HIV is the virus that causes AIDS. HIV weakens and slowly destroys the body’s immune system, leaving you vulnerable to life-threatening complications from an infection or certain cancers.

As HIV and AIDS battle your immune system, your central nervous system is also affected. HIV and AIDS both cause a number of neurological complications, particularly if HIV progresses to AIDS.

Today, antiretroviral medicines—when taken correctly and promptly—help to slow down the progression of HIV. They also help to delay the onset of or to decrease the risk of progression to AIDS. Controlling HIV can also reduce your risk for neurological complications of HIV.

Facts about HIV/AIDS

HIV is a virus that's sexually transmitted, but can also be passed from mother to baby and person to person by sharing a contaminated needle or through transfusion of contaminated blood. Untreated, the virus will continue to replicate in the body, becoming more and more advanced. Advanced HIV becomes AIDS. This often results in a number of neurological complications as the body becomes more damaged.

HIV doesn't seem to take over the cells in your nervous system, but it does cause significant inflammation in the body. This inflammation can damage the spinal cord and brain and prevent your nerve cells from working the way that they should.

Neurological complications may result not only from damage caused by the virus itself, but also from other side effects of HIV and AIDS, such as cancers that are associated with these diseases. Some of the drugs used to treat HIV and AIDS can also cause neurological complications while attempting to control the rapid spread of the virus. Certain genetic factors can influence the risk of neurological side effects from HIV medicines.

Neurological complications don't usually set in until HIV is advanced, typically when someone has AIDS. About half of adults with AIDS suffer from neurological complications related to HIV.

Types of neurological complications of HIV

HIV can cause many different conditions that affect the nervous system:

• Dementia. When HIV becomes very advanced, HIV-associated dementia or AIDS dementia complex can occur. These disorders impair cognitive function. This means that you may have trouble thinking, understanding, and remembering. This type of dementia can be life-threatening. It can often be prevented when antiretroviral medicines are taken correctly.

• Viral infections. HIV can increase your risk for several viral infections that strike the nervous system. Cytomegalovirus infections can negatively affect cognitive function, physical control (like the use of legs and arms and bladder control), vision and hearing, and your respiratory system, causing problems like pneumonia. People with AIDS are also likely to develop a herpes virus infection, like shingles, inflammation in the brain, and inflammation, in the spinal cord. Another condition, progressive multifocal leukoencephalopathy (PML) is also caused by a virus. PML is aggressive and dangerous. In some circumstances, it can be controlled with antiretroviral medicines.

• Fungal and parasitic infections. Cryptococcal meningitis is caused by a fungus and leads to serious inflammation of the spinal cord and brain. A parasite can cause an infection called toxoplasma encephalitis, which often leads to confusion, seizures, and extremely painful headaches. Both of these infections can be life-threatening.

• Neuropathy. HIV can cause damage to nerves throughout the body, resulting in significant pain or weakness, known as neuropathy. Neuropathy is most common in people with advanced HIV.

• Vacuolar myelopathy. This condition occurs when tiny holes develop in the fibers of the nerves of the spinal cord. It causes difficulty walking, particularly as the condition gets worse. It's common in people with AIDS who aren't receiving treatment and also in children with HIV.

• Psychological conditions. People with HIV or AIDS often develop anxiety disorders and suffer from depression. They may also experience hallucinations and significant changes in behavior.

• Lymphomas. Tumors called lymphomas often strike the brain of people with HIV. They're often related to another virus, similar to the herpes virus. Lymphomas can be life-threatening, but good management of HIV can make treating lymphomas more successful.

• Neurosyphilis. If an HIV-infected person also has syphilis that goes untreated, it can quickly progress and damage the nervous system. It can cause the nerve cells to break down and lead to loss of vision and hearing, dementia, and difficulty walking.

More on HIV-Related Neuropathy

HIV can affect peripheral sensory and motor nerves, thoracic nerves, cranial nerves or autonomic nerves. HIV neuropathy can manifest itself in multiple ways:

• It can affect multiple sensory and motor nerves in distal parts of the limbs and cause HIV polyneuropathy (also called distal symmetric polyneuropathy). Sometimes, polyneuropathy is due to a group of anti-HIV medications and is called antiretroviral toxic neuropathy. Symptoms include:

• Unusual sensations (paresthesia)

• Numbness and pain in their hands and feet. Often non-painful stimuli, such as touching, can elicit pain sensation.

• Weakness of the muscles in the feet and hands (at later stages of the illness)

• HIV can also affect one nerve at a time (HIV mononeuropathy) or cause an inflammatory neuropathy similar to Guillain-Barre syndrome (GBS). The symptoms depend on which nerve is affected. For example, it can affect thoracic nerves and cause numbness and pain in the chest wall, or it can affect cranial nerves and cause sensory or motor deficits in the face. In rare cases where HIV causes a GBS-like illness, the symptoms will be very similar to typical GBS.

Diagnosis of HIV neuropathies is based on medical history, clinical examination and supporting laboratory tests. These tests include electromyography with nerve conduction studies, skin biopsies to evaluate cutaneous nerve innervation, and nerve and muscle biopsies for histopathological evaluation. Treatment of HIV neuropathies depends on the type. Typical HIV polyneuropathy requires good control of HIV infection. Antiretroviral toxic neuropathy may require the cessation of the contributing drug. Nerve pain due to HIV polyneuropathy can be treated with anti-seizure medications, antidepressants or analgesics. 

Symptoms

Once HIV begins affecting your immune system, it can cause many different symptoms. HIV-related neurological complications may lead to:

• Suddenly forgetting things all the time or acting confused

• Feeling of weakness that keeps getting worse

• Changes in behavior

• Headaches

• Problems with balance and coordination

• Seizures

• Changes in your vision

• Difficulty swallowing

• Losing feeling in your legs or arms

• Mental health problems like anxiety and depression

Diagnosis

Although a blood test can diagnose HIV and AIDS, a number of other diagnostic tests are needed to look at the different parts of the nervous system and diagnose neurological problems. Tests often include:

• An electromyography to measure the electrical activity of the muscles and nerves

• Biopsy to analyze a sample of tissues and to help identify tumors in the brain or inflammation in the muscles

• Magnetic resonance imaging, which uses radio waves and powerful magnets to image the brain structures. This is the most powerful conventional imaging tool and can detect brain inflammation, many infections, tumors, strokes, and tissue destruction within the brain and spinal cord.

• Sample of cerebrospinal fluid to look for infections, bleeding, or other abnormalities affecting the spinal cord or brain

• CT scan, which uses X-rays to reconstruct a 3-D image of the brain. This test is faster and less expensive, but provides less detail than an MRI scan.

Treatment

Antiretroviral medicines are used to stop HIV from replicating and spreading throughout the body. They are also used to help reduce the risk that it will cause damage to the nervous system.

Specific neurological conditions and complications are treated differently. Cancer may be treated with chemotherapy and radiation, and bacterial infections need antibiotics. Certain medicines may help manage viral infections, and medicines to manage pain can help to ease nerve pain. Counseling and medicines, including antidepressants, may be used to manage some of the psychological conditions associated with HIV.

Prevention

Following all of your healthcare provider's recommendations, especially taking all antiretroviral medicines exactly as prescribed, can help control HIV and prevent its progression. Suppressing the virus with medicines can help prevent damage to the body, including nervous system damage and neurological complications.

Managing HIV

Living a healthy lifestyle can help you better control HIV and prevent the progression to AIDS. Eating a healthy diet and maintaining a healthy body weight, exercising regularly, practicing safe sex, and following your medicine regimen are all important steps in managing HIV.