| The in vivo confocal microscopy technique provides us with a real-time, non-invasive way of examining the human cornea. The most important advantage of this type of microscopy is to reveal the etiologic agents in infectious keratitis such as acanthamoeba keratitis. We present several representative cases of acanthamoeba keratitis, which were diagnosed in their early stages using in vivo confocal microscopy and managed based on that diagnosis. In our acanthamoeba keratitis cases, highly-reflective round or ovoid organisms with a diameter of about 10-25 um were visualized distinctly against relatively-dark normal parenchymal structures, such as epithelial cells or keratocyte nuclei. Double-walled structures of Acanthamoeba cysts were clearly demonstrated in some cases. We can confirm that in vivo tandem scanning confocal microscopy is a powerful diagnostic tool for identifying the infecting organisms in Acanthamoeba keratitis. ( info) |
| OBJECTIVE: To evaluate the efficacy of chlorhexidine solution in the treatment of patients with acanthamoeba keratitis. DESIGN: Prospective nonrandomized study. PARTICIPANTS: Five patients infected with culture-proven acanthamoeba keratitis. INTERVENTION: chlorhexidine solution was used hourly on six eyes and gradually reduced to four times a day after 1 month. Follow-up ranged from 1 to 10 months (mean, 4 months). MAIN OUTCOME MEASURES: Severity of symptoms and signs, time for healing, and final visual acuity. RESULTS: Clinical results in four patients showed improved visual acuity, with a rapid recovery within 1 week. No adverse drug reaction was encountered, but one patient with a perforated ulcer developed glaucoma. Eighty-three percent of 6 eyes were medically cured with chlorhexidine and recovered visual acuity 6/18 or better. Four of five patients improved within 3 weeks, with resolution of infiltration and healing of epithelial defects. By 2 to 3 weeks, visual acuity 6/18 or better had improved in four (66.7%) of six eyes and recovered 6/6 in two eyes (33.3%). Bacterial coinfection occurred in one eye. CONCLUSION: chlorhexidine dramatically hastened clinical improvement in all eyes and is a successful medical therapy that has excellent results in patients who are diagnosed early. ( info) |
| PURPOSE: To report live, active trophozoites in an eye with acanthamoeba keratitis that resembled Acanthamoeba polyphagia in the anterior chamber fluid obtained by transcorneal tap. METHOD: After prediagnostic therapy had failed, we performed cryosurgery to break the corneal cell walls and treated the patient with oral fluconazole. RESULTS: The condition resolved after 8 weeks of oral fluconazole therapy. Residual leukoma was treated by corneal graft. CONCLUSION: Live, motile Acanthamoeba can be isolated from an anterior chamber tap; combination therapy with oral fluconazole after corneal cryosurgery may be effective. ( info) |
4/100. Severe Acanthamoeba sclerokeratitis in a non-contact lens wearer. PURPOSE: To report a case of severe Acanthamoeba sclerokeratitis. methods: A 70-year-old male non-contact lens wearer was examined for severe pain in the left eye which began about 40 days after cataract surgery. In spite of a careful search, it required 6 weeks to detect Acanthamoeba. Systemic and topical fluconazol and miconazol did not help and the keratitis progressed into necrotic sclerokeratitis with protrusion of uveal tissue through the thin sclera. RESULTS: Those findings slowly got worse before the Acanthamoeba sclerokeratitis resolved 6 months later with scar formation. CONCLUSION: We describe the terminal and cicatricial stages of acanthamoeba keratitis, and report that the healing process can follow the terminal stage and the eye does not need to be enucleated. ( info) |
5/100. Treatment of acanthamoeba keratitis combined with fungal infection with polyhexamethylene biguanide. From July 1996 to March 1997, three cases of acanthamoeba keratitis combined with fungal infection were diagnosed and treated at our ophthalmic department. Specimens from all of these cases were obtained by corneal scraping, keratectomy and anterior chamber paracentesis. The diagnosis was confirmed by either the results of smear test or pathology reports. All of these patients received aggressive treatment with polyhexamethylene biguanide (PHMB) 0.02%, fluconazole, and anegyn eye drops. After the infection had been controlled without extension, therapeutic penetrating keratoplasty was performed on all of these patients despite the existence of infiltration beyond the edge of the graft. Postoperatively, eye drops were tapered gradually, and treatment was continued for 1 to 2 months. All three cases achieved good results and there was no recurrence of infection. Two cases had visual acuity of 20/100 and 20/20, while the other one perceived hand movement only due to later graft rejection. These cases suggest that early diagnosis and immediate use of PHMB and anti-fungal agents are effective in the treatment of acanthamoeba keratitis combined with fungal infection. ( info) |
6/100. Unusual case of Acanthamoeba polyphaga and pseudomonas aeruginosa keratitis in a contact lens wearer from Gauteng, south africa. Acanthamoeba species can cause a chronic, progressive ulcerative keratitis of the eye which is not responsive to the usual antimicrobial therapy and is frequently mistaken for stromal herpes keratitis. An unusual case of coinfection with Acanthamoeba polyphaga and pseudomonas aeruginosa as causes of corneal keratitis in a contact lens wearer from Gauteng, south africa, is reported. These two pathogens have previously been assumed to be selectively exclusive. cysts of the isolated acanthameba tolerated an incubation temperature of 40 degrees C, indicating a pathogenic species. This case highlights the importance of culture methods in the diagnosis of corneal infection and the choice of treatment regimen. The patient's history of careless contact lens-disinfecting habits emphasizes the need to adhere strictly to recommended methods of contact lens care. ( info) |
| acanthamoeba keratitis, common in soft lens wearers, is not commonly isolated. The reports of acanthamoeba keratitis in Indian literature are few. We report here a case of acanthamoeba keratitis in a medical student using soft contact lenses, initially diagnosed and treated as a bacterial and later as a viral corneal ulcer, who responded extremely well to medical line of therapy. ( info) |
8/100. Heterogeneity in cyst morphology within isolates of Acanthamoeba from keratitis patients in thailand. We isolated Acanthamoebae from the first two keratitis patients identified in thailand in 1988 and 1990. The patients developed decreased vision, severe photophobia, severe eye pain and foreign body sensation after minor corneal trauma. The lesions included generalized superficial punctate keratitis, stromal corneal ulcer with keratic precipitate and uveitis in one case, and corneal ulcer with abscess in the other. Both cases were diagnosed by isolation of characteristic trophozoites and cysts of Acanthamoeba from corneal tissue by non-nutrient agar culture method. Based on cyst morphology, A. castellanii and A. polyphaga were detected in one case, and A. castellanii and A. triangularis in the other. Restriction fragment length polymorphism analysis of mitochondrial dna (mtDNA-RFLP) revealed that each patient harboured a single parasite population. One shared mtDNA-RFLP with an authentic strain of A. castellanii, and the other gave a new unique pattern. Thus species identification of Acanthamoeba based on cyst morphology per se can be arbitrary, and mtDNA-RFLP may be more appropriate for accurate species/strain differentiation amongst morphologically heterogeneous populations of Acanthamoebae. ( info) |
9/100. Discrimination between clinically relevant and nonrelevant Acanthamoeba strains isolated from contact lens- wearing keratitis patients in austria. Eighteen cases of Acanthamoeba-associated keratitis among contact lens wearers seen at the Department of ophthalmology, Karl-Franzens-University, Graz, austria, between 1996 and 1999 are reviewed. The amoebae were proven to be the causative agents in three patients. The aim of our study was to discriminate between clinically relevant and nonrelevant isolates and to assess the relatedness of the isolates to published strains. Altogether, 20 strains of free-living amoebae, including 15 Acanthamoeba strains, 3 Vahlkampfia strains, and 2 hartmannella strains, were isolated from clinical specimens. The virulent Acanthamoeba strains were identified as A. polyphaga and two strains of A. hatchetti. To our knowledge this is the first determination of keratitis-causing Acanthamoeba strains in austria. Clinically relevant isolates differed markedly from nonrelevant isolates with respect to their physiological properties. 18S ribosomal dna sequence types were determined for the three physiologically most-divergent strains including one of the keratitis-causing strains. This highly virulent strain exhibited sequence type T6, a sequence type not previously associated with keratitis. Sequence data indicate that Acanthamoeba strains causing keratitis as well as nonpathogenic strains of Acanthamoeba in austria are most closely related to published strains from other parts of the world. Moreover, the results of our study support the assumption that pathogenicity in Acanthamoeba is a distinct capability of certain strains and not dependent on appropriate conditions for the establishment of an infection. ( info) |
10/100. Corneal co-infection with scedosporium apiospermum and Acanthamoeba after sewage-contaminated ocular injury. PURPOSE: To describe a corneal co-infection with the fungus scedosporium apiospermum and Acanthamoeba that result in spontaneous corneal perforation. methods: A 27-year-old man presented due to severe ocular pain in his left eye caused by a corneal ulcer. The patient was injured 7 days before presentation by metallic thread contaminated by sewage. Corneal scrapping and deep stromal biopsy were obtained and stained for microscopic evaluation with periodic acid-Schiff, Giemsa, and Gomori's methenamine silver stains. Samples were sent for aerobic and anaerobic bacterial and fungal cultures. RESULTS: Corneal biopsy and corneal scrapping showed viable Acanthamoeba cysts in the corneal stroma and S. apiospermum micelle, respectively. The fungal culture was sensitive to ketoconazole, miconazole, econasole, and traconazole. Devastating corneal perforation occurred despite aggressive antifungal and antiamoebic topical and systemic treatment initiated after diagnosis. The corneal button showed a necrotic tissue devoid of inflammatory cells and microorganisms. CONCLUSION: S. apiospermum and Acanthamoeba may co-infect immune privilege sites, such as the cornea, in immunocompetent hosts. Compromised corneal surface, e.g., after trauma by sewage-contaminated objects, may increase the susceptibility for such devastating coinfection. Prevention may be possible by use of protective eyewear by high-risk individuals. Treatment should be initiated promptly with broad-spectrum antimicrobial agents after ocular injury by sewage-contaminated objects. Repeated corneal cultures and biopsies, if the cultures are negative, are warranted. Corticosteroids should be withheld until the causative agents are identified and targeted treatment is initiated. ( info) |