From the Guidelines
HIV encephalopathy is characterized by a predominantly subcortical cognitive–motor syndrome, also known as HIV-associated dementia, which is an AIDS-defining condition, with key features including impaired concentration, memory deficits, slowed thinking, and difficulty with complex tasks, as described in the 2023 study published in Nature Reviews Neurology 1. The condition typically develops gradually, with subtle cognitive changes that worsen over time, and neuroimaging may show brain atrophy, white matter abnormalities, and ventricular enlargement. Some of the key features of HIV encephalopathy include:
- Impaired concentration and memory deficits
- Slowed thinking and difficulty with complex tasks
- Motor symptoms such as poor coordination, unsteady gait, and tremors
- Behavioral changes, including apathy, social withdrawal, personality alterations, and in advanced cases, psychosis HIV encephalopathy results from direct viral infection of the central nervous system, with HIV-infected macrophages and microglia releasing neurotoxic viral proteins and inflammatory mediators that damage neurons, as discussed in the 2009 study published in Antiviral Research 1. The most effective treatment for HIV encephalopathy is early initiation of antiretroviral therapy (ART), which reduces viral replication in the brain and can improve or stabilize neurological symptoms, as recommended in the 2023 study published in Nature Reviews Neurology 1. The regimen should include medications with good CNS penetration, such as dolutegravir, darunavir, or efavirenz, and adjunctive treatments may include antidepressants for mood symptoms and physical therapy for motor deficits. Regular neuropsychological assessment is important to monitor disease progression and treatment response, and to distinguish between HIV-associated brain injury (HABI) and other causes of cognitive impairment, as proposed in the 2023 study published in Nature Reviews Neurology 1.
From the Research
Features of HIV Encephalopathy
The features of Human Immunodeficiency Virus (HIV) encephalopathy include:
- Cognitive impairment, such as attentional disorder, executive function deficit, memory and concentration deficits 2, 3
- Motor dysfunction, including psychomotor slowing, impaired speech, gait, and coordination, and psychomotor retardation 3, 4
- Personality and behavioral disturbances, decreased memory, inability to concentrate, and apathy 4
- Global impairment of intellectual and cognitive functions 4
- Subcortical dementia, characterized by psychomotor slowing, as well as memory and concentration deficits 3
- Deficits of central motor function, including impaired speech, gait, and coordination 3
Neuropathological Features
The neuropathological features of HIV encephalopathy include:
- Generalized cortical atrophy, resulting in the death of multiple classes of neurons 5
- Neurotoxic effects elicited directly by viral products, as well as indirectly by the immune response to the virus 3
- Enhanced viral replication in immunocompetent CNS cells, leading to neurotoxic effects 3
- Action of HIV-associated proteins, such as Tat and gp120, which bear responsibility for many of the neuropathologies associated with HIV-associated dementia (HAD) and HIV-associated neurocognitive disorder (HAND) 5
Diagnosis and Prevalence
HIV-associated neurocognitive disorder (HAND) affects roughly half the HIV-positive population, with symptoms of cognitive slowing, poor concentration, and memory problems 6. The diagnosis of HAND is validated by identifying deficits in two cognitive domains on neuropsychologic testing, and corroborating evidence may be found on imaging, blood tests, and cerebrospinal fluid analysis 6.