A case of Epstein-Barr virus acute retinal necrosis successfully treated with foscarnet

Epstein-Barr virus (EBV) is a herpes virus known to cause infectious mononucleosis and several other human disorders. Ocular EBV infections that have been reported include uveitis, retinal vasculitis, and acute retinal necrosis (ARN). ARN is usually caused by herpes simplex virus (HSV) or varicella-zoster virus (VZV). ARN that is caused by EBV (EBV-ARN) is rarely seen, and only a few cases have been reported. The visual prognosis for EBV-ARN is poor, and no treatment strategy has been established. We report on a patient who was treated successfully for EBV-ARN.

An 80-year-old female who had been treated with prednisolone at 5 mg/day and methotrexate at 2 mg/week for rheumatoid arthritis visited our hospital because of blurred vision in her left eye. Her left visual acuity was 20/50, and extensive white-yellowish retinal lesions at the temporal periphery with retinal hemorrhages were seen through vitreous haze. The DNA sequence of EBV, but not of HSV, VZV, or cytomegalovirus, was detected by a polymerase chain reaction (PCR) assay in the aqueous humor (4.2 × 10⁶ copies/ml), with EBV also being positive in serum (3.5 × 10² copies/ml). The patient received 2 mg of intravitreal ganciclovir injections twice with a 3-day interval and intravenous infusion of acyclovir at 750 mg/day for 7 days; however, the retinal white lesions expanded rapidly, then dose of prednisolone was increased (40 mg/day) and vitrectomy was performed 10 days after the initial visit. After the surgery, the retinal lesion continued to enlarge. Vitreous samples showed high copies of EBV (1.2 × 10⁸ copies/ml). Following treatment with intravenous foscarnet (4800 mg/day), which replaced the acyclovir application, the retinal white lesions gradually diminished, leaving retinal scars. To date, the patient has developed no retinal detachment and shows visual acuity over 6/60 in the left eye along with silicone oil.

We experienced a case of EBV-ARN that was refractory to systemic acyclovir and topical ganciclovir but responded effectively to systemic foscarnet after vitrectomy. Although the clinical management remains challenging in this disease, foscarnet is considered to be one of the candidate drugs for EBV infections.