Bleb-related infections: clinical characteristics, risk factors and outcomes in an Asian population

Session Details

Session Title: Glaucoma II

Session Date/Time: Monday 15/09/2014 | 08:00-10:30

Paper Time: 09:39

Venue: Boulevard F (Level 1)

First Author: : S.Perera SINGAPORE

Co Author(s): :    Z. Yap   Y. Chin   G. Teh   J. Ku   T. Chan   M. Nongpiur

Abstract Details

Purpose:

Our study seeks to verify the hypothesis that blebitis precedes and leads to bleb related endophthalmitis (BRE) if left untreated.

Setting:

Singapore National Eye Centre

Methods:

Patient notes were identified for review from January 1996 – July 2013. Identification was done via the center’s long standing endophthalmitis audit, glaucoma department bleb-related infection (BRI) audit and microbiology laboratory database identifying all conjunctival swabs taken from blebs.Blebitis was defined as anterior segment inflammation with mucopurulent material in or around the bleb, usually with anterior chamber cells but no hypopyon. Hypopyon or vitreous inflammation was termed BRE.

Results:

The mean age of all subjects(n=39) was 68.4 with a preponderance of men (74.4%) and Chinese (74.4%). BRE patients were approximately 9 years older than blebitis patients. Majority of subjects had POAG (n=28, 71.8%) with 18(46.2%) subjects having a co-existing eye condition. Diabetes was shown to be a prominent risk factor for BRE compared to blebitis(p=0.047).From similar pre-infective IOP levels of around 12mmHg, IOP dropped in blebitis but doubled with BRE (p=0.002). However, 2 weeks post treatment, IOPs in both groups returned to pre-infective levels. Increasing vascularity of the bleb conferred some risk towards the more severe infection(p=0.004); subjects with blebitis more often had an avascular bleb(84.6%) while those with BRE trended towards a moderately vascular bleb(42.9%). 50% of all our patients had no growth from conjunctival culture. Streptococcus species were the most frequently isolated microbe(15.4%), followed by Haemophilus influenzae(12.8%) and coagulase-negative Staphylococcus(10.2%). The distribution of causative micro-organisms between the blebitis and BRE groups was very similar, implying that no particular micro-organism has a propensity to greater pathogenicity and progression to BRE.

Conclusions:

We found diabetes to be a prominent risk factor for BRE. Uniquely our IOP results highlight the divergent courses of each disease and may reflect the added inflammatory load in BRE. The lowering of the IOP at infection with blebitis likely represents objective evidence of subclinical leaks or bleb sweating- a feature which is consistent with the avascular bleb morphology noted too. Microbiological analysis of isolates implies that blebitis and BRE have a shared infective aetiology, upon which altered immunity predisposes towards BRE.

Financial Interest:

NONE