AIDS Health Article

Neurological complications of AIDS

Almost 30% of people with AIDS develop peripheral neuropathy, causing tingling, numbness, and weakness in the arms and legs due to nerve damage. If severe, peripheral neuropathy can cause difficulty walking. Several drugs used to treat people with AIDS can contribute to the development of peripheral neuropathy.

Several opportunistic infections experienced by people with AIDS involve the nervous system. Progressive multifocal leucoencephalopathy (PML) is a serious viral infection of the brain, most often caused by the JC virus. PML is fatal in more than 90% of cases within six months of diagnosis. Nearly 4% of people with AIDS, especially those with T-cell counts below 100, will develop the disease. Meningitis is an infection of the lining of the spinal cord and brain, and also occurs in some people with AIDS. Cryptococcus, a fungus that normally occurs in the soil and seldom affects persons with intact immune systems, can cause recurring meningitis in people with AIDS whose T-cell count is below 100. The common parasite Toxoplasma gondii often present in cat feces, raw meat, raw vegetables, and the soil can also cause encephalitis, or inflammation of the brain, in AIDS patients. Shingles is a painful nerve inflammation caused by a reactivation of the herpes varicella zoster virus, the same virus that causes chicken pox. Although not directly linked to HIV, shingles seems to occur more frequently in people with AIDS.

Other neurological conditions associated with AIDS include depression, occurring at any time during the disease, and dementia, which sometimes occurs in the later stages of AIDS. Depression can stem from living with a chronic and progressive disease. AIDS-related dementia involves problems with thinking, memory, and usually also with controlling the arms and legs, and can stem from direct infection in the brain with the HIV virus. In the initial stages of the pandemic, almost 20% of persons with AIDS developed severe dementia. With the development of combination antiviral drugs, the rate of severe dementia in AIDS has been reduced by more than half. The number of persons with HIV and milder dementia has increased, however, as people with HIV live longer.

Diagnosis

In the early stages of infection, HIV often causes no symptoms and the infection can be diagnosed only by testing a person's blood. Two tests are available to diagnose HIV infection, one that looks for the presence of antibodies produced by the body in response to HIV and the other that looks for the virus itself. Antibodies are proteins produced by the body whenever a disease threatens it. When the body is infected with HIV, it produces antibodies specific to HIV. The first test, called ELISA (enzyme-linked immunosorbent assay), looks for such antibodies in the blood.

A positive ELISA has to be confirmed by another test called western blot or immunofluorescent assay (IFA). All positive tests by ELISA are not accurate and hence, western blot and repeated tests are necessary to confirm a person's HIV status. A person infected with HIV is termed HIV positive or seropositive.

Rapid tests that give results in five to 30 minutes are increasingly being used worldwide. The accuracy of rapid tests is stated to be as good as that of ELISA. Though rapid tests are more expensive, researchers have found them to be more cost effective in terms of the number of people covered and the time the tests take.

The HIV antibodies generally do not reach detectable levels in the blood until about three months after infection. This period, from the time of infection until the blood is tested positive for antibodies, is called the window period. Sometimes, the antibodies might take up to six months to be detected. Even if the tests are negative, during the window period the amount of virus is very high in an infected person. If a person is newly infected, therefore, the risk of transmission is higher.

Another test for HIV is called polymerase chain reaction (PCR), which looks for HIV itself in the blood. This test, which recognizes the presence of the virus' genetic material in the blood, can detect the virus within a few days of infection. There are also tests like radio immuno precipitation assay (RIPA), a confirmatory blood test that may be used when antibody levels are difficult to detect or when western blot test results are uncertain.

Treatment team

The treatment team often includes personal care-givers, physical therapists, dietitians, specialists (infectious disease specialists, dermatologists, nephrologists, ophthalmologists, pediatrists, psychiatrists, and neurologists), and social workers.