P 238Painless acanthamoeba keratitis a case report
S. Roters, M. Severin, W. Konen, G. K. Krieglstein
Background: Acanthamoeba keratitis is a severe, painful corneal infection presenting with a variety of epithelial and stromal changes. The entity can easily be confused with herpetic or fungal keratitis, especially if no ocular pain is reported.
Case history: A 32-year old myopic female contact lens wearer presented with unilateral keratitis of unknown etiology. She recalled having had a red eye three weeks ago following extended contact lens wear. Administration of topical antiviral substances and coticosteroids lead only to temporary improvement of the condition. The affected eye was nomotonous and showed coneal edema, central stromal thickening, descemet´s striae as well as fibrin deposits on the corneal endothelium and in the anterior chamber. Visual acuity was diminished (0.1). The patient complained of photophobia but not of ocular pain.
Diagnosis: An aqueous specimen was negative for antiviral antibodies, culturing was sterile. Staphylococci could be cultured from corneal scrapings and Enterococci could be cultured from the contact lens solution. Treatment with topical and systemic broad-spectrum antibiotics reduced the signs of inflammation while the stromal infiltrate and thickening acquired an annular shape A corneal scraping obtained with a scalpel blade was cultured on nonnutrient agar overlayed with E. coli and revealed Acanthamoeba class II (6 weeks after the onset of syptoms).
Clinical course: Under treatment with propamidine, polymyxin b, neomycin, gramicidin and polyhexidine (topical) as well as fluconazole/ketoconazole (systemic) the diameter of the annular infiltrate became smaller. I the further course, the infiltrate persisted while the amount of fibrin in the anterior chamber increased. Penetrating keratoplasty was performed. Histologic examination of the host corneal tissue revealed massive infiltration with Acanthamoeba.
Conclusion: Severe pain and a history of contact lens wear are features suggestive of Acanthamoeba keratitis. The patient presented here had a history of contact lens wear (she complied with lens care regimens), but no ocular pain was reported. The characteristic annular infiltrate had a late onset. Viral or bacterial superinfection could not be ruled out. Therapeutic penetrating keratoplasty had to be performed as the condition deteriorated under agressive medical therapy, which was initiated after the late diagnosis was made.
Dept. of Ophthalmology, University of Cologne, Joseph-Stelzmann-Str.9,D-50931 Cologne