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November 2001
Diagnosis: This patient has cytomegalovirus (CMV) retinitis.
CMV is a common viral infection. Most immunocompetent individuals who are infected with CMV are either asymptomatic or develop a mononucleosis-like syndrome. In the immunocompromised host, CMV is the most common cause of retinitis, affecting 25-40 percent of adult patients with AIDS. Retinitis is a marker for systemic disease. The risk for CMV retinitis increases with a declining CD4+ lymphocyte count with the greatest risk occurring at a CD4+ lymphocyte count less than 50/uL.
Adults with CMV retinitis present with early symptoms such as floaters, a decrease in central vision, or visual field loss. In children with HIV infection, CMV retinitis is the most common cause of blindness. While the incidence of CMV retinitis is lower in children than in adults, the severity of disease is often worse at presentation. Children rarely complain of symptoms until their visual acuity is adversely affected, a late manifestation of the disease.
Diagnosis of CMV retinitis relies on funduscopic examination of the dilated pupil by an experienced ophthalmologist. Retinal examination shows large, yellow to white areas with perivascular exudates and hemorrhages. Retinal exam may also reveal a white granular lesion border and mild intraocular inflammation. Serologic tests can be performed, however the utility of the results is limited given the high prevalence of positive antibody titers in asymptomatic individuals.
Currently, there are three antiviral agents used for treatment of CMV retinitis. Parenteral ganciclovir, foscarnet, and cidofovir are all approved for treatment of CMV retinitis. However, there have been no large, randomized studies in children. Because children often present with sight-threatening disease, an aggressive multi-drug approach with ganciclovir and foscarnet has been used. Intraocular implants of ganciclovir have also been developed. However, they must be used with concomitant parenteral or oral antiviral agents to prevent the development of symptoms systemically or in the contralateral eye. The ganciclovir implants are of limited use in children younger than 3 years of age secondary to the size of the eye. It is important to note that these antiviral agents do not eradicate CMV. As such, maintenance therapy with one of the above antiviral agents is necessary to prevent recurrence of the retinitis or the development of systemic symptoms. Individuals receiving highly active antiretroviral therapy in whom the CD4+ lymphocyte count increases above 50/uL may have the option of discontinuing maintenance therapy. The patient should continue to have close follow up with an ophthalmologist.
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