Subretinal abscess: causative pathogens, clinical features and management.

Purpose: To review the literature on endogenous subretinal abscess (SRA).

Methods: We searched in the literature for the terms 'subretinal abscess', 'chorio-retinal abscess' and 'choroidal abscess'.

Results: A total of 122 patients were identified, of whom 20 patients (22 eyes) had no identified systemic infective foci (group 1) and 102 (120 eyes) had systemic infective foci (group 2). The mean age for group 1 was 44.6 years (range 2 weeks-82 years) and for group 2 was 43.2 years (range 1-89 years). The responsible pathogen was identified in 90% and 95% of cases, respectively. In group 1 the most frequent causative agents were Aspergillus and Nocardia, while in group 2 were Nocardia, Mycobacterium Tuberculosis and Klebsiella. In both groups the most common symptoms were reduced vision (70% and 72.5%, respectively), pain (65% and 29.4%, respectively) and redness (35% and 17.6%, respectively). For group 1 there was no difference between mean initial and final visual acuity (1.7 logMAR, range 0-3 logMAR), while for group 2 mean initial and final visual acuities were 0.8 logMAR and 0.6 logMAR, respectively. Final visual acuity was significantly better in group 2 (p = 0.003). Anterior segment inflammation was seen in 77.3% of cases of group 1 and 66.7% of cases of group 2. In both groups the abscess most common locations were posterior pole (45.4% and 32.5%, respectively) and temporal periphery (13.6% and 13.3%, respectively). Clinical features included hemorrhages (76.5% and 76.3%, respectively) and subretinal fluid (75% in both groups). Diabetes mellitus (20% and 25.5%) and immunosuppressive drug intake (35% and 23.5%) were the main predisposing factors for SRA. Combination of systemic and intravitreal antibiotics/antifungals and vitrectomy was the main therapeutic strategy for both groups. Systemic treatment alone was used mainly for cases of tubercular etiology. The timing of vitrectomy differed between the two groups, as it more commonly followed the use of systemic and intravitreal antibiotics in the forms associated with systemic infective foci. Additional abscess drainage or intralesional antibiotics were performed in 23.8% of cases.

Conclusion: At present no guideline exists for the treatment of subretinal abscess. Systemic broad-spectrum antibiotic treatment is of primary importance and should be used in all cases unless contraindicated. Combination of systemic and local treatment is the most frequently adopted strategy.