Kyrieleis Arteriolitis Associated with Acute Retinal Necrosis due to Herpes Simplex Virus Type 1 Secondary to Herpetic Encephalitis

We report the case of a 52-year-old woman who presented to the emergency department with acute retinal necrosis in her left eye secondary to herpes simplex virus type 1 encephalitis for which she had been hospitalized four months before. Treatment with intravitreal foscarnet and intravenous acyclovir was promptly commenced followed by the addition of oral prednisolone. PCR analysis of aqueous humor detected HSV type 1 DNA. The condition responded to therapy with partial resolution of intraocular inflammation and improvement of visual acuity, but the presence of Kyrieleis plaques was observed two weeks after the initiation of treatment, when five intravitreal foscarnet injections had been administered. The patient was switched to oral therapy with valacyclovir, and 10 weeks after commencing treatment, the patient’s left eye was free of inflammation, having achieved a BCVA of 20/20. Oral steroid treatment was gradually tapered off, and the patient was instructed to remain on prophylactic antiviral therapy. Kyrieleis arteriolitis is an uncommon finding in the context of acute retinal necrosis. As far as we are aware, we report the first case of Kyrieleis arteriolitis in acute retinal necrosis secondary to viral encephalitis and the second one presenting Kyrieleis plaques in acute retinal necrosis caused by herpes simplex virus type 1. Prior reports of cases of Kyrieleis arteriolitis in acute retinal necrosis are also presented.