Controversies in HIV-associated neurocognitive disorders

Abstract

Cross-sectional studies show that around half of individuals infected with HIV-1 have some degree of cognitive impairment despite the use of antiretroviral drugs. However, prevalence estimates vary depending on the population and methods used to assess cognitive impairment. Whether asymptomatic patients would benefit from routine screening for cognitive difficulties is unclear and the appropriate screening method and subsequent management is the subject of debate. In some patients, HIV-1 RNA can be found at higher concentrations in CSF than in blood, which potentially results from the poor distribution of antiretroviral drugs into the CNS. However, the clinical relevance of so-called CSF viral escape is not well understood. The extent to which antiretroviral drug distribution and toxicity in the CNS affect clinical decision making is also debated.

Figure 1

Changes in the prevalence of HIV-associated neurocognitive disorder in the USA before (HNRC study, N=678) and after (CHARTER study, N=843) the widespread use of HAART ANI=asymptomatic neurocognitive impairment. MND=mild neurocognitive impairment. HAD=HIV-associated dementia. HAART=highly active antiretroviral therapy

Figure 2

Overview of proposed pathological mechanisms underlying HIV-associated neurocognitive disorders

Figure 3

Summary of the Frascati criteria for HIV-associated neurocognitive disorders