We read with great interest the article by Ang and associates describing prognostic factors and outcomes in endogenous Klebsiella pneumoniae endophthalmitis (EKE) . We appreciate this report, which provided us with valuable information on EKE. Although the study was concise, we have some concerns regarding the findings presented.
The authors concluded that patients with hypopyon and unilateral involvement have poor prognoses. They speculate that pupillary hypopyon is produced by inflammatory cells and cellular debris permeating through the zonules to enter the anterior chamber from the vitreous gel. In addition, we postulate that inflammatory cells migrating from anterior uveal tissue also contribute to pupillary hypopyon production. Some early-stage patients have anterior focal or diffuse hypopyon with or without posterior focal type and may be treated successfully with intravitreal antibiotics. In our experience (not published), patients with this type of hypopyon have more favorable prognoses. However, patients with hypopyon and posterior diffuse EKE associated with large subretinal or choroidal abscesses, especially in the submacular area, usually have poor prognoses, even after pars plana vitrectomy. Therefore, the prognosis seems to be related to the extent of posterior segment involvement, especially in panophthalmitis. Bilateral involvement usually results in differing severities of endogenous endophthalmitis. The eye with later onset tends to experience milder ocular inflammation and a more favorable visual outcome. In our clinical experience, unilateral involvement is not associated with an increased likelihood of evisceration.
The role of corticosteroids in treatment of EKE is controversial and was not analyzed in the authors’ study. Intravitreal corticosteroids are recommended in the treatment of severe vitreous inflammation, especially in patients showing poor response to initial intravitreal antibiotics. The Endophthalmitis Vitrectomy Study and other reports indicate that subconjunctival antibiotics are not necessary in the treatment of endophthalmits. However, we recommend subconjunctival antibiotics and corticosteroids for the treatment of panophthalmitis with subconjunctival and scleral abscesses. We have demonstrated that multiple injections of combined intravitreal and subconjunctival antibiotics with corticosteroids significantly resolve panophthalmitis with subconjunctival and scleral abscesses and prevent evisceration.
Klebsiella pneumoniae isolates resulting in EKE usually are susceptible to ceftazidime, amikacin, and carbapenem. Forty-eight to 72 hours after administration, most antibiotics are eliminated, so if response is limited, intravitreal injection should be repeated. In the case of a panophthalmitis eye with no light perception, a high dose (4 to 5 mg in 0.05 mL) of intravitreal ceftazidime has prolonged bactericidal effects on Klebsiella pneumoniae and prevents corneal and scleral rupture over the melting area that would result from high intraocular pressure after intravitreal injection.
Finally, we are interested in how patients with different types of EKE, according to the Greenwald classification, can achieve favorable visual outcomes or may require evisceration after various treatments. Final visual outcomes usually are related to posterior segment involvement in patients with EKE, and evisceration is associated with corneal or scleral melting in panophthalmitis. If the authors can supply these data, their study would provide a valuable reference for clinical practice.