Review Question - QID 217083

This HIV-positive patient who is poorly-compliant with antiretroviral therapy (ART) and has a presentation of new-onset floaters, poor vision in the right eye, CD4 T-lymphocyte count of 45 cells/mm^3, and whitish perivascular lesions with hemorrhagic necrosis on retinal imaging likely has cytomegalovirus (CMV) retinitis. Oral valganciclovir is a first-line treatment for CMV retinitis.

CMV retinitis is an opportunistic infection that affects immunosuppressed patients, such as patients with HIV infection with a CD4 count less than 50 cells/mm^3. CMV retinitis is caused by cytomegalovirus, a double-stranded DNA virus in the herpesviridae family that reaches the retina hematogenously and infects the vascular endothelium with spread to retinal cells. CMV retinitis may present with decreased visual acuity, floaters, flashing lights, or blind spots; however, over half of the cases of CMV retinitis are asymptomatic. On physical exam, CMV retinitis usually presents with whitish lesions along the retinal vasculature with prominent hemorrhage that appears like a “pizza pie” or “cottage cheese with ketchup.” Treatment for CMV retinitis includes highly active ART in HIV-positive patients, as well as antivirals targeting CMV such as ganciclovir, valganciclovir, foscarnet, cidofovir, or letermovir.

Port et al. discuss the epidemiology, clinical manifestations, current treatment, and complications of CMV retinitis.

Figure/Illustration A shows a right eye affected by CMV retinitis. The whitish perivascular lesions (blue box) and hemorrhagic necrosis (green arrow) are classic retinal findings in this condition.

Incorrect Answers:
Answer 1: Acyclovir can treat acute retinal necrosis (ARN), an inflammatory condition caused by either Varicella-Zoster Virus (VZV) or Herpes Simplex Virus (HSV-1 or HSV-2). ARN can present similarly to CMV retinitis, but usually involves the peripheral retina first, has less severe hemorrhage, and causes severe vitritis. In this patient with perifoveal lesions and more severe hemorrhage, CMV retinitis is more likely than ARN.

Answer 2: Famciclovir is a guanosine analog that inhibits viral DNA polymerase used to treat ARN, an inflammatory condition caused by either HSV or VZV. Famciclovir is specifically processed by HSV/VZV enzymes, so it has poor efficacy against CMV and would not be effective in this patient with CMV retinitis.

Answer 3: Oseltamivir inhibits neuraminidase and can be used to treat and prevent influenza A or influenza B. Oseltamivir decreases the risk of complications and reduces the length of hospitalization for influenza if given in the first 48 hours after the onset of symptoms. However, oseltamivir has no role in the treatment of CMV retinitis.

Answer 4: Sofosbuvir is a hepatitis C virus (HCV) RNA-dependent RNA polymerase (NS5B) inhibitor used to treat HCV. HCV has been associated with ischemic retinopathy in small case series. However, the evidence for this association is weak and this patient presents with CMV retinitis, making valganciclovir a better initial treatment choice.

Bullet Summary:
Cytomegalovirus (CMV) retinitis classically presents in immunosuppressed patients and can be treated with ganciclovir or valganciclovir.