Review Question - QID 107637

Patient with HIV and a CD4+ count less than 50 along with painless vision loss over a period of a few weeks is most likely suffering from cytomegalovirus (CMV) retinitis. He should be treated with valgancyclovir.

Cytomegalovirus (CMV) is a prevalent pathogen, with proposed infection rates 40 to 100%. CMV is a member of the Herpesviridae family, which includes the Epstein-Barr virus (EBV), herpes simplex virus, varicellazoster virus, and herpesvirus 6, 7, and 8. Like those viruses, infection with CMV is lifelong with the virus remaining latent within the host and reactivating when the immune system is compromised (such as in HIV, organ transplant, chemotherapy). It is especially dangerous in the immunocompromised and pregnant women as congenital infection can often be fatal.

Taylor discusses CMV and its role in HIV patients. Taylor states that before HAART therapy, CMV retinitis was the second most common opportunistic infection in HIV patients and that 21 to 45% of the patients presented with complications of CMV retinitis, an irreversible form of vision loss. They also recommend that an ophthalmologist should do a dilated indirect funduscopic examination on patients with symptoms or a CD4 count of less than 50 per mm3 every three to four months because only 10 percent of the retinal area can be observed with the use of a direct ophthalmoscope.

Jabs et al. compared different treatment regimens for CMV retinitis. When they compared intraocular only regimens with systemic therapy, they found that regimens containing systemic anti-CMV therapy were associated with a 50% reduction in mortality, a 90% reduction in new visceral CMV disease, and an 80% reduction in second eye disease (among those who only presented with uniocular disease) (P<0.01).

Figure A shows yellow-white patches of retinal opacification due to CMV retinitis. Illustration A shows widespread retinal hemorrhage with dilated retinal blood vessels.Illustration B shows a detached superior retina.

Incorrect Answers:
Answer 1: Retinal vein occlusion would present with painless vision loss, but would have dilated veins along with hemorrhage on fundoscopic exam. (Illustration A)
Answer 2: Retinal detachment would present with painless vision loss in the setting of hypertension or trauma, but would have a detached retina along with the patient complaining of "floaters" or "flashes." It may also present with a dark curtain falling over the eye if the detachment is severe as illustrated. (Illustration B)
Answer 3: Acute angle closure glaucoma would present with severe pain, increased intraocular pressure, and a mid-dilated pupil.
Answer 5: HSV retinitis would present in a patient with a low CD4+ count (as above) , but would present with painful vision loss instead of painless vision loss. HSV also may involve other parts of the eye such as the retina.