Microsporidial Spores can Cross the Intact Descemet Membrane in Deep Stromal Infection
A 26 year old healthy male presented on November 1, 2008 with a one-year history of recurrent redness, pain and watering in the right eye. The patient was a non-diabetic, with good general health and nutritional status. The condition waxed and waned despite multiple ophthalmology consults, and therapy that included topical antibiotics, corticosteroids and oral antiviral medication. Best-corrected visual acuity (BCVA) was counting fingers at one meter. Slit lamp examination showed intact, edematous epithelium, while the underlying stroma showed multiple, gray-white irregular to oval shaped flocculent infiltrates with indistinct borders; diffusely distributed over the entire cornea (except the limbus), involving the deep stroma [Figures and ]. Endothelial exudates were also noted. The left eye was essentially normal.\nCorneal scrapings were obtained. The smear revealed multiple oval, spore-like structures, with a waist-band which was Gram positive, 1% acid fast positive and showed blue fluorescence on potassium hydroxide with calcofluor white stain, confirming a diagnosis of microsporidial stromal keratitis. Medical therapy was instituted with topical 0.02% chlorhexidine gluconate ever half-hour and oral albendazole 400mg twice daily; however here was no response even after three weeks []. The patient underwent penetrating keratoplasty.\nSurgery was performed under local anesthesia. A 9.5mm corneal graft was sutured with 16 interrupted sutures into a 10 mm recipient bed. The entire area of inflitrated corneal tissue was excised. Postoperatively, the patient was prescribed topical chlorhexidine 2% eight times a day (formulated in the hospital pharmacy) which was discontinued after three weeks, topical prednisolone acetate 1% eight times a day tapered over the next several months, and topical atropine sulphate 1% three times a day for two weeks. There was with no recurrence postoperatively. The visual acuity improved to 20/20 within two months []. However, a year later, the patient presented with severe allograft rejection (he had stopped topical steroids) and subsequently the graft failed. An endothelial keratoplasty was performed and the patient was doing well at the last follow-up, two years postoperatively. The histopathology of the corneal button revealed an ulcerated cornea with dense inflammatory infiltrates in the stroma composed of neutrophils, lymphocytes and plasma cells with stromal necrosis. Numerous microsporidial spores were present in the deeper stroma upto the DM [Figures –] on Gram stain and 1% acid-fast stain. The DM itself was intact throughout the specimen. The AC exudates noted in some sections showed the presence of microsporidial spores [ arrow].