Risk factors, microbial profiles and prognosis of microbial keratitis-associated endophthalmitis in high-risk eyes

Microbial keratitis (MK) is a sight-threatening emergency. Delayed diagnosis and treatment may exacerbate the condition and infection may spread to the posterior segment with resultant endophthalmitis. We describe the presentation, management, visual outcomes and microbial profiles of MK-associated endophthalmitis presenting to a tertiary referral centre.

Prospective collection of data on all patients presenting with presumed MK-associated endophthalmitis from 1997 to 2007, to the Royal Victorian Eye and Ear Hospital. Outcome measures included: visual acuity, microbial profiles, and management strategy.

Thirty-seven cases of MK-associated endophthalmitis were identified over the study period, with a mean age of 73 years and 19 were male. Presenting acuities ranged from Snellen 2/60 to no perception of light (NPL). Thrity-four (91.9 %) patients had a prior history of ocular disease. Identifiable non-ocular risk factors were present in 31 (83.8 %), including steroid use, dementia, nursing home care or relative systemic immunosuppression. A culture positivity rate of 83.8 % was recorded. The most common organisms identified included: Streptococcal species in 12 (32.4 %), Pseudomonas aeruginosa in 11 (29.7 %), and Staphylococcus aureus in eight (21.6 %). Final acuities ranged from 6/36 to NPL. Sixteen (43.2 %) eyes were eviscerated/enucleated as primary treatment. Overall, 23 (62.2 %) patients required evisceration/enucleation, of which nine (39.1 %) were due to Pseudomonas aeruginosa and seven (30.4 %) to Streptococcal species (Streptococcal pneumonia).

MK-associated endophthalmitis is a serious ocular condition occurring more frequently in elderly populations, and those with long standing severe pre-existing ocular disease. Visual outcomes are poor, often requiring evisceration/enucleation.