Microsporidial Stromal Keratitis: Successful Treatment with Topical Voriconazole and Oral Itraconazole

Abstract

We report a case of microsporidial stromal keratitis successfully treated with topical voriconazole and oral itraconazole. A 30-year-old Hispanic male construction worker who wears contacts lenses presented with left eye erythematous, epiphora, and mild pain increasing over few days after failing previous antibiotics treatment. His best corrected visual acuity in the left eye was count fingers at three feet, and the slit lamp examination showed 3+ conjunctival injection, a circular central corneal ulcer 3.2 mm in diameter, stromal thinning, and an anterior chamber with white cells, flair, and 0.1 mm hypopyon. A cornea punch biopsy identified microsporidial organisms with some features suggestive of Vittaforma corneae. After treatment with topical voriconazole and oral itraconazole for eight weeks, the patient had complete resolution with no recurrence for over 12 months of follow-up. To our knowledge, this is the first reported case of successful treatment of microsporidial stromal keratitis with antifungals.

Microsporidial keratopathy in two dogs

“…The stromal microsporidial keratopathy in both of these dogs is comparable to the stromal keratitis reported in people. The lack of a significant inflammatory response and the absence of neovascularization were striking in both cases, and this is similar to that reported in some immunocompetent human patients . The term keratopathy as opposed to keratitis was chosen to describe the corneal pathology in these two dogs in the absence of an inflammatory infiltrate.…”

“…The lack of a significant inflammatory response and the absence of neovascularization were striking in both cases, and this is similar to that reported in some immunocompetent human patients. 16,25 The term keratopathy as opposed to keratitis was chosen to describe the corneal pathology in these two dogs in the absence of an inflammatory infiltrate. The authors recognize, however, that the term microsporidial keratitis is used throughout the human literature and that the presence of infectious organisms in conjunction with the clinical presence of pain could justify the use of similar terminology in these two dogs.…”

“…20,[30][31][32] In contrast, cases of microsporidial stromal keratitis are commonly refractory to medical treatment and typically require penetrating keratoplasties. 17 Rare reports of successful medical therapy in cases of stromal keratitis, however, include oral itraconazole, 17 topical 1% voriconazole and oral itraconazole, 25 and 0.02% topical chlorhexidine gluconate with oral albendazole. 33 In medically refractory cases, full-thickness corneal transplants appear to be required for successful eradication of stromal microsporidial keratitis.…”

A Narrative Review of Microsporidial Infections of the Cornea

“…Transmission electron microscopy (TEM) [4], light microscopy (LM) ± tissue staining [50], histopathology [4], polymerase chain reaction (PCR) [50], in vivo confocal microscopy (IVCM) [4,6], anterior segment optical coherence tomography (AS-OCT) [4,5] Treatment options Self-limiting [66]; most often treated with monoor combination therapy consisting of topical fumagillin [7], oral albendazole [55], topical antibiotics [60], topical antifungals [62], and/or topical antiseptics [66] Usually requires corneal graft transplantation [71], though some reports exist of resolution with medical therapy alone [20,[68][69][70] Prognosis Excellent [56] Guarded [6,8] lamp biomicroscopy of MSK most often reveals diffuse multifocal mid-to deep stromal infiltrates with mild to moderate conjunctival injection, stromal edema, and endothelial exudates. The overlying epithelium is typically intact, though rarely epithelial defects may be visible over the stromal lesions ( Fig.…”

“…MSK carries a poor prognosis and tends to be resistant to medical therapy [68], though a few cases exist of successful treatment with a combination of topical and systemic antimicrobials. Sangit, Murthy, and Garg were the first to describe a case of MSK that was responsive to medical therapy; a combination of 0.02% topical chlorhexidine gluconate hourly and 400 mg oral albendazole twice daily given for 12 weeks resulted in complete resolution in a 14-year-old girl [69].…”