Post Injection Endophthalmitis (PIE)

From EyeWiki

Disease Entity

Post Injection endophthalmitis (PIE)

PIE is a dreaded complication and refers to specific endophthalmitis developing following the intravitreal administration of drug injections, which commonly may be anti-vascular endothelial growth factor agents (anti-VEGF agents) or corticosteroids. It is not uncommon in today's era when the use of anti-VEGF drugs is wide-spread and a very commonly performed out-patient procedure in clinical ophthalmic practice, especially with a better understanding of the pathologies involving the retina and vitreous and with better evidence supporting the use of these drugs. Its incidence is between  0.016%-0.026%.[1]

Post Injection Cluster-endophthalmitis (PICE)

Cluster endophthalmitis is defined as an outbreak of five or more cases on a particular day in a single operating room in the same center.[2][3]

Definition of cluster endophthalmitis
Five or more (≥5) cases on a particular day in a single operating room in the same center


The most common causative organisms have been identified as coagulase-negative staphylococci (CONS),[1] most commonly Staphylococcus epidermidis, which is fairly abundant in the conjunctival flora of the normal human eye.[4] Viridans streptococci, the second commonest group of organisms causing PIE, are also an important part of human oral flora. The following organisms are common causative pathogens[3] involved in PIE and cluster endophthalmitis:

  • Coagulase-negative staphylococci[1]
  • Viridans Streptococci
  • Staphylococcus aureus
  • Pseudomonas species.
  • Stenotrophomonas maltophilia[5]
  • Burkholderia cepacia

Risk Factors

Table 1. Risk factors for the occurrence of post-injection endophthalmitis[6]



Patient-related intrinsic factors

Counterfeit drugs[6]

Contaminated needles

Microbial flora in Conjunctival and periorbital skin

Improper drug storage

Use of same vial more than once

Nasolacrimal duct obstruction (NLDO) (pre-existing)

Lapse of cold chain

Speaking in the operating room (esp risk for Streptococcus viridans)

Diabetes (controversial)

Unsterile operating room (failure of OR sterilization)

Any localized or systemic infection (e.g. adnexal infection)
Office procedure, instead of administration in OR

Counterfeit drugs: Injection vials procured from unauthenticated sources and fake drug dealers are the commonest cause for PIE post-Avastin© (bevacizumab drug).[6] The authorized drug manufacturer and supplier for Avastin in India and many countries all over the globe is ROCHE company. The problem of counterfeit drugs became of great magnitude in 2017 when a temporary ban of Avastin© was sought in India.[7] Drugs should always be bought from authorized dealers.

Cold chain breakage/lapse:

Table 2. Various potential sites of lapse of cold chain and the preventive measures[8]

Manufacturer level Distributor level Hospital setting
Site details At Manufacturer-site From manufacturer-site to final distributor site; got as a carton At the point of use
Ideal Storage details In vials of ~0.2 ml of drug, immediately stored in cold 2-8 degrees Celsius At 2-8 degrees Celsius in a clean plastic container to prevent wetting of carton Exclusive refrigerator at 2-8 degrees Celsius with a temperature display and power backup
Other instructions for purchaser Check the cold chain log Check the cold chain log. Kezzler code of authentic drug distributor when purchasing the vial Check the cold chain log. Check for any unusual turbidity in the drug vial.

Breach in asepsis: Any breach in sterilization may lead to loss of aseptic conditions. Several activities or wrong-doing may contribute to this. These may include:

  • Speaking inside the operating room (OR) - The organisms from the oral flora may contaminate the environment
  • Failure of OR sterilization: usually, OR is sterilized using 20% v/v solution having 11% H2O2 - 1 liter/1000 cc of which is sprayed and OR closed for a contact time of 60 minutes.[9] However, the practices may vary in different parts of the world.
  • Improper scrubbing by the surgeon


Table 3. Clinical presentation of PIE and PICE[6]

Classification of PIE and PICE Usual clinical presentation
  • Fulminant
< 4 days
  • Acute
5-7 days
  • Chronic
>4 weeks

Clinical presentation usually ranges from : 24 hours to 26 days (average: 4 days)[6]

The clinical course of PIE is different from post-surgical endophthalmitis as it is usually:

  • More severe with aggressive clinical course
  • Presents earlier
  • Some virulent strains may show antimicrobial resistance to high-end antibiotics like fluoroquinolones.

History and Symptomatology

There would be a history of drug administration via the intravitreal route at an ophthalmic facility.

Patients usually present with severe pain, redness, and watering. There may be purulent discharge associated with the development of endophthalmitis.

Pain may be troublesome and often not relieved with common painkillers (e.g. NSAIDs). Patients may describe it as " severe boring'' pain.

Ocular examination

Signs on ophthalmic examination:

  • Conjunctival hyperemia
  • Circumcorneal congestion
  • Swollen lids
  • Discharge from eyes (watery/purulent/mucopurulent)
  • POOR GLOW - poor fundal glow as assessed with distant direct ophthalmoscopy / retroillumination
  • Ocular tenderness
  • HYPOPYON may be seen in fulminant cases
  • Anterior chamber (AC) reaction will be evident: AC cells and flare should be noted carefully with a 1x1 mm slit
  • Iris may be swollen with hazy details
  • In many cases, the lens or anterior vitreous details may be hazy
  • VITRITIS (Vitreous reaction) may be visible on indirect ophthalmoscopy
  • Intraocular pressure may be raised and affects the prognosis of the condition
  • Media haze
  • Fungal balls or fluffy exudates or string of pearls may be seen in fungal endophthalmitis
  • There may be associated corneal ulcer

Clinical diagnosis

PIE is a clinical diagnosis and antimicrobial drugs need to be started on an empirical basis and systemic and local therapy should be initiated as early as possible. An ultrasound B-scan will confirm the inflammatory component of the condition. AC tap, vitreous tap, or a vitreous biopsy can be taken to ascertain the microorganism causing endophthalmitis, and treatment given accordingly.

Diagnostic investigations

  4. ULTRASONOGRAPHY : USG B scan (8-10 MHz) will confirm the vitreous reaction in cases with no glow. One must assess the following in ultrasound
    • Presence of vitreous exudates
    • Chorioretinal thickness
    • Presence of retinal detachment
    • Presence of vitreous membranes

Laboratory tests

Vitreous tap or biopsy should be sent for bacterial and fungal culture and sensitivity.

Methods for obtaining a vitreous biopsy.

Methods to obtain vitreous biopsy in endophthalmitis
  • Using 23 G or 25 G vitrectomy cutter, while attaching a syringe to its aspiration tube end, before starting irrigation through pars plana port.
  • From cassette fluid of vitrectomy machine and from fluid in tubings
  • A vitreous tap may be aspirated using a 23 G needle from the pars plana region.

Differential diagnosis

  • Uveitis: A flare-up of uveitis may be mistaken for early endophthalmitis. But hypopyon is normally absent and usually less severe signs/symptoms are seen in uveitis.
  • Culture-negative sterile endophthalmitis
  • Panophthalmitis : Ocular movements will be restricted
  • Vitreous hemorrhage : There is usually an absence of anterior segment inflammation and the vitreous is reddish in color in acute vitreous hemorrhage.

Prevention of PIE and PICE

    • Thorough preoperative screening and control of risk factors like localized adnexal infection or systemic condition
    • Clean OR gown, protective cap, and footwear to patients before entering OR
    • Role of prophylactic topical antibiotics: There is a lack of evidence for their use. However, preprocedural use of topical antibiotics may be done as per the surgeon's personal experience and discretion.
    • Maintenance of cold chain should be ensured during drug procurement
    • COMPOUNDING PHARMACY - with Class 10 facility with LAMINAR HOOD FLOW facility is ideal for aliquoting of anti-VEGF drugs. In such a facility, a 100 mg/4ml vial is divided into 0.2ml vials which are sent for microbial cultures and used after 48 hours
    • Discourage bilateral injections
    • Thorough surgical scrubbing
    • Cleaning of periocular skin with 10 % povidone-iodine solution (for 3 minutes)
    • Cleaning of the conjunctival cul-de-sac with 5% povidone-iodine solution (for 3 minutes)
WHO Recommendation for surgical scrubbing (worldwide followed)
Minimum three scrubs with 4% w/v CHLORHEXIDINE GLUCONATE solution for 5-7 minutes
    • OR fumigation
    • Cultures of OR: Blood agar culture plates should be placed for 30 minutes in OR and sent for cultures
    • OR floors: Hydrogen peroxide H2O2 solution (diluted)
    • OR walls: Alcohol-based solutions, a combination of glutaraldehyde and formaldehyde (e.g. Bacillol)


Treatment must be tailored depending upon the clinical presentation of individual cases. Nevertheless, the treatment should be aggressive in PIE, maybe more than post-surgical endophthalmitis. Early surgical intervention should be preferred in these cases. Pars plana vitrectomy, if performed in time, can help remove the infection nidus in these cases.

Alternatively, one may choose to administer intravitreal antibiotics first. On the first presentation, giving empirical antibiotics (as per local microbiology department drug sensitivity information), followed later by giving specific drugs (as per the microbial culture and drug sensitivity report) is recommended.

Additional Resources

VRSI guidelines:

Guidelines for intravitreal injections: A book by Vitreo-retinal Society of India. Avastin_Guidlines_Book.pdf [Internet]. [cited 2018 Nov 28]. Available from:

OT sterilization

Sharma N, Kumar A, et al. Ocular Infections: Prophylaxis and Management. Jaypee Brothers Medical Publishers (P) Ltd., 2017.

See also


  1. 1.0 1.1 1.2 Dossarps D, Bron AM, Koehrer P, Aho-Glélé LS, Creuzot-Garcher C; FRCR net(FRenCh Retina specialists net). Endophthalmitis After Intravitreal Injections: Incidence, Presentation, Management, and Visual Outcome. Am J Ophthalmol. 2015 Jul;160(1):17-25.e1. doi: 10.1016/j.ajo.2015.04.013. Epub 2015 Apr 16. PubMed PMID: 25892127.
  2. Malhotra S, Mandal P, Patanker G, Agrawal D. Clinical profile and visual outcome in cluster endophthalmitis following cataract surgery in Central India. Indian J Ophthalmol. 2008 Apr;56(2):157–8.
  3. 3.0 3.1 Kumar A, Sundar DM, Mutha V. Commentary: The changing scenario of cluster endophthalmitis. Indian J Ophthalmol. 2018 Aug 1;66(8):1079.
  4. Grzybowski A, Brona P, Kim SJ. Microbial flora and resistance in ophthalmology: a review. Graefes Arch Clin Exp Ophthalmol. 2017;255(5):851–62.
  5. Beri S, Shandil A, Garg R. Stenotrophomonas maltophilia: An emerging entity for cluster endophthalmitis. Indian J Ophthalmol. 2017 Nov;65(11):1166–71.
  6. 6.0 6.1 6.2 6.3 6.4 Kumar A, Ravani R. Using intravitreal bevacizumab (Avastin®) – Indian Scenario. Indian J Ophthalmol. 2017 Jul;65(7):545–8.
  7. Kumar A, Tripathy K, Chawla R. Intraocular use of bevacizumab in India: An issue resolved? Natl Med J India. 2017 Nov-Dec;30(6):345-347. doi: 10.4103/0970-258X.239079. PubMed PMID: 30117450.
  8. Avastin_Guidlines_Book.pdf [Internet]. [cited 2018 Nov 28]. Available from:
  9. Sharma N, Kumar A, et al. Ocular Infections: Prophylaxis and Management. Jaypee Brothers Medical Publishers (P) Ltd., 2017.