Case Report: Varicella-zoster Encephalitis with Acute Retinal Necrosis and Oculomotor Nerve Palsy.

Varicella-zoster virus is a common cause of morbidity and vision loss in patients worldwide. It can affect any structure of the eye, from keratitis to acute retinal necrosis. Rapid diagnosis and treatment significantly improve clinical outcomes and quality of life. The purpose of this study was to demonstrate a case where urgent referral to the emergency department was required to treat a patient with disseminated herpes zoster infection. This is a rare case of varicella-zoster virus encephalitis in a 70-year-old immunocompetent white man who initially presented to the eye clinic for vertical diplopia and floaters. He also had prior thoracic dermatomal rash, followed by new-onset headaches and cerebellar ataxia. Examination revealed a partial oculomotor nerve palsy in the right eye with bilateral optic disc edema and areas of retinitis consistent with acute retinal necrosis in both eyes. Polymerase chain reaction analysis of his aqueous humor and cerebrospinal fluid confirmed an active zoster infection. He received combination systemic and intravitreal antiviral medication until his retinitis resolved but required adjustments for recalcitrant disease and drug-induced nephrotoxicity. While on maintenance dosing of oral valacyclovir, he experienced reactivation in the form of bilateral vasculitis, which was successfully managed once restarting therapeutic oral dosing. This case describes a successful clinical course of acute retinal necrosis with strategies for its treatment in the setting of varicella-zoster encephalitis. Antiviral medication should be given as soon as possible, as prompt treatment has been shown to improve patient outcomes, although prognosis is typically poor in these cases. Multiple specialists are often needed to address different clinical challenges, including central nervous system involvement, viral strain resistance, disease reactivation, and drug toxicity.