HIV-associated dementia

Walter Royal III MD (Dr. Royal of the University of Maryland School of Medicine has no relevant financial relationships to disclose.)
Diana L Vargas MD (Dr. Vargas of the University of Maryland School of Medicine has no relevant financial relationships to disclose.)
Richard T Johnson MD, editor. (Dr. Johnson of the Johns Hopkins University School of Medicine and Bloomberg School of Public Health has no relevant financial relationships to disclose.)
Originally released April 1, 1994; last updated April 24, 2014; expires April 24, 2017

This article includes discussion of HIV-associated dementia, AIDS dementia complex, HIV encephalopathy, HIV-associated dementia complex, AIDS-related dementia, and HIV dementia. The foregoing terms may include synonyms, similar disorders, variations in usage, and abbreviations.

Key points

 

• HIV-associated dementia is, untreated, a progressive clinical syndrome that occurs as a primary manifestation of HIV infection.

 

• The prevalence of the disorder has increased with the introduction of effective antiretroviral combination therapies and increased survival of infected individuals.

 

• Recently recommended approaches for diagnosis allow for the categorization of individuals as having impairment that can range from mild to very severe, which has prognostic implications.

 

• Effective control of the progression of neurocognitive impairment is linked to success in treating the underlying HIV-1 infection and in managing symptoms using currently available drug therapies.

Historical note and terminology

The term “HIV-associated dementia” refers to a characteristic progressive encephalopathy that results from HIV-1-related impairment of normal brain function. The disorder makes up part of a spectrum of cognitive impairments caused by HIV infection in the CNS named “HIV-associated neurocognitive disorders.” The disorder occurs in the absence of detectable primary effects from other pathogens or conditions. HIV-associated dementia was originally termed "subacute encephalitis" (Snider et al 1983). Navia and Price subsequently introduced the term "AIDS dementia complex" (Navia and Price 1987), which refers to the fact that the motor deficits and myelopathy occur frequently in association with AIDS dementia. The term "HIV encephalopathy" was added to the list of those used to refer to AIDS dementia (Levy and Bredesen 1988), and in 1991, the American Academy of Neurology AIDS Task Force developed definitional criteria for AIDS dementia (Janssen et al 1991). The terms "AIDS dementia complex," "HIV dementia," and "HIV encephalopathy," and the most recent term, "HIV-1-associated cognitive/motor complex," which was introduced by recommendation of the American Academy of Neurology task force, are synonymous. Before antiretroviral therapy was available, 20% to 30% of patients with severe HIV disease had HIV-associated dementia (Gonzalez-Scarano and Martin-Garcia 2005; Kaul and Lipton 2005). With the introduction of highly active antiretroviral therapy, the incidence of HIV-associated dementia has decreased, but given the increase in life expectancy of HIV-positive individuals, the prevalence of HIV-associated dementia is increasing. It is thought that about 40% of HIV-infected patients have some form of HIV-associated neurocognitive disorders (Sacktor et al 2001; Sacktor 2002; McArthur 2004; Antinori et al 2007).

As part of the HIV-associated neurocognitive disorders, minor cognitive motor disorders, HIV-associated mild neurocognitive disorders, and asymptomatic neurocognitive impairment are all milder forms of cognitive and motor impairment that are not yet sufficient enough to receive the diagnosis of dementia. These milder forms of HIV-associated neurocognitive disorders have a persistently high prevalence and suggest a shift in HIV-associated neurocognitive disorders subtypes in the posttreatment era (Sacktor 2004). At this time, it appears that this minor impairment progresses to frank dementia in only a relatively small subset of individuals. In some cases, the disorders may be associated with poor performance on neuropsychological tests among individuals with a history of substance use, advanced age, or prior traumatic head injury, or due to educational factors (Hestad et al 1995; Concha et al 1997). Although only a small subset of patients may progress to frank dementia, even patients with the mildest of symptoms can have their quality of life affected by disruptions in their ability to perform and, most importantly, adhere to their medication regimens (McArthur 2004).

The term "HIV encephalitis" should be reserved for the pathological features of multinucleated giant cell encephalitis with HIV identified in the brain and not used to describe the clinical syndrome. Similarly, although HIV-associated dementia complex can develop concurrently with other HIV-associated neurologic disorders, such as myelopathy and neuropathy, it appears that the spinal cord and peripheral nerve diseases are discrete disorders with distinct manifestations, courses, and pathogenetic mechanisms.

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