Practice patterns in the management of fungal and acanthamoeba keratitis: a five-continent survey.

Abstract

Infectious keratitis is a frequent presentation among ophthalmological emergencies and may cause severe visual disability. The clinical presentation of fungal (FK) and acanthamoeba keratitis (AK) can be misleading and both conditions require standardized work-up procedures to avoid diagnostic and therapeutic delays. To date, there is no consensus about FK and AK diagnosis and therapeutic management (Austin et al. 2017; Szentmáry et al. 2019). To assess the current practice patterns in the early management of FK and AK, we sent a Google Forms survey presenting two clinical cases of infectious keratitis (Fig. 1) to ophthalmologists over the five continents. The complete survey is available at https://forms.gle/GCkUsEXyqTSsiNCj6. Between March and August 2019, the survey was sent to 2936 ophthalmologists. We received 237 responses (8%) from 54 countries. Among the participants, 64% were considered ocular surface specialists. Almost all respondents performed sampling for both FK (97%) and AK (96%), in accordance with the recommendation of the American Academy of Ophthalmology who advocate corneal scraping in keratitis with atypical features that suggest AK or FK. To confirm the diagnosis of FK, corneal scraping (95%) and conjunctival swab (21%) were performed in most cases. Culture (71%) and direct examination (63%) of the corneal scraping product were the most frequently requested methods to confirm AK. PCR and confocal microscopy were required in 53% and 55% of the cases, most commonly by ocular surface specialists. Confocal microscopy is a useful tool for the diagnosis of infectious keratitis when performed by an experienced operator. However, it is currently available in specialized centres only. PCR is also a useful implement because of a higher sensitivity (71%) than culture (33–53%) and a wider availability than confocal microscopy (Goh et al. 2018). Although it was presented as a very severe infection, only 60% of respondents hospitalized the case of FK, probably because of the high cost of hospitalization for both the hospital and/or patient, thereby encouraging ambulatory treatment (Prajna et al. 2007). Most practitioners prescribed topical natamycin (27%), azole agents (21%) and amphotericin B (12%) as monotherapy with an hourly frequency of instillation (80%). Dual therapy was advocate in 28% of cases. In 8% of cases, an antibiotic therapy alone was prescribed, the respondents waiting for the microbiological results before starting an antifungal therapy. An oral anti-infectious treatment was prescribed by 51% of the participants (an azole in 88% of cases). The treatment of AK is also poorly codified and our study reports a large number of different combination therapies. However, a combination of two antiseptics was the preferred treatment for 61% of the participants as advocate by most authors (Szentmáry et al. 2019). An antibiotic treatment was frequently prescribed (27%) to treat a co-infection and to reduce the bacterial flora, food source for amoebae. An oral or topical azole can be added in severe forms but was only proposed by 10% of our respondents, probably because of the participation to our survey of many practitioners working in liberal practice and/or in developing countries. Indeed, azoles are expensive and drops are compounded by hospital pharmacies only. Our study provides an updated and extended vision of FK and AK management worldwide. However, due to its international nature, there are significant geographical disparities in risk factors and microbial epidemiology (Shah et al. 2011). Consequently, empiric treatment does not always target the same microorganisms from one region of the world to another. Furthermore, some anti-infectives are not universally available. Adapting our practice patterns could enable us to optimize our anti-infective prescriptions, to improve patient’s visual prognosis and to reduce the costs of medical care.