (VA in both eyes and clinical findings). The initial and follow-up questionnaires are available as supplemental data/web-only files.
Culture-positive cases were compared with culture-negative cases to establish whether there was any difference between time to presentations (Mann–Whitney test), likelihood of symptoms or signs (χ2 test) or visual prognosis (χ2 test). With respect to visual prognosis, cases were classified into three visual prognostic groups, namely, (a) severe loss of vision (final VA perception of light or worse)/or eye eviscerated, (b) moderate loss of vision (final VA between 6/15 and HM) and (c) mild or no loss of vision (final VA 6/5 to 6/12). Comparisons were made between the culture-positive and culture-negative cases using the χ2 test to test whether culture status was related to visual prognostic group or not.
The incidence and risk factors for endophthalmitis following PPV have been published separately.20
Case demographics, surgical indication, preoperative and postoperative details
Thirty-seven cases of presumed infectious endophthalmitis occurring within 6 weeks of PPV were reported to the study group during the 2-year surveillance period (1 May 2010–1 May 2012).
Twenty-eight cases met the inclusion criteria for endophthalmitis following PPV (five cases relating to dropped nuclear fragment were excluded, three were duplicate reports and for one case no information could be obtained). The following results and discussion are based upon these 28 cases.
Information for individual cases relating to case demographics, surgical indication, preoperative and perioperative details is provided in table 1.
The mean average age was 61 years (range 1–87 years) and 67% were male. Fifteen (53.6%) were left eyes, 11 (39.3%) were right eyes and 2 (7.1%) had laterality unknown.
The indications for PPV were epiretinal membrane (eight cases, 28.6%), diabetic vitreous haemorrhage (seven cases, 25.0%), retinal detachment (six cases, 22.2%), vitreomacular traction syndrome (four cases, 14.3%), diabetic delamination (three cases, 10.7%), non-diabetic vitreous haemorrhage (two cases, 7.1%), macular hole (two cases, 7.1%), vitreous opacity (two cases, 7.1%) and other indications (two cases, 7.1%).
Twenty-two cases (78.6%) had their surgery completed by a consultant, four (14.3%) by a fellow, one (3.6%) by a registrar and one (3.6%) by a surgeon of unknown grade.
Nineteen cases (67.9%) were with 23/25 gauge ports and nine (32.1%) were 20 gauge ports. For the 20 gauge cases, 8 (88.9%) had all their ports sutured and 1 case (11.1%) had no ports sutured. For the 23/25 gauge cases, nine (47.4%) had no suture, seven (36.8%) had sutures to at least one port and for three cases (10.7%) the number of ports sutured was unknown.
All patients had subconjunctival antibiotics at the time of PPV except for one patient where no intraoperative antibiotics were recorded. In addition to subconjunctival antibiotics, one patient had additional subtenons antibiotics and one patient had additional intracameral antibiotics.
Clinical presentation of endophthalmitis and microbiology
Information for individual cases relating to clinical presentation and microbiology findings of endophthalmitis following PPV is shown in table 2.
The mean average time from PPV to diagnosis of endophthalmitis was 5 days (range 1–28 days). VA was no perception of light (2 cases, 7.4%), perception of light (10 cases, 37.0%), HMs (10 cases, 37.0%), count fingers (2 cases, 7.4%), 3/60 (1 case, 3.7%) and 6/18 (1 case, 3.7%).
Presenting symptoms included blurred vision (23 cases, 85.2%), pain (21 cases, 77.8%), increasing eye redness (15 cases, 55.6%) and lid swelling (7 cases, 25.9%). Hypopyon was typically noted (21 cases, 77.8%) and 11 (40.7%) reported an absent red reflex. A relative afferent pupillary defect was only reported in one case (3.7%). No patients presented with a retinal detachment. No patients had a clinically demonstrable wound leak or hypotony (IOP <6 mm Hg) on the first postoperative review or on the day of endophthalmitis diagnosis. IOP was reported in 21 cases, with the mean value being 19.3 mm Hg (range 8–40 mm Hg) on the day of endophthalmitis diagnosis.
Of the 28 cases, 17 cases (60.7%) had a positive culture from a vitreous cavity biopsy and/or an AC tap. Twenty-three of the twenty-eight cases had a vitreous biopsy (82.1%). The remaining five cases had a full silicone oil or gas fill in the vitreous cavity that precluded vitreous cavity biopsy. Of these 23 vitreous biopsies, 15 were culture-positive (65.2% yield). Fourteen of the twenty-eight cases had an AC tap (50.0%). Of the 14 AC taps, 5 were culture-positive (35.7% yield). For the five patients that had no vitreous biopsy, these all had an AC tap and two of these were culture-positive (40.0% yield).
Subgroup analysis comparing culture-positive endophthalmitis with culture-negative endophthalmitis found no statistically significant difference in the time to presentation (Mann–Whitney test, p=0.62), likelihood of symptoms or signs (χ2 test, p>0.05 for any symptom or sign) or visual prognosis (χ2 test, p=0.14).
Management and outcome
All patients received immediate intravitreal antibiotics. All patients also received topical antibiotics, 83.3% received systemic antibiotics, 43.5% received oral steroid, 33.3% had a revision vitrectomy, 17.4% received further intravitreal antibiotics and 12.5% had intravitreal steroid.
Final VA after at least 6 months follow-up was poor. All patients had their final VA recorded except for one patient who was too young to provide a monocular VA. Three eyes (11.1%) were eviscerated, three eyes (11.1%) had no perception of light, two eyes (7.4%) had perception of light, one eye (3.7%) could count fingers, fourteen eyes (51.9%) had VA 6/18 to 1/60 and four eyes (14.8%) could read 6/12 or better on the Snellen chart. Therefore, 29.6% of eyes were either eviscerated or had no perception of light or perception of light.
This is the first nationwide and prospective study to provide epidemiological information relating to the clinical presentation, microbiology, current management and outcome of endophthalmitis following PPV.
The European Society of Cataract and Refractive Surgeons (ESCRS) endophthalmitis following cataract surgery study provides data on 29 patients with endophthalmitis following cataract surgery.1 This study demonstrated that swollen lids, pain and an opaque vitreous are more likely to be associated with microbiology-positive endophthalmitis (20 patients) relative to microbiology-negative endophthalmitis (nine patients).1 In contrast, our study provides epidemiological data on 28 patients with endophthalmitis following PPV. We found that there was no difference in the culture-positive group (17 patients) relative to the culture-negative group (11 patients) with respect to time to presentation, likelihood of symptoms or signs or final visual prognosis.
The clinical presentation for these patients highlights that endophthalmitis following PPV typically presents acutely within the first week of surgery, and although patients following PPV often have poor initial postoperative vision they become aware of further blurred vision prior to the diagnosis of endophthalmitis at which point VA is poor.
Although the theoretical seeding of infection at the time of surgery is likely to occur in the posterior segment of the eye, an anterior segment hypopyon is the commonest sign that alerts surgeons to the diagnosis of presumed infectious endophthalmitis. Intravitreal triamcinolone is sometimes used during PPV and can result in a postoperative pseudo-hypopyon. Indeed, one of our cases clearly highlighted that triamcinolone had been used and that the culture was negative, suggesting that this was probably sterile pseudo-endophthalmitis. However, this case was included in the analysis since at presentation the case still warranted sufficient concern to justify intravitreal antibiotics and the details of the case met the study inclusion criteria. It was important to include culture-negative cases in the study since it is well accepted that convincing infectious endophthalmitis can occur despite a negative culture due to the small quantity of sample obtained for culture. Unlike the ESCRS endophthalmitis following cataract surgery study, our study did not have access to molecular biology techniques (PCR), which increased their chances of identifying a pathogen by 20%,22 but despite this our study had a similar rate of microbiology-positive cases (61% in this study vs 69% in the ESCRS study).
This study highlights the importance of performing an AC tap in endophthalmitis following PPV. Although such AC taps had a relatively low yield of a positive culture (35.7%) relative to the vitreous cavity samples (65.2%), following PPV it may not be possible to obtain an adequate vitreous cavity sample since the vitreous cavity maybe full with gas or oil. For this reason, in five cases, a vitreous cavity sample could not be obtained; however, in two of these cases, an AC tap provided a positive culture. In cases where both a vitreous cavity sample and an aqueous sample were obtained and a culture grown, the identity of the pathogen was the same in both samples. AC taps are however not without their risks, and surgeons should take care to avoid damaging the crystalline lens or causing hypotony (which could result in silicone oil coming into the AC).
No patients were noted to have hypotony (IOP <6 mm Hg) or wound leak on the first postoperative review or on the day of endophthalmitis diagnosis. It has been previously postulated that for smaller gauge (23/25 gauge) transconjunctival sutureless PPV that wound leak or hypotony may predispose to infection by allowing the ingress of bacteria to the vitreous cavity.23 This study suggests that if this is occurring then it may be occurring at a subclinical level.
The epidemiological data relating to the management of endophthalmitis following PPV demonstrates universal agreement on the need for immediate intravitreal antibiotics. All patients also received topical antibiotics. Given the relatively low-risk profile of systemic antibiotics, these are also typically prescribed, but it remains not possible to clearly demonstrate whether these do or do not confer additional benefit to intravitreal antibiotics alone. Surgeons are divided as to whether or not to give systemic or intravitreal steroids, perhaps having to balance the important need to reduce undue inflammation, while simultaneously being fearful that such steroids could allow the pathogen to flourish if adequate antimicrobial treatment had not been provided.
The prognosis of endophthalmitis following PPV is poor, with 29.6% of eyes being eviscerated or having no perception of light or perception of light. Only 14.8% had VA better than 6/12. Since retinal pathology is often bilateral, the fellow eye often has impaired VA (as shown in table 3), so endophthalmitis following PPV not only has a devastating outcome for the eye involved but also for the visual function for the patient.
In summary, this nationwide prospective study provides detailed epidemiological data relating to the presentation, microbiology, management and outcome of endophthalmitis following PPV. Surgeons can use this information to help their team promptly identify cases of endophthalmitis and if faced with this rare devastating problem to help guide their practice and inform their patients of the various management options and likely outcome.
The study group would like to thank the Fight for Sight charity for their financial support; Dr Barny Foot (and the BOSU) for facilitating the study throughout its course; Mrs Judith Belam and Mrs Melanie Hutchings (Royal Devon and Exeter Hospital NHS Foundation Trust) for administrative support. We would also like to thank the following ophthalmologists who helped provide control and validation data: Mr Kwabena Frimpong-Ansah, Mr Vasant Raman (Plymouth Royal Eye Infirmary), Mr Eddie Doyle, Mr Charlie James, Mr Mick Cole, Mr Will Sheehan (South Devon NHS Foundation Trust), Mr Steve Charles, Dr Whye-On Ho (Manchester Royal Eye Infirmary), Mr David Yorston, Mr Amer Awan (Gartnavel Hospital), Prof Rob MacLaren, Mr CK Patel, Mr Paul Rosen, Dr Emily Fletcher (Oxford Eye Hospital), Mr Luke Membrey, Mr Nick Muthiah (Maidstone Hospital), Mr Nick Price, Mr Kostas Chalioulias (Wolverhampton Hospital), Mr Ishtiyak Mahomed, Mr Gurpal Toor (Bradford Hospital), Mr Somnath Banerjee, Mr S Ganesh (University of Leicester Hospital), Mr Eric Ezra (Moorfields Eye Hospital). We would also like to thank those ophthalmologists who kindly reported cases to us.
Work relating to this project has been presented in part at the British and Eire Association of Vitreo-Retinal Surgeons (BEAVRS) annual meeting (2009, 2010, 2011, 2012), Royal College of Ophthalmologists annual congress (2010, 2011, 2012 and 2013) and at the American Society of Retinal Surgery annual meeting (2012 and 2013).
Collaborators Barny Foot; Judith Belam; Melanie Hutchings; Kwabena Frimpong-Ansah; Vasant Raman; Eddie Doyle; Charlie James; Mick Cole; Will Sheehan; Steve Charles; Whye-On Ho; David Yorston; Amer Awan; Rob MacLaren; CK Patel; Paul Rosen; Emily Fletcher; Luke Membrey; Nick Muthiah; Nick Price; Kostas Chalioulias; Ishtiyak Mahomed; Gurpal Toor; Somnath Banerjee; S Ganesh; Eric Ezra.
Contributors All of the authors have (1) made substantial contributions to the conception and design, acquisition of data, or analysis and interpretation of data; (2) drafted the article or revised it critically for important intellectual content; and (3) given final approval of the version to be published.
Funding The study group received funding from the Fight for Sight charity awarded via the Royal College of Ophthalmologists’ BOSU and from research funds from the Royal Devon and Exeter NHS Foundation Trust and Wirral University Teaching Hospital NHS Foundation Trust.
Competing interests RHLL has received sponsorships from Novartis and Allergan for attending conferences.
Ethics approval The study received ethical approval from the South West multicentre research and ethics committee.
Provenance and peer review Not commissioned; externally peer reviewed.
Data sharing statement Further data are available from the corresponding author.