HIV is the virus that causes AIDS. Uncontrolled HIV can weaken and slowly break down your body's immune system. That makes you more likely to have serious or even deadly problems from HIV itself, other infections, or certain cancers.

As HIV and AIDS progressively affect your immune system, your central nervous system is also affected. HIV and AIDS both cause many nervous system (neurological) problems. That's especially true if someone's HIV infection is progressing toward AIDS. Or if the person currently has AIDS. AIDS is the most advanced stage of HIV.

Medicines can help people living with HIV prevent it from developing into AIDS. Controlling HIV can also lower your risk for nervous system problems caused by HIV.

HIV can directly infect many cells in the body, including those in your nervous system. But an even greater effect, particularly in the nervous system, is that it causes severe inflammation in your body. This inflammation can harm the spinal cord and brain. It can also stop your nerve cells from working the way that they should.

Nervous system problems may happen from damage caused by the virus itself. They can also happen from other effects of HIV and AIDS. These include infections and cancers caused by uncontrolled HIV. Some of the older medicines used to treat HIV and AIDS in the past could cause nervous system problems. This is rare with current medicines.

Nervous system problems don't usually start until HIV is advanced. Often this is when you have AIDS. About half of adults with AIDS have nervous system problems linked to HIV.

HIV can cause many health problems that affect the nervous system. Some of these health problems are listed below.

HIV-associated dementia or AIDS dementia complex can happen when HIV becomes very advanced. These disorders affect your ability to think (cognitive function). You may have trouble thinking, understanding, and remembering. This type of dementia can be life-threatening. It can often be prevented if you take medicines to treat the virus right way.

HIV can raise your risk for several viral infections that strike the nervous system. Cytomegalovirus infections can affect your ability to think. They can also affect how you control your leg movements and bladder. They can also affect eyesight, hearing, and breathing, and cause pneumonia. People with AIDS are also likely to get a herpes virus infection, such as shingles. They are also more likely to get inflammation in the brain and spinal cord. Progressive multifocal leukoencephalopathy (PML) is also caused by a virus. PML is aggressive and dangerous. In some cases, it can be controlled with the medicines used to treat HIV.

Cryptococcal meningitis is caused by a fungus. It causes serious inflammation of the spinal cord and brain. A parasite can cause an infection called toxoplasma encephalitis. It often causes confusion, seizures, and very painful headaches. Both of these infections can be deadly.

This is most common in people with advanced HIV. The virus causes damage to nerves throughout the body. This results in major pain or weakness. Some of the early HIV medicines caused neuropathy as a side effect.

This health problem occurs when tiny holes develop in the fibers of the nerves of the spinal cord. It causes trouble walking, particularly as it gets worse. It's common in people with AIDS who aren't getting treatment. It's also common in children with uncontrolled HIV.

People with HIV or AIDS often develop anxiety disorders and depression. They may also have hallucinations and major changes in behavior, but this is usually only after progression to AIDS.

People with HIV can develop tumors called lymphomas that grow in or spread to the brain. Lymphomas can be deadly. But controlling your HIV infection can make treating lymphomas more successful.

If a person with HIV also has untreated syphilis, the syphilis can get worse and harm the nervous system. It can cause the nerve cells to break down. It can lead to eyesight and hearing loss, dementia, and walking problems.

• Forgetfulness or confusion
• Weakness of the arms, legs or whole body
• Changes in behavior
• Headaches
• Problems with balance and coordination
• Seizures
• Changes in your eyesight
• Trouble swallowing
• Wide swings in your heart rate or blood pressure
• Diarrhea or loss of bladder control
• A loss of feeling in your legs or arms
• Mental health problems, such as anxiety and depression

A blood test can diagnose HIV and AIDS. But you will need other tests to look at the different parts of the nervous system and diagnose problems. Tests often include:

• CT scan. This test uses X-rays and a computer to make a 3-D picture of the brain. This test gives less detail than an MRI.
• MRI. This test uses radio waves and strong magnets to take pictures of the brain structures without the use of X-rays. It can find brain inflammation, infections, tumors, strokes, and damaged tissue within the brain and spinal cord.
• Spinal tap (lumbar puncture). This procedure withdraws a sample of cerebrospinal fluid to look for infections, bleeding, or other problems affecting the spinal cord or brain.
• Electromyography and nerve conduction study. This measures the electrical activity of the muscles and nerves.
• Biopsy. This examines small tissue samples to diagnose tumors in the brain or inflammation in the muscles.

There is currently no single treatment to cure neurological complications from HIV/AIDS. Medicines may be used to help stop HIV from damaging the body. They are also used to help lower the risk that HIV will damage the nervous system.

Each nervous system problem is treated differently. Cancer may be treated with chemotherapy and radiation. Bacterial infections are treated with antibiotics. Certain medicines may help with viral infections or nerve pain. Counseling and antidepressant medicine may be used to treat some of the mental health problems linked to HIV.

Get tested if you are at risk for HIV. If positive, get treatment for HIV before it does a lot of damage. Start HIV medicines right away and take them correctly. Go back to your doctor regularly to have your blood kept track of to see that your HIV is under control. Try to prevent picking up new STIs (sexually transmitted infections). Get tested for STIs regularly. A healthy lifestyle that includes a well-balanced diet and physical exercise can help you maintain your best possible health.

• HIV and AIDS can affect your nervous system and cause problems, such as dementia, viral infections of the brain, and nerve problems.
• You might need certain tests to help diagnose the problems.
• HIV medicines may help stop the spread of the virus in your body and prevent or reverse the damage. They may also lower the risk for nervous system damage.
• Living a healthy lifestyle and taking medicines as prescribed may help you better control HIV and prevent it from progressing to AIDS.

Tips to help you get the most from a visit to your doctor:

• Know the reason for your visit and what you want to happen.
• Before your visit, write down questions you want answered.
• Bring someone with you to help you ask questions and remember what your doctor tells you.
• At the visit, write down the name of a new diagnosis and any new medicines, treatments, or tests. Also write down any new instructions your doctor gives you.
• Know why a new medicine or treatment is prescribed and how it will help you. Also know what the side effects are and when they should be reported.
• Ask if your condition can be treated in other ways.
• Know why a test or procedure is recommended and what the results could mean.
• Know what to expect if you do not take the medicine or have the test or procedure.
• If you have a follow-up appointment, write down the date, time, and purpose for that visit.
• Know how you can contact your doctor if you have questions.