Cognitive disorder in the setting of HIV infection was recognized a long time ago and was referred to with various names. The term AIDS dementia complex was introduced by Navia and colleagues in 1986.
Human immunodeficiency virus (HIV) enters the central nervous system (CNS) early in the course of the infection and causes several important CNS conditions over the course of the disease, such as HIV encephalopathy and AIDS dementia complex.
As part of the acute HIV syndrome during seroconversion, patients may experience HIV encephalopathy. HIV-associated progressive encephalopathy (HPE) is a syndrome complex with cognitive, motor, and behavioral features seen in children.
Prior to the advent of highly active antiretroviral therapy (HAART), dementia was a common source of morbidity and mortality in HIV-infected patients. It was usually observed in the late stages of acquired immunodeficiency syndrome (AIDS), when CD4+ lymphocyte counts fall below 200 cells/mL, and was seen in up to 50% of patients prior to their deaths.
In 1986, the term AIDS dementia complex (ADC) was introduced to describe a unique constellation of neurobehavioral findings.
HIV associated neurocognitive disorder (HAND) encompass a hierarchy of progressively more severe patterns of neurological involvement. It can range from asymptomatic neurocognitive impairment (ANI) to minor neurocognitive disorder (MND) to more severe HIV-associated dementia (HAD) (also called AIDS dementia complex [ADC] or HIV encephalopathy).
ADC is considered a single entity with a broad and varied spectrum of clinical manifestations and severity.
ADC is characterized by cognitive, motor, and behavioral features in adults, usually those with advanced AIDS. With the advent of HAART, a less severe dysfunction, minor cognitive motor disorder (MCMD), has become more common than ADC.
The overall psychosocial and emotional burden on the family and friends of patients with HIV dementia is tremendous, far beyond that of a cognitively intact patient with AIDS. Patients with cognitive difficulties have problems with compliance and adherence to their medication regimen. Because of their neuropsychiatric problems, these patients are likely to be less inhibited and are more prone to HIV-related risk behavior (eg, unprotected intercourse), and they therefore pose a greater risk of transmission of the virus.
In addition to HIV itself, other causes of neurologic complications in HIV-infected individuals include opportunistic infections, tumors, and antiretroviral drugs. Other neurologic complications that arise from primary HIV infection include vacuolar myelopathy, peripheral neuropathies, and polymyositis.