The management of cytomegalovirus retinitis in AIDS.

Cytomegalovirus (CMV) shares many properties with other members of the herpesvirus family it exhibits latency, reactivates under suitable conditions to cause human disease, and it is incurable. CMV is the primary opportunistic viral infection in the immunosuppressed person and gives rise to a wide spectrum of disease. CMV is a major cause ofmorbidity and mortality among patients with AIDS, and the retina is the commonest site of infection.' Cytomegalovirus retinitis (CMVR) may be the AIDS defining diagnosis though more commonly occurs months after the diagnosis of AIDS. If left untreated, patients with unilateral CMVR are likely to develop disease in their second eye and ultimately become blind.2 It has now become accepted practice to treat sight threatening CMVR with either ganciclovir or foscarnet, which are effective in delaying the progress ofthis destructive infection. Systemic treatment for CMV disease also reduces extraretinal CMV related morbidity and mortality and subjectively improves quality of life.3 This review of the clinical management ofCMVR in patients with AIDS also includes complications of therapy, and dilemmas which face the patient, physician, and ophthalmologist. The use of antiretroviral agents together with the early recognition and treatment of opportunistic infection has led to the increased survival of patients with AIDS despite their profound immunodepletion. The median survival of patients with AIDS after the diagnosis of CMV disease is 1 year or longer,'4 and, as with other evolving statistics concerning CMVR, this is likely to underestimate the current clinical experience.' Given the increasing number of patients with HIV infection, and their longer survival, it is likely that CMVR will become an increasingly prevalent condition. A previous communication reported the increasing CMVR attack rate with prolonged survival,6 and supports the impression that the majority of patients with AIDS would develop CMVR if they survived long enough. Reports from the United States ofCMVR prevalence ofup to 40% among patients with AIDS2378 vary widely due to differences in patient recruitment, detection method, and populations studied. Geographical variations in survival which relate to the availability and use of drugs to treat opportunistic infections would also influence the prevalence of CMVR. Studies carried out prospectively or post mortem would yield the most accurate prevalence data. Regional series from London and Edinburgh estimated the minimum risk of developing sight threatening CMVR among patients with AIDS as 17%,' despite differences between the two populations in terms of HIV transmission group. In Edinburgh 38% of AIDS is associated with homosexual/ bisexual behaviour, though this percentage constituted 75% of patients with CMVR in this region; this is probably a reflection of the higher prevalence of sexually acquired CMV infection. It could also represent greater immunosuppression in the homo/bisexual group because of the longer duration of infection.6 In this region CMVR is the index diagnosis in approximately 3% ofpatients with AIDS and 17% ofpatients with CMVR and AIDS. Symptoms In comparison with the more severe systemic symptoms associated with AIDS the onset ofCMVR is associated with few visual symptoms; unless the patient is aware of their significance, relatively minor visual symptoms may be considered too trivial to disclose to his physician. In Edinburgh from a cohort of 24 patients with CMVR and AIDS, 16 had unilateral retinitis at presentation and, although 59% of this group had macula and/or optic nerve threatening disease, less than half the group showed visual symptoms.9 Visual blurring, photopsia, floaters, and scotomata are usually only noticed on occlusion of the unaffected eye, or when CMVR affects both eyes. Although untreated CMVR is relentlessly progressive, the spread is relatively slow, and may partly explain the absence of acute visual symptoms. The size and location of CMVR iifluence the rate of progression.'0 The insidious and silently progressive nature of CMVR may result in advanced disease before symptoms become apparent, resulting in delayed diagnosis and treatment.