CMV Retinitis Clinical Presentation

Updated: Oct 20, 2016
  • Author: Michael Altaweel, MD, FRCSC; Chief Editor: Hampton Roy, Sr, MD  more...
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Presentation

History

Presenting symptoms vary depending on the location of retinal involvement. Posterior lesions present with diminished visual acuity. More peripheral lesions initially can be asymptomatic. Floaters often are noted if significant vitreitis is present. The eye usually is white and quiet.

Active CMV retinitis usually is found in conjunction with immunosuppression, whether from AIDS, leukemia, or use of chemotherapy. These points are important in evaluating the patient history. Rarely, CMV retinitis is the first presenting manifestation of AIDS.

After initiation of therapy, some advance of the leading edge of retinitis may be noted. This usually is not a treatment failure but rather the revealing of an area of subclinical infection that was not previously evident.

Natural history

CMV retinitis is a slowly progressive disease, requiring weeks to months to involve the entire retina. [29, 30] Vision is lost with involvement of the posterior pole (macula or optic nerve) or retinal detachment. [31]

Initial reports described CMV retinitis as an end-stage disease, which indicated a life expectancy of 6 weeks. With the use of antiviral medications, the average survival after diagnosis ranged from 5.5-8 months. The advent of HAART has prolonged survival to years in some instances, and it has allowed discontinuation of medications targeted against CMV retinitis if clinical resolution occurs and the immune status recovers (reflected by a CD4 count of >100 cells/μL).

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Physical

Patients with suspected CMV retinitis should have a complete ocular examination of both eyes. A careful examination should include the following.

Carefully check and record the patient's best corrected visual acuity as a baseline. Check for visual field defects that could represent optic nerve damage, retinal detachment (RD), or CNS disease from AIDS-related brain diseases (eg, encephalitis, stroke, CNS lymphoma). [32, 33] Ocular motility should be assessed as part of a cranial nerve examination. Pupils should be checked for a relative afferent pupillary defect indicating optic nerve involvement.

External examination of the lids and adnexa should be performed for other AIDS-associated findings, such as Kaposi sarcoma or lymphoma.

A thorough slit lamp examination should show a white and quiet conjunctiva. A red hot eye in an immunocompromised patient should alert the clinician to another possible diagnosis. Fine, stellate keratitic precipitates (KP) characteristic of CMV may be seen on the corneal endothelium. [34] Uveitis may be present in the anterior chamber and, if severe, may require treatment. The level of vitreitis can be assessed in the anterior vitreous and may be important for monitoring response to treatment or the occurrence of IRU.

A dilated fundus examination with indirect ophthalmoscopy is essential for assessing the location and extent of retinal involvement as well as for evaluating for retinal breaks or detachment. Retinal lesions have several characteristics, [35, 36] as follows:

  • Initial examination typically reveals 1 or 2 foci of disease. Multifocal disease at time of presentation is uncommon.
  • Most early lesions occur in a perivascular distribution, likely reflecting the hematogenous spread of the virus.
  • Lesions that present posteriorly appear along retinal vessels as large areas of thick white infiltrate accompanied by retinal hemorrhage described as "pizza pie" or "cheese pizza" in appearance.
  • The peripheral type of lesion demonstrates a more granular appearance with satellite lesions and less hemorrhage. Behind the advancing border is necrotic retina with mottled pigmentation from hyperplasia of the retinal pigment epithelium (RPE).
  • Lesions usually begin peripherally and spread posteriorly in a contiguous fashion (see image below). However, multiple unconnected lesions are frequent, and involvement of the posterior pole with minimal peripheral disease is possible (5-10%).
    Retinitis typically starts in the midperiphery and Retinitis typically starts in the midperiphery and can progress in a "brush fire" pattern.
  • Retinitis follows the nerve fiber layer.
  • Retinitis produces wide areas of necrosis, scarring, and atrophy (see image below).
    Early necrosis at periphery. Early necrosis at periphery.
  • Even severe retinitis is usually accompanied by minimal vitreitis in the immunocompromised patient. If HAART is instituted and immune reconstitution occurs, then IRU with severe anterior and posterior uveitis may occur.
  • Extensive vascular sheathing, often described as frosted branch angiitis, is a known but uncommon appearance (see image below). [37, 38]
    Frosted branch angiitis. Frosted branch angiitis.
  • Retinal vascular occlusion/nonperfusion can be seen on fluorescein angiogram. [39]

Peripheral holes and tears frequently occur in areas of necrosis (see image below).

Retinal detachment due to peripheral tear in area Retinal detachment due to peripheral tear in area of necrosis.

Rate of progression of untreated retinitis is 250-350 µm per week. Skip lesions can occur.

Serial examinations may be necessary at early stages to distinguish CMV retinitis from HIV retinopathy with multiple cotton-wool spots.

Optic neuritis can develop without apparent retinitis. [40]

Most patients with CMV retinitis will initially present with unilateral disease. Untreated, the immunocompromised patient has a 50% risk of developing disease in the contralateral eye within 6 months. [41, 42] This is reduced to 20% with antiviral treatment and further reduced with HAART.

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Causes

Any immunosuppression due to disease or medication may allow clinical CMV infection to develop, as follows:

  • Acquired immune deficiency syndrome [43]
  • Leukemia, lymphoma, and aplastic anemia [44]
  • Use of immunosuppressive chemotherapy
  • Organ, bone marrow, and stem cell transplant recipients [4]

Congenital CMV retinitis is acquired from vertical transmission during pregnancy. When primary maternal infection occurs during pregnancy, the risk of transmission to the fetus ranges between 30% and 40%. Transmission during the first half of pregnancy generally causes more severe disease.

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