Perineural infiltrates in Pseudomonas keratitis

Case Series: Unusual Presentation of Acanthamoeba Coinfection in the Cornea

SIGNIFICANCE

The cases illustrate Acanthamoeba coinfection with Pseudomonas aeruginosa or microsporidia in the cornea.

PURPOSE

This case series aimed to alert clinicians toward considering Acanthamoeba coinfection in the cornea when unusual presentation such as perineuritis or epitheliitis was observed in clinical images. Increased suspicion of Acanthamoeba coinfection may facilitate early diagnosis and prompt management, eventually leading to good vision outcomes.

CASE SERIES

An 11-year-old boy wearing orthokeratology lens for myopia control complained of pain in the right eye for 1 week. A paracentral corneal ulcer with perineuritis was observed. Culture from corneal tissue revealed P. aeruginosa , and an in vivo confocal microscopic examination showed highly reflective and oval-shaped structures indicating Acanthamoeba coinfection. Corneal lesions gradually improved under 0.02% polyhexamethylene biguanidine, 0.1% propamidine isethionate, and 0.3% ciprofloxacin. At 1 year, the final best-corrected visual acuity was 20/25 with residual paracentral corneal opacity. Another 20-year-old man complained of pain in the right eye for 2 weeks. Multiple raised corneal lesions associated with epitheliitis were found. Moreover, 1% acid-fast staining showed oval-shaped spores, and microsporidia infection was inferred. In addition, polymerase chain reaction results obtained after subjecting the patient to corneal debridement revealed positivity for Acanthamoeba . Polyhexamethylene biguanidine (0.02%) and 0.5% moxifloxacin were prescribed, and the lesions subsided. At a 2-year follow-up, the final best-corrected visual acuity was 20/25.

CONCLUSIONS

Perineuritis in orthokeratology lens wearers and epitheliitis without any predisposing factor are unusual presentations of Acanthamoeba coinfection in the cornea. These corneal findings should arouse the suspicion of coinfection and enable the clinicians to conduct the appropriate workup and initiate adequate treatment. This case series demonstrated that early diagnosis and prompt treatment can improve visual prognosis.

Dendrite-like anterior stromal keratitis coinfected with Acanthamoeba and Pseudomonas in an orthokeratology contact lens wearer

Acanthamoeba species can cause a keratitis misdiagnosed as herpes keratitis or fungal keratitis. We report an unusual dendrite-like anterior stromal keratitis coinfected with Acanthamoeba and Pseudomonas aeruginosa in an orthokeratology contact lens wearer in Taiwan. Topical 1% voriconazole and 0.5% levofloxacin were prescribed because besides Acanthamoeba keratitis, fungal keratitis was also highly suspected initially. Topical 0.02% chlorhexidine was added after the culture of the scraped cornea showed positive results of Acanthamoeba and P. aeruginosa. The lesion subsided using this triple combination therapy for 1 week. Both Acanthamoeba and P. aeruginosa are potentially devastating causes of infectious keratitis. Our case highlights the importance of considering the possibility of a concurrent infection and atypical presentation in cases with contact lens-related keratitis. The use of topical levofloxacin combined with voriconazole should be considered as the first-line treatment in such patients.

Diagnostic Evaluation of Co-Occurrence of Acanthamoeba and Fungi in Keratitis: A Preliminary Report

PURPOSE

To test the hypothesis that the coexistence of Acanthamoeba with other forms of microbial keratitis, especially fungal keratitis (FK), is more prevalent than suspected.

METHODS

A prospective diagnostic study whereby patients presenting with stromal keratitis were additionally tested for Acanthamoeba, irrespective of the initial diagnosis. In addition to the routine workup with Gram stain, KOH mount, and cultures on blood agar and potato dextrose agar, nonnutrient agar was included. Confocal microscopy was performed where feasible. Samples for polymerase chain reaction studies were also obtained. We present the preliminary report of the first 100 culture-positive cases. The primary outcome measured was the number of coexistent Acanthamoeba and FK. The secondary outcomes were the total number of Acanthamoeba cases detected and the correlation between clinical diagnosis and microbiological observations.

RESULTS

Of the first 100 cases, 22 were culture positive for Acanthamoeba, of which 9 were associated with concurrent FK, 5 with bacterial keratitis, and 8 in isolation. However, only 2 cases were diagnosed clinically as Acanthamoeba, whereas 5 were Acanthamoeba suspects. An additional 4 cases of fungal/Acanthamoeba coexistence in keratitis were revealed purely by confocal microscopy.

CONCLUSIONS

Acanthamoeba can coexist with other forms of microbial keratitis. The frequency of infection coexistent or otherwise is higher than reported, and the possibility of coinfection must be considered especially in unresponsive cases. Including nonnutrient agar and confocal microscopy in all cases of keratitis would perhaps translate into better treatment strategies and outcomes.

The diagnosis and management of contact lens-related microbial keratitis

Contact lens-associated microbial keratitis poses a diagnostic dilemma for optometrists on two fronts. The distinction between sterile inflammation and microbial infection is often blurred. In addition, there is a requirement with nearly 50 per cent of the Australian and New Zealand optometric profession being therapeutically endorsed, to distinguish between cases of infection that can be managed in the community verses those that require escalation to public hospitals that have access to laboratory diagnostic tools and advanced imaging techniques, such as in vivo confocal microscopy. Pattern recognition and incorporation of knowledge of aetiology and risk factors assists optometrists to decide on optimal management strategies. Skilled optometrists will utilise emerging diagnostic and therapeutic technologies to ensure safe management strategies and better outcomes for these cases.

Keratoneuritis is not pathognomonic of Acanthamoeba keratitis: a case report of Pseudomonas keratitis

The presence of keratoneuritis in a radial pattern is considered to be a virtually pathognomonic sign of Acanthamoeba keratitis. We report a case of a massive keratoneuritis as a presenting sign in Pseudomonas keratitis in a contact lens wearer, thereby further challenging this concept.