Bleb-related endophthalmitis
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Sara Mehrsefat, M.D. [2]
Overview
Bleb-related endophthalmitis (BRE) is the second most frequent cause of postoperative endophthalmitis after acute and chronic post-cataract surgery endophthalmitis.
Historical Perspective
Classification
Depending on the timing of presentation and duration, bleb-related endophthalmitis (BAE) can be classified into:
- Early onset (Less than 6weeks since surgery)
- Late onset (more than 6wkeeks since surgery)
Pathophysiology
Trabeculectomy is performed to achieve very low intraocular pressure (IOP) in glaucoma eye that has failed medical management. Filtering bleb is a surgically created defect in the sclera which allows excess aqueous humor to leak out of the anterior chamber and be absorbed into the systemic circulation. There is a serious concern for bleb-related endophthalmitis (BRE) even after successful trabeculectomy.
It is thought that bleb related infections begin secondary to bleb leakage. Bleb leakage allows organism from the tear film to colonise the bleb and invade the anterior chamber or the vitreous even in a late postoperative period.
Antifibrotic agents, such as mitomycin C(MMC) and 5-fluorouracil (5-FU), are used to prevent fibrosis and scarring of the scleral flap and bleb in order to promote long-term patency. It is thought that the use of antfibrotic agents may result in bleb leakage and subsequent bleb-related endophthalmitis (BRE). Nucleic acid metabolic inhibition by the antifibrotic agents may caused bleb leakage and subsequent intraocualr infection through following mechanism:
- Reduce mucin production (secondry to loss of gablet cell)
- General conjunctival thinning
- Reduced cellularity
- Avascular bleb
Causes
- Early onset BAE
- Late onset BAE
- Streptococcus species (31%)
- Staphylococcus species (7%-22%)
- Gram negatives bacteria such as (Haemophilus influenzae 23%, Enterococcus 7%, Pseudomonas 7%)
Epidemiology and Demographics
The incidence of bleb-related endophthalmitis is approximately range from 200 to 1300 per 100,000 individuals with . It's incidence is reported to be between 0.2% to 1.3%,2,3 and is more common with the use of antiproliferative agent (up to 3%) and even higher when the bleb is placed inferiorly (up to 9.4%). Many studies have shown a higher prevalence of blebitis in younger, male, and black patients.
A single-center retrospective review from the 1990s showed that the 5 year risk of blebitis and that of BAE is 6.3% and 7.5%, respectively.
Risk Factors
- Late onset bleb leakage (increase the risk of bleb infection 26 fold)
- Inappropriate use of of The antifibrotic agents (such as 5-fluorouracil (5-FU) and Mitomycn-C (MMC))
- Reduce mucin production (secondry to loss of gablet cell)
- General conjunctival thinning
- Reduced cellularity
- Avascular bleb
- Epithelial irregularities, basement membrane breaks, and hypocellularity
- Inappropriate use of of The antifibrotic agents (such as 5-fluorouracil (5-FU) and Mitomycn-C (MMC))
- Inferior and nasal placement of bleb
- Conjunctivitis,
- Upper respiratory infection,
- Blepharitis
- Diabetes
- Trabeculectomy alone compared to combined procedure
- Chronic antibiotic use
- Trabeculectomy without concurrent cataract extraction,
- Early complications (such as early wound leak, choroidal hemorrhage, and a flat chamber)
- Juvenile glaucoma
- Nsolacrimal duct obstruction,
- Contact lens wear
- Bleb revision surgery
- Epinephrine drops
Screening
Natural History, Complications, and Prognosis
Natural History
Complications
Prognosis
Bleb-related endophthalmitis is associated with a poor prognosis. 5/200 visual acuity achieves on half of the patients who developed bleb-related endophthalmitis.
Diagnosis
Diagnostic Criteria
History and Symptoms
=Symptoms
- Ocular pain and discomfort
- Redness
- Blurred vision
Eyebrow ache Headache, External ocular inflammation
Physical Examination
Eye examination
- Whitened bleb surrounded by intense conjunctival injection
- A mucopurulent infiltrate,
- Precipitates similar to keratic precipitates
- Hypopyon within the bleb (often avascular with thin walls)
- Anterior chamber reaction and/or a hypopyon, depending on the duration of the blebitis. Frequently, there is a
- Bleb leak and consequent hypotony
Laboratory Findings
Imaging Findings
X Ray
CT
MRI
Ultrasound
Other Imaging Findings
Other Diagnostic Studies
Treatment
Medical Therapy
Surgery
Prevention
Primary Prevention
- Assessment of bleb leakage following tabeculectomy surgery in every vist
- Aggressive treatment of blebitis
- Bleb revision with conjunctival advancement to manage avascular leaking blebs (100% success rate)
- Amiotic membrane grafting as a possible alternative to conjunctival advancement (45% success rate)
Secondary prevention
- Bleb revision with conjunctival advancement to manage avascular leaking blebs (100% success rate)
- Amiotic membrane grafting as a possible alternative to conjunctival advancement (45% success rate)