Herpes simplex keratitis: challenges in diagnosis and clinical management

Abstract

Herpes simplex virus is responsible for numerous ocular diseases, the most common of which is herpetic stromal keratitis. This is a recurrent infection of the cornea that typically begins with a subclinical infection of the cornea that establishes a latent infection of sensory ganglia, most often the trigeminal ganglia. Recurring infections occur when the virus is reactivated from latency and travels back to the cornea, where it restimulates an inflammatory response. This inflammatory response can lead to decreased corneal sensation, scarring, and blindness. The diagnosis of these lesions as the result of a recurrent herpes simplex virus infection can at times be problematic. Currently, herpetic stromal keratitis is diagnosed by its clinical presentation on the slit-lamp examination, but the literature does not always support the accuracy of these clinical findings. Other diagnostic tests such as polymerase chain reaction assay, enzyme-linked immunosorbent assay, immunofluorescent antibody, and viral cultures have provided more definitive diagnosis, but also have some limitations. That said, accurate diagnosis is necessary for proper treatment, in order to prevent serious consequences. Current treatment reduces the severity of lesions and controls further viral spread, but does not provide a cure.

Keywords: cornea; herpes simplex virus; herpetic stromal keratitis.

Figure 1

Representative images of various corneal damages due to HSV1 infection. Notes: (A) Large herpetic epithelial dendrite at graft–host junction. (B) Large subepithelial bulla due to HSV endotheliitis. (C) Ring-lipid deposit surrounding a focal HSV disciform keratitis. (D) Large geographic herpetic ulcer in HIV patient. (E) Herpetic keratouveitis with anterior chamber inflammation (layered hypopyon due to WBC accumulation), small keratic precipitates (WBC aggregates on the corneal endothelial surface), and corneal edema (due to endothelial dysfunction). (F) Large herpetic epithelial dendrite. (G) Postherpetic neurotrophic epithelial defect due to corneal nerve damage by HSV1. (H) Large herpetic corneal scar with iris incarceration to the side of corneal perforation. Abbreviations: HSV, herpes simplex virus; WBC, white blood cell.