Review Question - QID 106557

This immunocompromised patient is presenting with CMV retinitis. Ganciclovir is an antiviral that treats CMV infections.

CMV, a human herpes virus, is a linear, dsDNA enveloped virus that is transmitted via the following routes: congenital, blood transfusion, sex, saliva, urine, and transplants. Once CMV has established its initial infection, it establishes a latent infection within mononuclear cells. CMV causes EBV-negative mononucleosis in immunocompentent individuals. In infants, it causes cytomegalic inclusion disease resulting in neonatal jaundice, hepatosplenomegaly, thrombocytic purpura, hearing loss, and seizures. In the immunocompromised individuals, it causes CMV retinitis and pneumonia. Treatment options include foscarnet or ganciclovir. Ganciclovir, a guanosine analog, functions by acting as a viral DNA polymerase inhibitor. Side effects include leukopenia, thrombocytopenia, neutropenia, and nephrotoxicity.

Figure A demonstrates cotton-wool spots on the retina in CMV retinitis, which appear as white patches on the retina and are caused by neuronal damage. Illustration A shows the classic CMV inclusion body which is intranuclear and is surrounded by a clear halo.

Incorrect Answers:
Answer 1: Amantadine is an antiviral that blocks viral attachment, penetration, or uncoating. It is used to treat influenza A.
Answer 2: Ribavarin is a guanosine analog that acts as a viral RNA polymerase inhibitor and an inhibitor of IMP dehydrogenase thereby inhibiting the production of guanine nucleotides. It is used to treat chronic hepatitis C and RSV.
Answer 3: Flucytosine is an antifungal that blocks pyrimidine synthesis by conversion to 5-fluorouracil, which in turn inhibits fungal cytosine deaminase. This ultimately leads to DNA synthesis inhibition. It is used to treat cryptococcal and candidal infections.
Answer 4: Nystatin is an antifungal that binds to ergosterol, subsequently forming pores in the fungal membrane and leading to potassium leakage, acidification, and fungal death. It is used to treat candidiasis.