Acanthamoeba keratitis with endophthalmitis

Abstract

Acanthamoeba is a known cause of infectious keratitis, but it has rarely been reported to cause endophthalmitis. Here, we report two cases of Acanthamoeba keratitis presenting with endophthalmitis after undergoing cataract surgery. A 62-year-old female presented with ring infiltrate and peripheral thinning of the cornea in her left eye with membranous vitreous echoes on B-scan. Treatment was started based on corneal scraping and vitreous biopsy reports (smear, culture, and polymerase chain reaction [PCR]). Another 71-year-old male presented with a central 7-mm epithelial defect with stromal abscess and echoes in the vitreous cavity. Corneal scraping and vitreous biopsy were examined (smear, culture, and PCR), and treatment was started. Both patients had undergone cataract surgery on the same day at the same hospital. Both presented with clinical features of microbial keratitis and endophthalmitis. Corneal scrapings of both patients revealed Acanthamoeba cysts on smear examination and culture. Both patients were started on an hourly dosage of topical polyhexamethylene biguanide hydrochloride 0.2% and chlorhexidine 0.2% eye drops. However, no organisms were detected in culture from the vitreous samples of these patients. In case of the female with ring infiltrate, the infiltrate healed gradually with vascularization on topical therapy alone. The male with the stromal abscess had an unfavorable response to topical medications initially. Hence, intravitreal injections of voriconazole were administered twice, after which the infiltrates stopped worsening. In both cases, the eyes became phthisical. In case of endophthalmitis with smear- or culture-positive Acanthamoeba keratitis, vitreous samples should be processed for smear, culture, or PCR after centrifugation to increase the sensitivity.