A 38-year-old man with a history of human immunodeficiency virus (HIV) infection presents to the clinic with a 1-week history of painless, blurry vision and "black spots" in his left eye. He admits to being non-adherent with his antiretroviral therapy (ART) for the past two years. His most recent CD4+ T-lymphocyte count was 22/mm3. On physical examination, visual acuity is 20/50 in the left eye and 20/20 in the right eye. Dilated funduscopic examination of the left eye reveals perivascular yellow-white, fluffy retinal infiltrates associated with prominent retinal hemorrhages extending toward the periphery. The right eye appears normal.
Which of the following is the most appropriate next step in the management of this patient?
The correct answer is:
A) Ganciclovir
This patient is presenting with cytomegalovirus (CMV) retinitis, the most common opportunistic ocular infection in patients with acquired immunodeficiency syndrome (AIDS), typically occurring when the CD4+ count is < 50/mm³. CMV retinitis is characterized by painless vision loss, floaters, or flashing lights. The classic funduscopic appearance is often described as a "pizza pie" or "ketchup and scrambled eggs" pattern, consisting of granular yellow-white opacification, due to retinal edema and necrosis, along the retinal vessels with associated intraretinal hemorrhages. The most appropriate management is treatment with antiviral therapy, typically valganciclovir (oral) or ganciclovir (intravenous or intravitreal), to prevent progression to permanent blindness or retinal detachment.
Answer choice B: Laser photocoagulation, is incorrect. While laser therapy is used to treat retinal tears or to prevent retinal detachment, a known complication of CMV retinitis due to retinal thinning and scarring, it does not treat the underlying viral infection.
Answer choice C: Oral prednisone, is incorrect. Systemic corticosteroids are contraindicated as a primary treatment for CMV retinitis, as they can further suppress the immune system and potentially accelerate viral replication and retinal destruction.
Answer choice D: Pyrimethamine and sulfadiazine, is incorrect. This is the standard treatment for ocular toxoplasmosis. While toxoplasmosis can also occur in immunocompromised patients, it typically presents as a focal, necrotizing chorioretinitis with a "headlight in the fog" appearance (due to overlying vitritis) and lacks the extensive, fluffy perivascular hemorrhages characteristic of CMV.
Answer choice E: Valacyclovir, is incorrect. Valacyclovir , or high-dose acyclovir, is used to treat acute retinal necrosis (ARN), which is usually caused by herpes simplex virus (HSV) or varicella zoster virus (VZV). Unlike CMV retinitis, ARN is typically painful and presents with well-demarcated areas of peripheral retinal necrosis that spread rapidly.
Key Learning Point
CMV retinitis is a common opportunistic infection in patients with HIV and a CD4+ count < 50/mm³. It presents with painless vision loss and a characteristic "pizza pie" funduscopic appearance (hemorrhage and yellow-white infiltrates). First-line treatment is with ganciclovir or valganciclovir.
