AIDS Dementia Complex

Definition

Definition of AIDS Dementia Complex
AIDS dementia complex (ADC; also known as HIV dementia, HIV encephalopathy, HIV-associated dementia and HIV-associated neurocognitive disorder) is a common neurological disorder associated with HIV infection and AIDS. It is a metabolic encephalopathy induced by HIV infection and fueled by immune activation of macrophages and microglia. These cells are actively infected with HIV and secrete neurotoxins of both host and viral origin. The essential features of ADC are disabling cognitive impairment accompanied by motor dysfunction, speech problems and behavioral change. Cognitive impairment is characterised by mental slowness, trouble with memory and poor concentration. Motor symptoms include a loss of fine motor control leading to clumsiness, poor balance and tremors. Behavioral changes may include apathy, lethargy and diminished emotional responses and spontaneity. Histopathologically, it is identified by the infiltration of monocytes and macrophages into the central nervous system (CNS), gliosis, pallor of myelin sheaths, abnormalities of dendritic processes and neuronal loss.

Symptoms

Symptoms of AIDS Dementia Complex
Although the severity and relative prominence of some symptoms and signs compared to others may vary among individual patients, the general character of ADC involves three functional categories: cognition, motor performance, and behavior. Table 2 provides an outline of some of the early and late manifestations. Of the three categories, cognitive and motor dysfunction are the most helpful in characterizing patients and in defining diagnosis; it is for this reason that they provide the basis of ADC Staging, which omits behavioral criteria. When approaching diagnosis, it is useful to separately consider milder and more severe affliction.

Research

Research of AIDS Dementia Complex
AIDS Dementia Complex (ADC) is not a true opportunistic infection; it is one of the few conditions caused directly by HIV itself. However, the etiology of ADC can be difficult to discern because the central nervous system can be damaged by a number of other causes related to HIV infection:

1. opportunistic infection
2. primary cerebral lymphoma or metastasis of other AIDS-related cancers
3. direct effects of HIV in the brain
4. toxic effects of drug treatments
5. malnutrition

Diagnosis

Diagnosis of AIDS Dementia Complex

1. Marked acquired impairment of at least two ability domains of cognitive function (e.g. memory, attention): typically, the impairment is in multiple domains, especially in learning, information processing and concentration/attention. The cognitive impairment is ascertained by medical history, mental status examination or neuropsychological testing.
2. Cognitive impairments identified in 1. interfere markedly with day-to-day functioning.
3. Cognitive impairments identified in 1. are present for at least one month.
4. Cognitive impairments identified in 1. do not meet the criteria for delirium, or if delirium is present, dementia was diagnosed when delirium was not present.
5. No evidence of another, pre-existing aetiology that could explain the dementia (e.g. another CNS infection, CNS neoplasm, cerebrovascular disease, pre-existing neurological disease, severe substance abuse compatible with CNS disorder.

Treatment

Treatment of AIDS Dementia Complex
Strategies to treat ADC have followed the guidelines suggested by concepts of pathogenesis. Thus, if brain injury results from the linking of brain infection to endogenous cytokine-linked neuropathic processes, then treatment efforts might attempt to interrupt these processes at various vulnerable points. The most effective approach involves antiretroviral therapy, because HIV infection seems to be the prime-mover of ADC pathogenesis.

Unfortunately, the optimum regimen for ADC is not established, largely because this issue has not yet been addressed with respect to contemporary combination therapy. In fact, evidence of antiviral efficacy derives principally from the experience with zidovudine monotherapy, which has been shown in a number of adult and pediatric studies to prevent and reverse clinically symptomatic ADC and also to reduce the incidence of brain infection. One therefore needs to extrapolate from these data, which demonstrate that zidovudine monotherapy is helpful, to the suggestion that combination therapy likely would be even more effective, as it is in systemic HIV-1 infection. This conclusion seems reasonable even if not directly proven or supported by controlled observations.

Prevention

Prevention of AIDS Dementia Complex
Consult with your doctor.