Analysis from a year of increased cases of Acanthamoeba Keratitis in a large teaching hospital in the UK

Abstract

Purpose of the study: To report an observational study of Acanthamoeba Keratitis (AK) in University Hospital Coventry & Warwickshire (UHCW), Coventry, UK and determine risk factors, outcomes as well as incidence rates.

Methods: A retrospective analysis was done of consecutive patients who were treated for AK by the corneal service at UHCW from January 2017 to January 2018. Cases were identified from 2 sources; the department of microbiology and the hospital pharmacy. Patient data was collected by 3 of the authors using both paper and electronic medical records. Information was also gathered over the telephone using a predefined questionnaire. The primary endpoint used for assessing duration of disease was time to resolution after the initial diagnosis.

Results: 9 eyes were identified over the 12-month period, a drastic increase from previous years. All were contact lens (CL) wearers and 3 used daily disposable CL's. 8 out of 9 patients had an improvement in best corrected visual acuity (BCVA) which was consistent with their baseline levels pre-infection. The average length of treatment was 107.25 days for the 8 resolved cases. 1 case is still having ongoing treatment. No case has required surgical treatment. Several patients admitted to exposing their CL to unsterile water either via swimming, showering or tap water. All patients had purchased their lenses from contact lens practitioners.

Conclusion: Overall, our study shows excellent outcomes. Almost all patients had resolution of symptoms with medical treatment and an improvement in visual acuity. Several contributing factors have aided us in achieving this including early diagnosis, a robust treatment protocol and diagnostic modalities such as Polymer Chain Reaction (PCR) and Confocal Microscopy (CFM). However, the increased incidence compared to previous years is a worrying trend and there will be an ongoing analysis looking at patterns of incidence in the future.

Keywords: Acanthamoeba; Contact lens; Diagnosis; Incidence; Keratitis; Therapy.