Posters

Case series of atypical acanthamoeba: clinical pearls

Poster Details

First Author: A.Barua UK

Co Author(s):    E. Sykakis   D. Lake   S. Hamada              

Abstract Details

Purpose:

This case series will highlight the potential diagnostic pitfalls leading to delayed diagnosis and management of 3 rare presentations of ocular acanthamoeba to a tertiary unit. The cases will each be described, findings explained and optimal management in these cases discussed. 1 case had a very unusual lack of corneal subbasal nerve plexus leading to very little pain. The other 2 cases had unusual masquerade appearances leading to a wrong initial diagnosis. With an increasing incidence of acanthamoeba over the last decade in Europe and USA, the importance of highlighting these presentations is essential for the ophthalmic community.

Setting:

This case series was collected by the author over a period of 6 months in a Tertiary Corneal unit in ,Queen Victoria Hospital, East Grinstead, UK. All patients were seen on a regular basis during treatment, and investigations were carried out on site, except for confocal microscopy. Serial photos were taken for each patient

Methods:

3 patients were identified as having acanthamoeba keratitis. 2 were referred from a local ophthalmic unit for second opinion. Each patient was followed up closely and case note review was undertaken when a diagnosis of acanthamoeba was confirmed. 2 patients had acanthamoeba confirmed on confocal microscopy, 1 patient had epithelial biopsy confirmation, and 1 patient had donor button histopathology confirmation. Use of slit lamp high resolution photos, close clinic monitoring and request for extra information from histology and microscopy helped with the analysis. Literature review of acanthamoeba and atypical presentations along with management.

Results:

Patient 1 with granular dystrophy had FS-SALK 3 years ago, attended with suspected rejection/microbial keratitis. No improvement, graft eventually dehisced and graft excised and sent for biopsy. Significant limbal scleritis and pain. Only biopsy confirmed acanthamoeba. Recurrent AMT and topical treatment. Patient 2 referred after 6 months of topical antibiotic and steroids after testing positive for adenovirus. No improvement, sub epithelial infiltrates, reduced VA. Confocal confirmed our suspicion of acanthamoeba. Patient 3 referred after 6 weeks of topical antibiotics and steroids, no pain and relatively good VA. Presented with ring infiltrate, confirmed as acanthamoeba on confocal and epithelial biopsy. Very slow improvement, with keratouveitis. Confocal showed absence of subbasal nerve plexus. All 3 patients showing recovery.

Conclusions:

Acanthamoeba is a potentially devastating infection that has already been shown to present in a number of different forms with ocular tissue. Its early recognition is vital, as delayed diagnosis leads to prolonged treatment, morbidity and need for potential surgical treatment. This case series demonstrates presentations very rarely documented in the literature, and the common finding in each patient was contact lens wear. The masquerade is not limited to HSV epithelitis, and pain is not a pre-requisite. The use of adjunct investigative techniques must aid the diagnosis of acanthmoeba, in particular confocal and biopsy.

Financial Disclosure:

NONE