Viral Retinitis in the Cancer Patient

Abstract

Viral retinitis is a vision-threatening infection of the retina that can occur in both immunocompetent and immunocompromised patients and is primarily caused by the human herpesvirus family of viruses. Prompt recognition and treatment are critical for optimal outcomes. This chapter focuses on cytomegalovirus (CMV) retinitis, acute retinal necrosis (ARN), and progressive outer retinal necrosis (PORN). Presentations of CMV retinitis range from an indolent/granular retinitis to a fulminant/edematous retinitis characterized by necrosis and hemorrhage. ARN is a vaso-occlusive necrotizing retinitis that is usually secondary to herpes zoster or HSV. PORN is characterized by primary involvement of the outer retina, minimal to no vitreous inflammation, and extremely rapid progression. Treatment of CMV retinitis consists of improving the patient’s immune status and then administering induction and maintenance antiviral therapy. For ARN, intravenous acyclovir is the standard initial treatment; oral acyclovir is then employed for variably prolonged periods. Because of PORN’s poor prognosis, a multidisciplinary approach with an infectious disease consultation is favored. In patients with viral retinitis, argon laser photocoagulation posterior to the edge of necrosis may be performed as prophylaxis against retinal detachment, which is the major cause of visual loss after acute manifestations have resolved. Retinal detachments in patients with CMV retinitis have been approached with scleral buckling, gas pneumatic retinopexy, and vitrectomy with either gas or silicone oil tamponade. Visual prognosis is guarded for patients with CMV retinitis or ARN and extremely poor for patients with PORN.