HIV associated dementia
This is a common and serious complication of HIV infection, a form of dementia caused by brain damage related to the chronic presence of HIV infection. Unlike the majority of serious complications of HIV/Aids which are due to other infections taking advantage of the person's reduced immune responses, this seems to be a true effect of the HIV infection itself, though it can be complicated by other opportunistic infections such as drug toxicity, and malnutrition.
Also known as Aids dementia complex, ADC.
What is this condition?
It usually arises after years of HIV infection, but may be the first sign of the beginning of Aids itself, and is associated with low CD4* levels and high virus loads in the blood. It seems more common in Western countries (around 10 – 20% of cases) and less common in developing countries such as India (1 – 2 % prevalence is reported ). Whether this is related to diet or other life-style variations is not yet clear. It is also seen in paediatric Aids.
What causes this?
It is a disorder of brain structure and function caused by HIV infection and Aids. Cells in the brain infected with the virus secrete toxins which cause further nerve damage within the structure of the central nervous system.
What are the symptoms?
There is increasingly severe and disabling impairment of cognitive function, with poor concentration, memory problems, and slow thinking, apathy and weariness, with reduction in spontaneous activity and emotional response. Movement difficulties include clumsiness and loss of detailed control of one's muscles, trembling and bad balance.
How is it diagnosed?
By a careful medical history and an examination of mental functions, perhaps by means of some psychological testing. The existence of chronic HIV infection, along with typical impairment of mental function and the absence of other likely causes for such symptoms, is the usual basis for the diagnosis. Other tests may include a brain scan and Lumbar Puncture. It needs to be distinguished from other forms of brain disorder related to other infections occurring in someone with Aids, such as cytomegalovirus encephalitis/ infection. Generally multiple drugs would need to be used, with attention paid to the extent to which they can pass into the brain.
How is ADC treated?
The frequency of this disorder has dropped where proper antiretroviral therapy such as HAART has been used. It seems that such treatment might prevent or slow the onset of this disorder in people with HIV infections, and may also improve their condition and quality of mental function when ADC is already present.
When the degree of impairment is sufficiently severe to interfere seriously with daily functioning, such that the person is unable to work and may be unable to care for themselves, it is considered to be dementia.
What is the prognosis?
This is a serious complication of an HIV infection, and if left untreated it can be fatal, though the speed and nature of its progress is variable.
When to call your doctor
When a person with known chronic HIV infection starts to show symptoms of declining mental function, including forgetfulness.
How can it be prevented?
In the same way as we try to prevent HIV infection in the first place, and by careful use of appropriate anti-retroviral medicines when an HIV infection is present.
M. A. Simpson
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