Acanthamoeba keratitis - Camouflage entity in Nepal

Abstract

Background Acanthamoeba keratitis is a sight threatening corneal infection and is a growing clinical problem in developing countries as well as developed countries. Acanthamoeba keratitis is a local infection of the eye and does not produce systemic illness. Proper diagnostic techniques and appropriate medical management are necessary for good prognosis. Findings We report a series of six cases of acanthamoeba keratitis diagnosed and managed at Biratnagar Eye Hospital in the year 2019. The patients age ranges from 28-58 years, with four males and two females. The mean duration of presentation to hospital was 19 days. Four patients had trauma with vegetative matter. All patients had redness, photophobia, decreased vision, pain among which only two had pain out of proportion. One patient had visual acquity of 2/60 whereas the rest had hand movement to perception of light at time of presentation. Ring infiltrate was noted in all the cases. Five patients had ulcer in central and paracentral regions, four had ulcer larger than 6mm and three showed presence of hypopyon. KOH stained smears revealed acanthamoeba cyst in all cases while Gram stain was positive in only one case. Non-nutrient agar overladen with Escherichia coli revealed feeding tracks in four cases and polymerase chain reaction revealed T4 genotype acanthamoeba in four cases. Amoebicidal treatment was started with Chlorhexidine 0.02% eye drop half hourly. Other drugs Natamicin 5% eye drop half hourly, Fluconazole 0.3% eye drop half hourly and antibiotic Moxifloxacin 0.5% eye drop half hourly were also used simultaneously. Pain was reduced in all patients. After treatment, only one patient had BCVA of 6/9 while others had visual outcome of hand movement. Conclusions Acanthamoeba keratitis can be severe and vision-threatening. Centrally located ulcer, size of the ulcer > 6mm and visual acuity Hand Movement/Perception of light at the time of presentation were associated with poor outcome. Clinically suspected lesions associated with microbiological assessment help in early diagnosis and prompt treatment.