Effective diagnosis by real-time PCR of herpes simplex diffuse endotheliitis that is similar in appearance to fungal keratitis: case series

Abstract Purpose Herpes simplex diffuse endotheliitis with accompanying feathery infiltration is difficult to diagnose due to corneal findings that are similar to fungal keratitis. This case series reports on the effectiveness of using real-time polymerase chain reaction (PCR) to diagnose herpes simplex diffuse endotheliitis that is similar in appearance to fungal keratitis. Methods After extracting corneal smear sample DNA, samples were then applied to two independent PCR assays, a qualitative multiplex 24-pathogen strip PCR assay, and a quantitative real-time PCR assay of herpes simplex virus type 1 (HSV-1). Results All 3 cases showed ciliary injection, feathery infiltration in the corneal stroma and hypopyon, which are corneal findings similar to that observed for fungal keratitis. Retrocorneal plaques, which showed clear boundaries between the corneal endothelial surfaces and retrocorneal plaques in anterior segment optical coherence tomography, were observed in 2 out of 3 cases. Corneal scraping was performed in all cases, followed by initiation of antifungal treatment. However, real-time PCR of the corneal scraping detected 6.0 × 106, 1.0 × 105 and 5.0 × 105 copies/μg glyceraldehyde 3-phosphate dehydrogenase (GAPDH) of HSV-1 DNA per each microgram of the samples. Fungi were not cultured in any of the cases. After switching the medication from antifungal to antiviral, the feathery corneal infiltration was cured with only mild scarring. Conclusions Real-time PCR was an effective tool in diagnosing HSV diffuse endotheliitis with feathery infiltration. Topical corticosteroids in conjunction with oral and topical antivirals were an effective treatment.