Abstract
Purpose::
To report the increased incidence of sterile endophthalmitis following intravitreal injection of triamcinolone acetonide (IVTA) in a three month period in 2006, vs. the same 3 month period in 2005.
Methods::
Charts were reviewed for all patients who underwent IVTA injections between May 1-July 31, 2006, and between May 1-July 31, 2005 at the offices of a referral vitreoretinal practice. Each injection included 4 mg /0.1 ml of unfiltered triamcinolone acetonide(KenalogTM; Bristol-Myers Squibb) from single-use vials. Patients were included if they presented with a clinical picture consistent with endophthalmitis defined as post-injection vitritis, with fibrinoid anterior chamber reaction and/or hypopyon.
Results::
Between May 1-July 31, 2006, 97 eyes underwent IVTA. Indications for injection included macular edema secondary to vein occlusion, diabetic retinopathy, exudative macular degeneration, and pseudophakia. Nine eyes (9.3%) developed an endophthalmitis. Of these nine eyes, three were phakic, and six were pseudophakic. Median presenting visual acuity (Va) was count fingers. All nine eyes underwent vitreous tap and intravitreal injection of antibiotics. All cultures and gram stains were negative for bacterial or fungal organisms. Final median visual acuity was 20/100. Triamcinolone acetonide vials from the same lot numbers were analyzed using the limulus amebocyte assay and were all found to be negative for bacterial endotoxin (<0.05 EU/ml). From May 1-July 31, 2005, 86 eyes underwent IVTA injections. One eye (1.1%) underwent a vitreous tap and intravitreal injection of antibiotics for endophthalmitis with a Va of count fingers. The gram stain and cultures were both negative for bacterial or fungal organisms. Final Va in this eye was 20/80. No patient in our series had culture positive endophthalmitis.
Conclusions::
Sterile endophthalmitis is a known complication following intravitreal injection of triamcinolone acetonide with a reported incidence of 0.1%-1.6%. Over the same three month time period, the incidence of sterile endophthalmitis increased from 1.1% (1/86) in 2005 to 9.3% (9/97) in 2006. It has been hypothesized that noninfectious endophthalmitis may represent a toxic reaction to the drug, the vehicle in which is suspended, or endotoxin in the vials in which is delivered. No endotoxin was detected in the vials from the used lots. The etiology of this nine-fold increased incidence of sterile endophthalmitis is still unclear.
Keywords: drug toxicity/drug effects • endophthalmitis • clinical (human) or epidemiologic studies: outcomes/complications