AIDS Dementia Complex

AIDS dementia complex (ADC) is one of the most common neurological complications of late HIV infection. It causes the loss of mental function, affecting the ability to function in a social or occupational setting. more...

AIDS dementia complex (ADC) is characterized by cognitive dysfunction (trouble with concentration, memory and attention), declining motor performance (strength, dexterity, coordination) and behavioral changes. It occurs primarily in more advanced HIV infection when the CD4 cell counts are relatively low. Other terms for this condition are HIV-associated cognitive motor complex and HIV-associated dementia.

As many as 33% of adults and 50% of children with HIV experience AIDS dementia. Prior to the onset of HAART (Highly Active Anti-Retroviral Therapy), the incidences were much greater.

While the progression of dysfunction is variable, it is regarded as a serious complication and untreated can progress to a fatal outcome. Diagnosis is made by neurologists who carefully rule out alternative diagnoses. This routinely requires a careful neurological examination, brain scans (MRI or CT scan) and a lumbar puncture to evaluate the cerebrospinal fluid. No single test is available to confirm the diagnosis, but the constellation of history, laboratory findings, and examination reliably establish the diagnosis when performed by experienced clinicians. The amount of virus in the brain does not correlate well with the degree of dementia, suggesting that secondary mechanisms are also important in the manifestation of ADC.

AIDS Dementia Complex (ADC) is not a true opportunistic infection. It is one of the few conditions caused directly by the HIV virus. But it is not quite as simple as that because the central nervous system can be damaged by a number of other causes:

• opportunistic infections - there are many
• direct effects of HIV in the brain
• toxic effects of drug treatments
• malnutrition

Those with ADC have HIV-infected macrophages in the brain. That means HIV is actively infecting brain cells.

Symptoms of ADC include: Early - symptoms of AIDS Dementia can be confused with general manifestations of clinical depression. These include apathy, loss of interest in one's surroundings and the like. Later - symptoms involve cognitive and motor problems. Memory loss, as well as mobility problems, come into the picture.

Many researchers believe that HIV damages the vital brain cells, neurons, indirectly. According to one theory, HIV either infects or activates cells that nurture and maintain the brain, known as macrophages and microglia. These cells then produce toxins that can set off a series of reactions that instruct neurons to kill themselves. The infected macrophages and microglia also appear to produce additional factors chemokines and cytokines - that can affect neurons as well as other brain cells known as astrocytes. The affected astrocytes, which normally nurture and protect neurons, also may now end up harming neurons. Researchers hope that new drugs under investigation will interfere with the detrimental cycle and prevent neuron death.

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