Abstract
Purpose: :
To report the rapid calcification of the corneal stroma associated with therapy for Acanthamoeba keratitis.
Methods: :
Pathological case report of a female with Acanthamoeba keratitis. Corneal cultures and penetrating keratoplasties were performed. The corneal specimens were sectioned and stained with hematoxylin and eosin, von Kossa, and alizarin red.
Results: :
A 46–year–old female soft contact lens wearer complained of two weeks of right eye pain and photophobia. She initially experienced a foreign body sensation after applying mascara and subsequently washed her face with stagnant rain water. Her visual acuities were CF 2 feet OD and 20/25 OS. Her right eye revealed corneal edema and a dense corneal infiltrate measuring 5.5 x 6.8 mm. There were no cells in the anterior chamber. The left eye was normal. The corneal infiltrate did not respond to topical antibiotics and the patient developed a hypopyon. Anti–acanthamoeba medications including topical neomycin, chlorhexidine, polyhexamethylene biguanide, and oral voriconazole were started after a positive corneal culture. Despite the medications, the ulcer did not heal and the patient underwent emergency therapeutic penetrating keratoplasty. The corneal specimen demonstrated numerous Acanthamoeba cysts in the stroma. Four weeks after penetrating keratoplasty and with continued anti–acanthamoeba medications, the patient developed an intra–stromal corneal infiltrate inferiorly that enlarged and extended from 3–9 o’clock. Corneal scraping and cultures from the infiltrate were negative for bacteria and fungi but the culture was positive for Acanthamoeba. It did not respond well to the anti–acanthamoeba medications combined with moxifloxacin. A second penetrating keratoplasty was performed; it showed no organisms histologically. Instead, the mid–stroma had a mass of acellular basophilic material, including many basophilic particles comparable in size to Acanthamoeba cysts. Von Kossa and alizarin red stains revealed that the deposits were calcium.
Conclusions: :
This may be the first example of dense intrastromal calcification, and it is exceptional also for the rapidity of the calcification. We speculate that it is due to an idiosyncratic effect of the combination and dosage of the topical anti–amoebic medications.
Keywords: Acanthamoeba • calcium • keratitis