COMANAGEMENT Q&A

Comanaging CMV Retinitis

Edited by Paul C. Ajamian, O.D.

Question:  What are the characteristic signs of CMV retinitis?

Answer:  CMV retinitis is the most common ocular infection in AIDS patients. Untreated, it results in blindness. The disease manifests late in the AIDS process, after drug therapy has failed. Arresting CMV retinitis is crucial in extending a patient's life span.

In the early stages, patients can be asymptomatic. Early fundus signs can include cotton wool spots, a precursor of the onset of CMV retinitis. Later signs in-clude flashes, floaters, field loss or blurred vision that develop over several days or weeks. A dilated fundus exam might show peri-vascular exudate with granular border, hemorrhage, optic neuritis, macular edema, and some vitritis, says Robert Kalayjian, M.D., infectious disease specialist at Case Western Reserve University in Cleveland. Retinal detachment might also be present, a risk that increases with the duration of the disease.

CMV retinitis doesn't necessarily result in immediate vision loss. Explains Dr. Kalayjian: "Visual field loss occurs when the disease presents in the periphery. Progres-sion of the disease into the macula or optic nerve will cause loss of central vision." The disease usually presents unilaterally, but it can affect the fellow eye and other organs if not controlled.

Question:  What therapies are available, and how would you comanage the disease?

Answer:  Current antiviral therapies include ganciclovir, foscarnet, or cidofovir. They are delivered either systemically through a central intravenous line or locally through an intravitreal implant. "Occasionally, doctors will inject the drug directly into the retina, but that approach is usually reserved for patients who can't tolerate systemic treatments or the implant," Dr. Kalayjian says. After an initial therapeutic regimen of about two weeks, patients typically transfer to maintenance therapy.

The intravitreal implant, which releases a sustained amount of ganciclovir over eight months, is the most potent delivery method available today and less toxic than either I.V. or oral treatment, Dr. Kalay-jian says.

Because it doesn't require a central I.V. line, it enhances a patient's lifestyle and eliminates the possibility of I.V. site infections. Implant patients have a 5 percent greater incidence of retinal detachment, most likely from the surgery.

To prevent systemic disease progression in an implant patient, supplement with oral antivirals. Be aware, however, that the eye does not absorb oral drugs as well as it does implant drugs. Both oral and I.V. systemic treatments may cause neutropenia, and foscarnet and cidofovir can cause renal toxicity.

In deciding which treatment is best, you and the medical doctor managing the disease must consider the following: access to retinal surgical expertise, the ability of the patient to take oral antivirals, the potential for I.V. site infections and the patient's ability to tolerate drug toxicity.

Monitor the patient closely every two to four weeks until the disease resolves, advises Sherry Bass, O.D., professor at the State University of New York State College of Optom-etry. "At each visit, perform a dilated fundus exam and take photos," she says. Look for signs of detachment; macular, retinal or optic disc edema or hemorrhage; or for the re-appearance of white retinitis lesions. Vitritis, vasculitis or uveitis might be present, though some patients aren't able to produce an inflammatory response due to their low T-cell count. Check visual acuity, too, she advises.

Communicate your findings to the medical doctor after every visit so that he or she can make appropriate adjustments in medication.

Once the disease resolves, you can reduce visits to every three to six months, but perform the same exam regimen each time, and always report your findings to the physician.