A 43-year-old man comes to the emergency department due to painless, progressive visual impairment. The patient was diagnosed with sexually acquired HIV infection 4 years ago. He was previously started on antiretroviral therapy but has been noncompliant with his prescribed medications. His most recent CD4 count was 37 cells/mm³. Physical examination shows no skin rash or corneal lesions. Funduscopy reveals the findings seen in the image below. Which of the following medications is the best initial therapy for this patient?

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Quizplus · Accepted Answer

11ec160b_3c21_9dd7_9249_5b69f95ead71_MD0001_00 Patients with untreated AIDS who have CD4 counts <50/mm³ are at high risk for cytomegalovirus (CMV) retinitis. Suspicion is often raised when a patient with advanced AIDS develops slowly progressive blurred vision, scotoma (blind spots), floaters, or photopsia (flashing lights). Although most cases are thought to arise due to hematogenous dissemination of CMV, serum testing for the virus is often (~50%) negative. Therefore, the diagnosis is typically established when funduscopy reveals yellow-white, fluffy retinal lesions near the retinal vessels associated with hemorrhage. Treatment is required to prevent progression and blindness. Ganciclovir, a guanine nucleoside analogue that is structurally similar to acyclovir but expresses greater activity against CMV DNA polymerase, is first-line therapy. Patients are also typically started on antiretroviral therapy to increase CD4 count. A major complication of CMV retinitis is retinal detachment due to the replacement of damaged retina with thin, atrophic scar tissue (which is prone to tear). (Choice A) Acyclovir is used to treat herpes simplex (HSV) and varicella zoster virus (VZV) infections. Although these infections occasionally cause acute retinal necrosis, most cases arise in older, immunocompetent individuals (not patients with advanced AIDS). In addition, HSV retinitis and VZV retinitis are usually associated with significant vitreal inflammation, spotty peripheral retinal lesions, and infrequent hemorrhage. (Choice B) Candida endophthalmitis is treated with amphotericin B. Funduscopy usually reveals focal, white, mound-like lesions on the retina. Most cases occur in the setting of an indwelling central venous catheter or total parenteral nutrition. (Choice C) Clarithromycin is used in conjunction with other antibiotics for the treatment of Mycobacterium avium complex infection, which usually causes fever, night sweats, abdominal pain, and diarrhea. (Choice D) Cryptococcus neoformans infections are treated with flucytosine, a fluorinated analog of cytosine, in combination with amphotericin B. Although cryptococcal endophthalmitis can occur in patients with advanced AIDS, it is much less common than CMV retinitis, and patients often have other manifestations of cryptococcal infection such as skin lesions or meningoencephalitis. (Choice F) Penicillin G is used to treat ocular (and neuro-) syphilis. Ocular syphilis often presents as uveitis but can cause retinitis, which usually appears as ground-glass lesions with significant vitreal inflammation. Most patients also have manifestations of syphilitic meningitis (eg, headache, vomiting). Educational objective: Cytomegalovirus retinitis is the most common cause of ocular disease in patients with untreated AIDS who have CD4 counts <50/mm³. Diagnosis is made by funduscopy, which typically reveals yellow-white, fluffy retinal lesions near the retinal vessels with associated hemorrhage. Treatment with ganciclovir is required to prevent blindness.

A 43-Year-Old Man Comes to the Emergency Department Due to Painless