Metastatic bacterial endophthalmitis: a contemporary reappraisal

Metastatic bacterial endophthalmitis remains a challenge to the clinician despite the success of antibiotics in reducing its frequency and severity. Controversy currently surrounds the management of this condition because of uncertainty about the value of and indications for vitreous surgery. We review 72 cases of metastatic endophthalmitis from the past decade, including five not previously published. The spectrum of causative bacteria changed significantly during this period, with displacement of meningococcus by Bacillus cereus as the most frequently reported agent and an increasing incidence of infection by organisms of low pathogenicity in immunologically compromised hosts. We propose a new classification scheme for metastatic endophthalmitis based on the location (anterior or posterior segment) and extent (focal or diffuse) of the primary intraocular infection. Focal and anterior cases appear to have a good prognosis, while posterior diffuse disease nearly always leads to blindness. Our analysis of outcomes suggests that systemic antibiotics are more valuable in metastatic than in postoperative or traumatic endophthalmitis and that intraocular antibiotic injection and vitrectomy make only a limited contribution to successful treatment in metastatic infection. We recommend a clinical approach to metastatic endophthalmitis that minimizes exposure of patients to the risks of invasive procedures.