An Atypical Presentation of Acanthamoeba Keratitis in a Patient With Keratoconus Treated Briefly With Topical Anesthetic

Abstract

To present a case of biopsy proven acanthamoeba keratitis requiring penetrating keratoplasty in a patient with keratoconus whose clinical course was remarkable for its lack of ocular injection and pain. The absence of these key findings may have contributed to a delay in diagnosis and a delay in instituting antiamoebic therapy. Case report. A 21-year-old woman who wore soft contact lenses for management of keratoconus presented with a painful suppurative corneal infiltrate and epithelial defect. The patient was initially seen in an emergency department where she was given a bottle of topical anesthetic drops (proparacaine) to use for pain. When she was seen by the authors 18 hr after presenting to the emergency department, the proparacaine was immediately discontinued, and she was treated with fortified antibiotic (vancomycin and tobramycin) eye drops and oral antiviral medications (famciclovir). Despite an initial improvement and complete resolution of ocular discomfort, the patient went on to develop a dense, peripheral stromal infiltrate that failed to improve despite intensive treatment. Confocal microscopy and corneal biopsy were definitive for acanthamoeba infection. The patient subsequently failed medical therapy and underwent large diameter penetrating keratoplasty. The patient has shown no evidence of acanthamoeba recurrence in the corneal graft. Keratoconic patients may have atypical presentations of acanthamoeba keratitis, which may delay diagnosis and institution of medical therapy. Even brief use of topical anesthetics may further complicate the clinical picture.