American Board of Psychiatry and Neurology (ABPN) Practice Exam

What is the most common infectious agent linked to decreased visual acuity in an AIDS patient?

1. Cytomegalovirus

2. Toxoplasmosis

3. Cryptococcus neoformans

4. JC virus

The correct answer is: Cytomegalovirus

Cytomegalovirus (CMV) is indeed the most common infectious agent associated with decreased visual acuity in patients with AIDS. CMV retinitis is a leading cause of vision loss among individuals with advanced HIV infection due to their immunocompromised state. The virus can cause retinal inflammation and damage, leading to significant visual impairment. Patients with AIDS are particularly susceptible to opportunistic infections due to their weakened immune systems. CMV often reactivates in these individuals, leading to a clinical presentation that can include symptoms such as floaters, flashes of light, or even blind spots. In advanced cases, it can result in significant visual loss if not treated promptly with antiviral medications. Other infectious agents listed, such as Toxoplasmosis and Cryptococcus neoformans, although associated with various complications in AIDS, do not primarily lead to visual acuity decline as prominently as CMV does. Toxoplasmosis typically affects the central nervous system and can lead to neurological deficits rather than direct visual acuity issues. Cryptococcus neoformans mainly causes meningitis and presents with neurological symptoms rather than directly impairing eyesight. The JC virus is associated with progressive multifocal leukoencephalopathy, affecting cognitive function and motor skills rather than vision.