SAEM Clinical Images Series: A Grain of Sand… or Something More Sinister?

This patient has herpes simplex virus (HSV) keratitis. Primary ocular HSV infection is usually caused by direct contact with contaminated secretions or lesions and most frequently presents as epithelial disease. Epithelial keratitis can manifest clinically as unilateral eye pain, redness, tearing, and foreign body sensation. Once affected, patients are at risk for chronic reactivation, which may be triggered by fever, trauma, menstruation, stress, or trigeminal nerve manipulation. Importantly, infectious and immunocompromised conditions predispose to reactivation. Therefore, it is essential to screen for underlying stressors such as hyperglycemia and HIV. Administration of fluorescein reveals punctate or diffuse branching ulceration (herpetic dendrites) on the cornea, as shown in this case.

The diagnosis of HSV is often made clinically, though laboratory testing of conjunctival scrapings, cytology specimens, and vesicular skin lesions may be conducted. If readily available, ophthalmology should be consulted to determine the depth of corneal involvement and associated sequelae of HSV. First line treatment for HSV keratitis includes oral antiviral treatment with acyclovir, valacyclovir, or famciclovir for 10-14 days and/or topical antiviral medications including topical ganciclovir 0.15% or trifluridine 1%. Long- term prophylaxis with oral antivirals is often considered, notably for patients at high risk of recurrence. Without adequate treatment, HSV keratitis can lead to severe vision impairment and is the leading cause of corneal blindness worldwide. All patients need urgent/emergent ophthalmology follow-up within 24 hours.

Take-Home Points

• Primary ocular HSV-1 keratitis is a leading preventable cause of blindness and classically presents with unilateral eye pain, foreign body sensation, and corneal herpetic dendrites on fluorescein exam.
• Avoid using topical steroids as monotherapy because they can suppress the patient’s immune response, allowing the herpes virus to replicate more readily, which may cause severe corneal damage, inflammation, and tissue necrosis within the stroma of the cornea. Adjuvant steroids with antiviral therapy have shown to be effective.
• It is essential to screen for infections and underlying conditions such as HIV as immunocompromised individuals are predisposed to HSV reactivation.