Associated factors, diagnosis and management of Acanthamoeba keratitis in a referral Center in Southern China

Abstract

BackgroundTo analyse the associated factors, diagnosis, clinical manifestations and therapeutic effects of Acanthamoeba keratitis at a tertiary ophthalmic centre in Southern China.MethodsA retrospective clinical study was performed in fifteen patients who were admitted to Zhongshan Ophthalmic Centre (ZOC) from January 2004 to December 2014. The patients’ pathogenesis-associated factors were analysed, and preoperative diagnoses were determined using corneal scraping cultures and/or confocal microscopy followed. All diagnoses were confirmed by postoperative pathological examinations. At follow-up, best-corrected visual acuity (BCVA), the recurrence rate and graft transparency were evaluated to assess therapeutic effects.ResultsThe main pathogenic factors observed in the fifteen patients were a history of injury or a foreign body entering the eyes (12 cases). In all, Acanthamoeba keratitis was preoperatively diagnosed in 5 cases using corneal scraping cultures or confocal microscopy. Ocular symptoms included redness, photophobia, tearing, and blurred vision. Penetrating keratoplasty was performed in thirteen patients, and postoperative pathological examinations were performed to confirm these diagnoses. The logarithm of the minimum angle of resolution (logMAR) of visual acuity was significantly improved after keratoplasty (p < 0.01). No recurrence was observed, and approximately 90% of the corneal grafts were found to be transparent during the follow-up period.ConclusionsCorneal trauma may be the main pathogenic factor that causes Acanthamoeba keratitis in southern China. Corneal scraping combined with confocal microscopy was helpful for achieving a correct diagnosis. Early keratoplasty combined with amoebicidal therapy is an effective treatment strategy in Acanthamoeba keratitis.

Acanthamoeba keratitis: a review of biology, pathophysiology and epidemiology

“…Reviews have shown that AK is a rare but severe corneal infection 13,63 caused by the species Acanthamoeba. 4,22,[64][65][66][67][68][69] It is painful and difficult to diagnose and treat 1,5 and can lead to blindness or even enucleation. 16,20,28,32,34,38,56,[70][71][72][73] The devastating risk of vision loss is connected to scarring and corneal ulceration, 74 causing massive ocular injury.…”

“…88 AK cases in China may also be related to soil-contaminated matter and corneal trauma. 65 Lorenzo-Morales et al noted that between 1980 and 1990, the incidence of AK worldwide was relatively low, at 1-2 cases per million CL wearers, 16 while the relationship between the use of CLs and AK was first established in 1984. 31 With a rise in the number of CL wearers, a direct increase of reported cases was observed.…”

Acanthamoeba Ocular Infection: Anomalous Presentation of a Potentially Vision-Threatening Condition

“…Acanthamoeba keratitis is a rare and vision-threatening condition [1]. The clinical picture may be various but some findings are believed to be typical: the unilateral presentation, a history of CL wearing, diffuse corneal haze, radial keratoneuritis and a ring-shaped stromal infiltrate [1,2,4]. Among symptoms, blurred vision and disproportionate pain are frequently reported, with the latter being largely considered pathognomonic of AK [11].…”

“…Soft CL are known to be at increased risk than rigid gas permeable (RGP) lenses [2]. AK may have a proteiform presentation [3,4]. At the onset, signs and symptoms are often aspecific and the clinical picture may be mistaken as a fungal, bacterial or viral infection leading to a delay in the diagnosis.…”

Identification and Genotypic Characterization of Potentially Pathogenic Acanthamoeba Isolated from Tap Water in Wuxi, China

“…The number of infection cases is increasing every year owing to the increase in the number of contact lens wearers who do not comply with recommended hygiene practices and even rinse their contact lenses with tap water [4,5]. Additionally, an increase in the number of cases of AK has been reported in China [6]. Because of all the threats and their dangerous effects on human health, the early detection of pathogenic Acanthamoeba in environments is essential.…”