What is AIDS?
AIDS (acquired immune deficiency syndrome) is a condition that occurs in the most advanced stages of human immunodeficiency virus (HIV) infection. It may take many years for AIDS to develop following the initial HIV infection.
Although AIDS is primarily an immune system disorder, it also affects the nervous system and can lead to a wide range of severe neurological disorders.
How does AIDS affect the nervous system?
The virus does not appear to directly invade nerve cells but it jeopardizes their health and function. The resulting inflammation may damage the brain and spinal cord and cause symptoms such as confusion and forgetfulness, behavioural changes, headaches, progressive weakness, and loss of sensation in the arms and legs.
Cognitive motor impairment or damage to the peripheral nerves is also common. Research has shown that the HIV infection can significantly alter after the size of certain brain structures involved in learning and information processing.
Other nervous system complications that occur as a result of the disease or the drugs used to treat it include pain, seizures, shingles, spinal cord problems, lack of coordination, difficult or painful swallowing, anxiety disorder, depression, fever, vision loss, gait disorders, destruction of brain tissue, and coma. These symptoms may be mild in the early stages of AIDS but can become progressively severe.
What are some of the neurological complications that are associated with AIDS?
AIDS-related disorders of the nervous system may be caused directly by the HIV virus, by certain cancers and opportunistic infections (illnesses caused by bacteria, fungi, and other viruses that would not be otherwise affect people with healthy immune systems), or by toxic effects of the drugs used to treat symptoms. Other neuro-AIDS disorders of unknown origin may be influenced by but are not caused directly by the virus.
AIDS dementia complex (ADC), or HIV-associated dementia (HAD), occurs primarily in persons with more advanced HIV infection. It is rare when anti-retroviral therapy is used.
- Central nervous system (CNS) lymphomas
- Cryptococcal meningitis
- Crypmegalovirus (CMV) infections
- Herpes virus infections
People with AIDS may suffer from several different forms of neuropathy, or nerve pain, each strongly associated with a specific stage of active immunodeficiency disease. Peripheral neuropathy described damage to the peripheral nerves, the vast communications network that transmits information between the brain and spinal cord to every other part of the body.
Peripheral nerves also send sensory information back to the brain and spinal cord. HIV damages the nerve fibers that help conduct signals and can cause several different forms of neuropathy. Distal sensory polyneuropathy causes either a numbing feeling or a mild to painful burning or tingling sensation that normally begins in the legs and feet.
These sensations may be particularly strong at night and may spread to the hands. Affected persons have a heightened sensitivity to pain, touch, or other stimuli. Onset usually occurs in the later stages of the HIV infection and may affect the majority of advanced-stage HIV patients.
- Neurosyphilis
- Progressive multifocal leukoencephalopathy (PML)
- Psychological and neuropsychiatric disorders can occur
- Toxoplasma encephalitis, also called cerebral toxoplasmosis
- Vacuolar myelopathy
How are these disorders diagnosed?
Based on the results of the individual’s medical history and a general physical exam, the physician will conduct a thorough neurological exam to assess various functions: motor and sensory skills, nerve function, hearing and speech, vision, coordination and balance, mental status, and changes in mood or behaviour.
The physician may order laboratory tests and one or more of the following procedures to help diagnosis neurological complications of AIDS.
Brain imaging can reveal signs of brain inflammation, tumours and CNS lymphomas, nerve damage, internal bleeding or haemorrhage, white matter irregularities, and other brain abnormalities. Several painless imaging procedures are used to help diagnosis neurological complications of AIDS.
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- Computed tomography (also called a CT scan)
- Magnetic resonance imaging (MRI)
- Electromyography, or EMG
- Biopsy
- Cerebral fluid analysis
How are these disorders treated?
No single treatment can cure the neurological complications of AIDS. Some disorders require aggressive therapy while others are treated symptomatically.
Neuropathic pain is often difficult to control. Medicines range from analgesics sold over the counter to antiepileptic drugs, opiates, and some classes of antidepressants. Inflamed tissue can press on nerves, causing pain. Inflammatory and autoimmune conditions leading to neuropathy may be treated with corticosteroids, and procedures such as plasmapheresis (or plasma exchange) can clear the blood of harmful substances that cause inflammation.
Treatment options for AIDS- and HIV-related neuropsychiatric of psychotic disorders include antidepressants and anticonvulsants. Psychostimulants may also improve depressive symptoms and combat lethargy. Antidementia drugs may relieve confusion and slow mental decline, and benzodiazepines may be prescribed to treat anxiety. Psychotherapy may also help some individuals.
Aggressive antiretroviral therapy is used to treat AIDS dementia complex, vacuolar myopathy, progressive multifocal leukoencephalopathy, and cytomegalovirus encephalitis. HAART, or highly active antiretroviral therapy, combines at least three drugs to reduce the amount of virus circulating in the blood and may also delay the start of some infections.
Other neuro-AIDS treatment options include physical therapy and rehabilitation, radiation therapy and/or chemotherapy to kill or shrink cancerous brain tumours that may cause by the HIV virus, antifungal or antimalarial drugs to combat certain infections associated with the disorder, and penicillin to treat neurosyphilis.
