Central Nervous System Basic Informations

The nervous system has two parts. The brain and spinal cord are the central nervous system (CNS). The nerves and muscles are the peripheral nervous system. Peripheral means around the outside.

People with CNS disease can have several nerve problems. A common problem is peripheral neuropathy. This causes nerve and muscle pain, especially in the feet, legs, and hands. See Fact Sheet 555 for more information. CNS problems include depression and problems with sleeping, balance, walking, thinking and memory.

At first, these were all called "AIDS Dementia Complex". However, there is a wide range of AIDS-related nerve troubles. AIDS Dementia means ongoing major problems with thinking, memory, and usually also with controlling the legs and arms.

Before combination antiviral therapy was available, about 20% of people with AIDS developed dementia. Strong antiviral medications have cut the rate of dementia by about 2/3. However, milder cases of dementia are increasing as people with CNS live longer.
Infection with hepatitis C and dependence on methamphetamines increase the risk of mental problems in people with CNS.


HOW ARE NEUROLOGIC PROBLEMS DIAGNOSED?
It can be difficult to know what's causing neurologic problems. They can be caused by vitamin deficiencies, opportunistic infections (see Fact Sheet 500), or by antiviral medications. Others are caused when CNS infects the brain or spinal cord.

Most mental problems don't show up until the late stages of CNS disease. If someone with a high T-cell count develops a neurologic problem, their doctor will look for other causes. These might include depression or the aging process. However, CNS infection can affect verbal memory, even in patients with no other symptoms of CNS disease. One study also found brain damage in people with CNS. This was true even when their viral load was controlled to undetectable levels.

Tell your doctor if you have any signs of neurologic problems. These include:

CNS problems can be caused by medications, swelling, or direct CNS infection of the brain and spinal cord.

If the problems are caused by medications, they usually go away if you stop taking the drugs.

A special concern is that people with CNS problems may need extra help remembering to take their medications.

Some newer medications are being studied for mental problems. The best results so far are with the drug selegeline.
Some researchers believe that neurologic problems can be reversed if they are treated in their early stages. However, other studies have found ongoing brain damage even in patients taking antiviral medications. Research in this area is continuing.