Neurological aspects of HIV infection (neuroAIDS) || Neurological manifestations of HIV infection

Main diseases of the nervous system in HIV

Before listing the pathologies of this system that accompany this terrible infection, it should be noted that they are often diagnosed much earlier than the virus itself. Damage to the nervous system due to HIV can be expressed by the following manifestations:

• Deviations from the norm in the condition of cerebral vessels. This pathology is directly related to the effect of the immunodeficiency virus on the central nervous system. It is characterized by severe headaches, nausea, and dizziness.
• AIDS is dementia, which in ordinary life is more common in people after sixty. But in the case of immunodeficiency syndrome, this disease becomes significantly younger.
• Damage to the central nervous system due to HIV infection, which is a consequence of diseases such as tuberculosis or syphilis. The latter are often observed in infected people. In this case, there may be problems not only with nerves, but also with joints.
• Aseptic meningitis is a disease that can occur at different stages of the virus. It poses a great danger, but complications of this type of illness are much less. Meningic pathologies of other types (purulent, viral, etc.) progress faster.

If patients had concomitant diseases before infection with the virus and the onset of its progression, their course, as a rule, worsens.

The peculiarities of damage to the central nervous system in HIV are such that the clinical picture of some pathologies and ailments changes significantly. That is why it can be problematic to diagnose certain deviations from the norm in this area in infected patients.

Development of the disease

The disease does not appear immediately. It can take ten years from the moment of infection with the virus to the development of immunodeficiency. The following stages of disease development are distinguished:

• incubation period;
• infectious period;
• latent period;
• development of secondary diseases;
• AIDS.

The incubation period is the period of time between a person becoming infected and the ability to determine the presence of the virus in the blood using laboratory methods. As a rule, this period lasts up to two months. During the incubation period, the presence of the virus in the patient’s blood cannot be detected by analysis.

After the incubation period, the infectious period begins. During this period of time, the body actively tries to fight the virus, so symptoms of infection appear. Typically, patients report fever, flu-like symptoms, and respiratory and gastrointestinal infections. The period lasts up to two months, but symptoms are not present in every case.

During the latent period of disease development, there are no symptoms. During this period of time, the virus infects the patient’s cells, but does not manifest itself in any way. This period can last a long time, up to 15-20 years.

The latent period of the virus in the body is replaced by the stage of the addition of secondary diseases. This is due to the reduction of lymphocytes responsible for the body’s immune defense, as a result of which the patient’s body is not able to resist various pathogens.

The last period of disease development is AIDS. At this stage, the number of cells that allow the body to provide complete immune protection reaches a critically low value. The immune system completely loses the ability to resist infections, viruses and bacteria, resulting in damage to internal organs and the nervous system.

Etiology

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The AIDS virus was described in 1983 simultaneously in France (at the L. Pasteur Institute) and in the USA (in the laboratory of R. Gallo). This virus from the group of retroviruses has very high variability. Currently, several main types of HIV have been described. The virus contains RNA as its genetic material, which is easily integrated into the genomic material of a human cell using a special viral enzyme - viral transcriptase. HIV actively multiplies in the cell; some infected cells, under the influence of the virus, merge, becoming giant and multinucleated. HIV can circulate in a person’s blood and cells for a long time without exerting a pathogenic effect. Not all HIV carriers develop AIDS, although they are all at risk. The mechanisms for maintaining this latent period, as well as the reasons for the activation of the virus, are not yet entirely clear. It is assumed that additional external factors are of decisive importance, including other infections that cause disruption of the compensatory mechanisms of latent virus carriage. The state of the immune system as a whole is of great importance, which is associated both with previous toxic and infectious effects on a given organism, and with the genetic characteristics of the functioning of the immune system of a given person.

HIV is unstable in the external environment. So far, four main methods of infection have been proven.

The first is through sexual intercourse. This route of infection, especially during homosexual contacts, prevailed in the early stages of the pandemic and is largely associated with microtraumas of the mucous membranes. Infection through heterosexual contact is becoming increasingly important.

Currently, the main (second) route of infection is the reuse of medical instruments contaminated with infected blood, which most often occurs when drug addicts repeatedly use needles and syringes. It is possible for medical personnel to become infected through accidental injections with contaminated medical instruments. Cases of transmission of the virus during accidental cuts in a hairdressing salon and poor control over the processing of instruments in dental offices have been described.

The third route of transmission - through blood products and its components - was important exclusively in the early stages of the development of the pandemic. At the end of the 80s, mandatory monitoring of all blood products to detect viral material was established throughout the world, so this route of transmission has practically lost its significance.

The fourth route —transmission of HIV from an infected mother to a child, most likely transplacentally—does not have much epidemiological significance. The presence of other ways of transmitting HIV from one person to another has not yet been proven. The incubation period for this infectious disease is difficult to determine.

HIV is tropic to cells of the immune and nervous systems. The virus specifically infects cells that have a CD4 receptor molecule on their membrane. Among the cells of the immune system, this receptor is mainly found in T-lymphocytes, which perform the functions of helper cells. To a lesser extent, this protein is present on the membranes of other cells, in particular cells of the nervous system, especially microglia, cells of the vascular wall, etc. HIV binds to the CD4 receptor of the cell with the participation of its surface protein, which can subsequently be expressed on the surface of the infected cell.

Classification

HIV-1-associated asymptomatic neurocognitive disorder (AND)

Neuropsychological testing reveals impairment (at least one standard deviation) of cognitive function in ≥2 functional domains. This cognitive impairment does not interfere with daily life.

HIV-1-associated mild neurocognitive disorder (MND)

Results of testing of cognitive function as in MND. At least minor impact on daily activities (at least one of the following):

a) The patient complains of loss of ability to think quickly, decreased performance (in the workplace and at home), and decreased social activity.

b) According to the observations of people who know the patient well, the patient has become slower in thinking, as a result of which he has become less effective in coping with professional tasks and household chores or has become less socially active.

HIV-1-associated dementia (HAD)

Marked acquired impairment of cognitive function. The results of testing of cognitive function are the same as for MND, but in most cases, impairments are detected in several functional areas and are at least two standard deviations. These disorders significantly affect daily life (professional duties, household chores, social activities).

VANR may be a manifestation of IRIS.

How does AIDS affect the nervous system?

The virus probably does not directly penetrate nerve cells, but it threatens their normal condition and functioning. The resulting inflammation can damage the brain and spinal cord and lead to symptoms such as confusion and forgetfulness, behavior changes, headaches, progressive weakness and loss of feeling in the arms and legs. Cognitive motor impairment or peripheral nerve damage is also common. Scientific research has shown that HIV infection can significantly change the size of certain brain structures that are responsible for learning and information processing.

Other nervous system complications that occur as a result of the disease include pain, cramps, shingles, shingles, spinal cord problems, lack of coordination, difficulty swallowing, anxiety disorder, depression, fever, loss of vision, difficulty walking, destruction of brain tissue and coma. These symptoms may be mild in the early stages of AIDS, but can progress and become severe.

Neurological complications occur in more than 50 percent of adults with AIDS. Nervous system complications in children may include developmental delays, loss of previously learned skills, brain damage, pain, reduced skull size, slow growth, vision problems and bacterial infections.

Diagnostics

Based on the results of the medical history and general physical examination, the doctor will perform a thorough neurological examination to determine the performance of various body functions: motor and sensory skills, nervous system function, hearing and speech, vision, coordination and balance, mental status, and changes in mood or behavior. Your doctor may order laboratory tests and one or more of the following procedures to help diagnose neurological complications of AIDS.

Brain imaging can look for signs of brain inflammation, central nervous system tumors and lymphoma, nerve damage, internal bleeding or hemorrhage, white matter abnormalities, and other brain abnormalities. There are several painless imaging procedures used to diagnose neurological complications of AIDS.

Computed tomography (also called CT scan). This procedure uses X-rays and a computer to create two-dimensional images of bone and tissue, including inflammation, some brain tumors and cysts, brain damage from head trauma and other disorders. CT scans provide more detail than X-rays alone.

Magnetic resonance imaging (MRI). This study uses a computer, radio waves and a powerful magnetic field to obtain a detailed three-dimensional picture, or two-dimensional “slice,” of body structures, including tissues, organs, bones and nerves. MRI does not use ionizing radiation (like X-rays) and allows doctors to get the best picture of tissue near the bone.

Functional MRI (fMRI) also uses the magnetic properties of blood to pinpoint active areas of the brain and record how long they remain active. The procedure evaluates brain damage from head trauma or degenerative disorders such as Alzheimer's disease, and can detect and monitor other neurological disorders, including AIDS dementia complex.

Magnetic resonance spectroscopy (MRS) involves using a strong magnetic field to study the biochemical composition and concentration of hydrogen-based molecules, some of which are very specific to nerve cells in different areas of the brain. MRS is used experimentally to detect brain lesions in people with AIDS.

Electromyography, or EMG, is used to diagnose nerve and muscle dysfunction (such as neuropathy and nerve damage caused by the HIV virus) and spinal cord disease. It records spontaneous muscle activity and muscle activity caused by peripheral nerves.

A biopsy is a research method in which tissue is removed and studied from the body. To determine intracranial disorders and tumor type, a brain biopsy is used, which involves surgically removing a small piece of the brain or tumor. Unlike most other types of biopsies, this requires hospitalization. A muscle or nerve biopsy can help diagnose neuromuscular problems, while a brain biopsy can help diagnose swelling, inflammation or other irregularities.

CSF (cerebrospinal fluid) analysis can detect bleeding or hemorrhage in the brain, infections of the brain or spinal cord (such as neurosyphilis), and any harmful buildup of fluid. It can also be used to screen for viruses that can affect the brain. A sample of the fluid is removed with a needle under local anesthesia and examined to identify any irregularities.

Development of HIV encephalopathy

Dementia develops due to damage to brain tissue cells by a virus. In patients, neuroglial cells (astrocytes) are affected, microglial cells, which are actively involved in the fight against infection and inflammation, are damaged. Other causes include accelerated neuronal death (apoptosis). In patients, the electrolyte balance in the brain tissue is disturbed.

Pathological processes are cyclical and depend on the state of the patient’s immune system. Perhaps this circumstance explains the earlier development of dementia in some patients.

Subsequently, other inflammatory processes join in the destruction of neurons. Brain tissue begins to actively attack microbes, viruses, fungal infections, and protozoa. In patients, as a result of intoxication, microcirculation in the brain tissue is disrupted, which leads to increased intracranial pressure, cerebral edema, and a decrease in oxygen content in the blood.

Diagnostic features

Diagnosis of HIV encephalopathy involves collecting anamnesis and mandatory examinations such as MRI, CT scan of the brain, and EEG. Clinical blood diagnostics and additional types of examination are prescribed depending on the patient’s health status and a history of concomitant diseases.

Encephalitis is a group of inflammatory diseases of the brain substance that are infectious, allergic or toxic in nature. If a patient is diagnosed with a disease, he should be hospitalized immediately. In case of encephalitis, a person is placed in an infectious diseases or specialized neurological department and is prescribed strict bed rest and constant monitoring.

Therapy and prognosis

Timely treatment of the underlying disease will help to avoid the development of neurological disorders in HIV. Typically, dementia caused by encephalopathy develops only if the patient is not treated therapeutically.

Any damage to the nervous system caused by HIV is treated with potent antiviral drugs (for example, zidovudine).

To date, the best results in the treatment of nervous system diseases associated with HIV are shown by HAART therapy. This therapy is based on the simultaneous use of two groups of antiretroviral drugs.

Timely treatment can stop further development of encephalopathy and dementia. In some cases, it is possible to stop the progression of dementia, and in others, it is possible to delay the development of cognitive impairment for a long time.

HIV encephalitis also involves taking antidepressants to correct the patient's mental state. At the initial stages of development of the disorder, patients experience depressive states and sleep disorders, which should be combated with the help of special medications.

It is impossible to say unequivocally what the prognosis for patients with HIV encephalopathy is. This depends on the characteristics of the damage to the nervous system and brain in a particular patient.

HIV symptoms and diagnosis

Due to the long incubation period, symptomatic detection of the virus is impractical. Infection can only be diagnosed using a laboratory method - this is the only way to reliably determine a patient’s HIV status.

Since the virus attacks the patient's immune system, the symptoms and prognosis of the disease are quite vague and characteristic of various diseases. The initial signs are similar to those of ARVI or influenza:

• difficulty breathing;
• pneumonia;
• sudden weight loss;
• migraine;
• blurred vision;
• inflammatory diseases of the mucous membranes;
• nervous disorders, depressive states.

When the virus is transmitted from an infected mother to an infant, the disease develops very rapidly. Symptoms increase rapidly, which can lead to death in the first years of a child’s life.

Neurological complications of AIDS

AIDS-related nervous system disorders may be caused by the HIV virus itself, certain cancers, and opportunistic infections (diseases caused by bacteria, fungi, and other viruses that would not otherwise affect people with healthy immune systems) or the toxic effects of drugs used to treat symptoms. Other neuroAIDS diseases of unknown origin may be affected by them but are not directly caused by the virus.

AIDS dementia or HIV-associated dementia develops primarily in patients with more severe forms of HIV infection. Symptoms include encephalitis (inflammation of the brain), behavioral changes, and a gradual decline in cognitive function, including problems with concentration, memory, and attention. People with HIV-associated dementia also experience progressive slowing of motor function and loss of dexterity and coordination. If left untreated, AIDS dementia can lead to death. In some cases, antiretroviral therapy is used in treatment. More mild cognitive impairment is called HIV-associated neurocognitive disorder. Neuropsychological testing can detect disorders that are not obvious, even in the absence of symptoms.

Central nervous system lymphomas are cancers that either initially develop in the brain or are the result of cancer that has spread from elsewhere in the body. CNS lymphomas are almost always associated with Epstein-Barr virus (a common human virus in the herpes family). Symptoms include headache, seizures, vision problems, dizziness, speech problems, paralysis and mental disturbances. Patients may develop one or more CNS lymphomas. Due to progressive and worsening immunodeficiency, the prognosis of the disease is poor, but with HIV therapy the prognosis is better.

Cryptococcal meningitis occurs in about 10 percent of untreated AIDS patients and in other people whose immune systems are severely suppressed by disease or medications. The disease is associated with the fungus Cryptococcus neoformans, which is commonly found in dirt and bird droppings. The fungus first invades the lungs and spreads to the covering of the brain and spinal cord, causing inflammation. Symptoms include fatigue, fever, headache, nausea, memory loss, confusion, drowsiness and vomiting. If the disease is not treated, people with cryptococcal meningitis may fall into a coma and die.

Cytomegalovirus infection (CMVI) can occur simultaneously with other infections. Symptoms of CMV infection include weakness of the arms and legs, problems with hearing and balance, altered mental states, dementia, peripheral neuropathy, coma, and retinal diseases that can lead to blindness. Cytomegalovirus infection of the spinal cord and nerves can lead to lower limb weakness and paralysis, severe low back pain, and bladder dysfunction. The disease can also lead to pneumonia and gastrointestinal problems.

Herpes viral infections are often seen in people with AIDS. The herpes zoster virus, which causes chickenpox and shingles, can infect the brain and cause encephalitis and myelitis (inflammation of the spinal cord). Ringworm appears as a rash of blisters and severe pain in the area of ​​the skin caused by an infected nerve. In people exposed to herpes zoster, the virus may remain inactive in nerve tissue for many years until it is reactivated as shingles. This reactivation is common in AIDS patients due to their weakened immune system. Signs of shingles include painful blisters (such as those seen with chickenpox), itching, tingling, and nerve pain.

People with AIDS may suffer from several different forms of neuropathy, or nerve pain, each of which is strongly associated with a particular stage of active immunodeficiency. Peripheral neuropathy describes damage to the peripheral nerves, the vast network of transmitters that carries signals 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 nerve fibers that help transmit signals and can cause several different forms of neuropathy. Distal sensory polyneuropathy causes either an overwhelming feeling or a mild or painful burning or tingling sensation that usually begins in the legs and feet. These sensations may be especially severe at night and may spread to the arms. Patients have increased sensitivity to pain, touch, or other irritants. Onset typically occurs in the later stages of HIV infection and can affect most patients with advanced HIV infection.

Neurosyphilis , the result of untreated syphilis infection, is common and rapidly progressive in patients with HIV infection. It can cause slow degeneration of nerve cells and nerve fibers that carry sensory information to the brain. Symptoms, which may not be present for decades after the initial infection and vary from person to person, include weakness, decreased reflexes, unsteady gait, progressive joint degeneration, loss of coordination, episodes of severe pain and sensory disturbances, as well as dementia, deafness, blurred vision and impaired reaction to light. The disease is more common in men than in women. Its onset is widespread in middle age.

Progressive multifocal leukoencephalopathy (PML) primarily affects people with suppressed immune systems (including about 5 percent of people with AIDS). PML is caused by the virus Human polyomavirus 2 (JC virus), which infects several parts of the brain and destroys the cells that produce myelin, the protective covering of nerve and brain cells. Symptoms include various types of mental impairment, vision loss, speech impairment, ataxia (inability to coordinate movements), paralysis, brain lesions, and eventually coma. Progressive multifocal leukoencephalopathy progresses steadily, and death usually occurs within 6 months of the onset of initial symptoms. However, at the current stage of treatment, restoration of immunity using highly active antiretroviral therapy allows survival in more than half of cases of PML caused by HIV.

Damage to the central nervous system in HIV infection

HIV infection is a viral disease characterized by slowly progressive destruction of the immune system with the development of acquired immunodeficiency syndrome (AIDS). The causative agent is the human immunodeficiency virus (HIV, human immunodeficiency virus).

The disease goes through four stages in succession:

Stage I - incubation stage, lasts for 2-6 weeks or more;

Stage II - the stage of primary manifestations, includes mononucleosis-like syndrome, an asymptomatic phase and a phase of generalized lymphadenopathy, some patients develop headache, myalgia, arthralgia;

Stage III - the stage of secondary diseases, characterized by recurrent lesions of the skin, mucous membranes and internal organs of a fungal, bacterial or viral nature, recurrent herpes zoster, pulmonary tuberculosis, repeated pharyngitis, sinusitis, Kaposi's sarcoma, esophageal candidiasis, lesions of the nervous system of various etiologies, loss occurs body weight more than 10%;

Stage IV - terminal.

Signs of damage to the nervous system can be observed at any stage of HIV infection: in the subclinical phase - in 20% of patients, in the stage of a full clinical picture of the disease - in 40-50%, in later stages - in 30-90%.

Early neurological disorders manifest themselves 8-12 weeks after infection in the presence of HIV antibodies. At a later date, secondary neuroAIDS appears as a result of developed immunodeficiency and activation of opportunistic infections. Its clinical forms also differ in significant diversity.

Of significant importance is the fact that various causes may underlie lesions of the central nervous system:

1) direct damage to brain tissue by the human immunodeficiency virus;

2) association of brain damage with cytokines produced by infected perivascular macrophages;

3) exposure to pathogens of a number of secondary infections;

4) neoplasms, primarily isolated B-cell lymphomas.

According to numerous studies, the following routes of HIV penetration into the central nervous system are currently being considered.

I. The virus can be transported to the central nervous system as part of blood cells - lymphocytes and macrophages. In a monocyte, virus replication is limited; however, upon penetration into tissue, where the monocyte matures into a macrophage, its replication increases. Newly formed viral particles cause cell changes and tissue damage. HIV-infected monocytes play the role of a “Trojan horse”, transporting the virus into the central nervous system and ensuring its contact with neurons and neuroglia.

II. HIV can enter the central nervous system through nerve fibers. Glial cells become infected due to their membrane lysis by the gp120 protein. The entry of dissolved gp120 into the cerebrospinal fluid may also trigger an autoimmune process against CNS cells.

III. HIV can enter the central nervous system through the gaps between the endothelial cells of the capillaries and thus infect neuroglial cells.

NeuroAIDS is the general name for clinical manifestations of damage to the nervous system that develops in patients with HIV infection. In many patients, HIV infection from the very beginning occurs as a neuroinfection, i.e. neurological disorders dominate and are the direct cause of death, while other manifestations of the disease are minimal. In more than 30% of cases, neurological manifestations are the first symptoms of the transition from latent HIV virus carriage to the AIDS clinic.

There are two main groups of damage to the nervous system during HIV infection: direct damage and opportunistic processes.

The first group is a consequence of direct damage to the nervous system by a retrovirus. Symptom complexes associated with the direct influence of the virus - HIV-associated cognitive-motor complex (HIV-associated minimal cognitive-motor impairment, HIV-associated dementia and HIV-associated myelopathy), other CNS lesions associated with HIV infection (aseptic meningitis, progressive encephalopathy), as well as HIV-associated lesions (polyneuropathies and myopathies). They arise due to the direct damaging effect of the virus, the neurotoxic effect of its components and other substances (free radicals, cytokines, enzymes, etc.) produced locally in the tissue in response to the virus entering cells, including infected cells, as well as due to autoimmune reactions .

HIV-associated cognitive-motor complex.

This complex includes three symptom complexes - HIV-associated dementia, HIV-associated myelopathy and HIV-associated minimal cognitive-motor disorders.

HIV-associated dementia (HIV encephalopathy). Occurs in more than 60% of AIDS patients, in 25% even before the development of a clear clinical picture of AIDS.

Clinical manifestations:

1. Cognitive impairments dominate, progressing to the level of subcortical type dementia (sometimes defined as subcortical-frontal type): slowing of psychomotor processes, inattention, memory loss, impaired information analysis processes

2. Emotional and behavioral disorders, often with depression, dysphoria, apathy.

3. In rare cases, the disease may manifest itself as affective disorders (excitement, psychosis) or seizures.

4. In the initial stages, dementia is detected only through neuropsychological testing. Subsequently, dementia can rapidly progress to disorientation and confusion, and in the final stage akinetic mutism may develop.

CSF: in more than 1/3 of patients, pleocytosis of no more than 50 cells in 1 μl, a slight increase in protein content, and an increase in the level of class G immunoglobulins can be detected.

EEG: slow waves in the ?- and ?-range are often recorded, paroxysmal activity is rarely recorded.

MRI: generalized atrophy with widening of the ventricles and cortical sulci, multifocal symmetrical focal changes in the white matter, hyperintense on T2-weighted images, without mass effect and without accumulating paramagnetic contrast agent, with predominant involvement of the frontal and parietal lobes. In some cases of neuroAIDS, the MRI pattern is very similar to multiple sclerosis (MS), which leads to incorrect conclusions by radiologists.

Magnetic resonance spectroscopy (MRS) reveals a decrease in the N-acetylaspartate peak (a neuronal marker) in the early stages of the disease, when tomograms are still normal.

HIV-associated myelopathy.

Occurs in 20% of AIDS patients and is characterized by damage to the spinal cord. The pathological process is most often localized at the level of the thoracic segments and is characterized by the formation of cavities (vacuoles), probably associated with myelin swelling.

Noted:

1. Increasing weakness in the extremities (paresis), mainly in the lower ones, but the upper ones can also be affected

2. There is a significant decrease in strength, an increase in muscle tone of the spastic type

3. The presence of sensitive ataxia and disturbance of pelvic functions of the true type, up to urinary and fecal incontinence

4. Frequent combination with HIV encephalopathy

5. Sensitivity disorders of the conductive type are possible, more often of the hemitype

CSF: nonspecific changes in the form of pleocytosis, increased total protein content.

MRI: spinal cord atrophy and areas of signal enhancement on T2-weighted images, less commonly areas of swelling, and cavities are visualized.

HIV-associated minimal cognitive-motor disorders occur in more than 80% of patients. They mean the least pronounced disorders, which are usually detected in people with an already established diagnosis during neuropsychological testing in specialized clinics. Changes in neuropsychological tests are similar to those in dementia, but to a much lesser extent, forgetfulness, slowing of thought processes, and decreased ability to concentrate are characteristic. Typically a personality change with limited motivation. Neurological disorders are also possible in the form of ataxia when walking, dysmetria in coordination tests. Changes when using additional methods of examining the nervous system, as a rule, are not detected.

Acute aseptic meningitis and meningoencephalitis.

Occurs on average in 20% of patients during the acute stage of infection. The most likely mechanism for the development of this acute inflammation of the meninges is associated with humoral autoimmune reactions during the primary response to virus antigens, even before the development of immunodeficiency.

Clinically:

1. Moderately expressed cerebral and meningeal syndromes: severe headache, drowsiness and manifestations of meningism predominate, rarely with damage to the cranial nerves and transient encephalopathy.

2. This can be combined with an increase in body temperature and asthenic manifestations, which is also characteristic of serous meningitis.

3. In rare cases, meningoencephalitis develops, starting with epileptic seizures and disturbances of consciousness up to coma. In this case, lymphadenopathy, maculopapular rash, splenomegaly can be detected, which is characteristic of an immediate humoral autoimmune reaction. The development of meningoencephalitis is associated with generalized vasculitis, as well as an acute reaction to the ingestion of a foreign protein.

4. Clinical manifestations usually regress on their own within 1-4 weeks.

The diagnosis is established only after additional research, in particular lumbar puncture.

CSF: Combination of the above symptoms with mononuclear pleocytosis exceeding 5 cells per 1 mm3, increased level of immunoglobulins. Changes on tomography are minimal and nonspecific.

HIV-associated symptoms of peripheral nervous system damage.

Occurs in more than 50% of patients at any stage of the disease, the causes are both primary damage by the virus and autoimmune mechanisms. The most characteristic are distal polyneuropathies with a predominance of sensory disorders (distal sensory polyneuropathy), usually in the form of numbness, burning, paresthesia and dysesthesia, often in the area of ​​​​the feet and palms, sometimes with mild weakness and decreased tendon reflexes. It is possible to develop more severe inflammatory polyneuropathies in the form of subacute multifocal multiple polyneuropathy or multiple neuritis with predominant damage to the lower extremities. Acute motor polyneuropathies (like Guillain-Barré syndrome) with increasing paresis rarely develop, which requires emergency assistance in the form of plasmapheresis. It should be taken into account that polyneuropathies can also be observed with secondary lesions and opportunistic infections, and have an iatrogenic nature: for example, polyneuropathies can occur with CMV or after the use of antiviral drugs and chemotherapeutic agents.

The second group of diseases is associated with damage to the nervous system by opportunistic infections and neoplastic processes in HIV infection. These diseases are detected in more than 50% of patients, in the later stages of AIDS - in almost all. They develop against the background of progressive immunodeficiency in the advanced stages of AIDS.

Opportunistic infections are associated with pathogens that cause disease in humans only against the background of immunodeficiency. The most common are PML, cerebral toxoplasmosis, cryptococcal meningitis, encephalitis and polyradiculoneuritis caused by cytomegalovirus and herpes group viruses, tuberculosis with brain damage, and among neoplastic diseases - primary CNS lymphoma. There is often a combined infection with several pathogens, the presence of both opportunistic infections and a neoplastic process, for example, lymphoma or Kaposi's sarcoma localized in the vessels of the brain. An MRI scan of the brain is very informative for diagnosis.

Sources:

1. Boyko A.N., Mazus A.I., Tsyganova E.V., Ovcharov V.V., Boyko O.V., Serkov S.V., Gusev E.I. // Neurological manifestations of HIV infection. JOURNAL OF NEUROLOGY AND PSYCHIATRY, 9, 2012; Vol. 2

2. Belyakov N.A., Medvedev S.V., Trofimova T.N., Rassokhin V.V., Dementyeva N.E., Shelomov S.A. // Mechanisms of brain damage in HIV infection. Bulletin of the Russian Academy of Medical Sciences. 2012; 9:4–12.

NeuroAIDS symptoms

Primary neuroAIDS often has an asymptomatic subclinical course. In 10-20% of cases, neurological symptoms debut in the first 2-6 weeks of HIV infection (seroconversion period). During this period, against the background of febrility, lymphadenopathy and skin rashes, some patients show signs of aseptic meningitis and acute radiculoneuropathy. Other clinical forms of primary neuroAIDS (HIV encephalopathy, HIV myelopathy) occur predominantly in the advanced stage of HIV infection against the background of systemic manifestations and severe immunosuppression. Secondary neuroAIDS develops in the phase of symptomatic chronic HIV infection (stage of secondary diseases), which occurs in the period from 2 to 15 years from the moment of the first clinical manifestations. Certain neurological symptoms (headache, polyneuropathy, sleep disturbances, asthenia, depression, myopathy) can be caused by toxic antiretroviral therapy.

Aseptic meningitis

observed in 5-10% of patients with HIV. The clinical picture corresponds to acute serous meningitis. A distinctive feature is an increase in the level of CD8 lymphocytes in the cerebrospinal fluid, while in viral meningitis of other etiologies the number of CD4 lymphocytes increases. A more rare and severe form is acute meningoencephalitis, manifested by mental disorders, transient disturbances of consciousness (up to coma) and epileptic seizures.

Acute radiculoneuropathy

associated with acute inflammatory demyelination of the roots of the spinal and cranial nerves. Characterized by flaccid tetraparesis, polyneuritic type of sensitivity disorders, radicular syndrome, damage to the facial (less often oculomotor) nerves, bulbar disorders. The phase of increasing symptoms can last from several days to a month, then after 2-4 weeks of a stable condition, regression of symptoms begins. 70% of patients with this form of neuroAIDS experience complete recovery, 15% have severe residual paresis.

HIV encephalopathy

is the most common manifestation of primary neuroAIDS. Includes cognitive, behavioral and movement disorders. The latter are represented by cerebellar ataxia, tremor, pyramidal insufficiency, secondary parkinsonism, and hyperkinesis. Individual symptoms and mild cognitive deficits occur in approximately 75% of patients with AIDS. In 3-5% of patients, encephalopathy is the initial syndrome of neuroAIDS. The morphological substrate is multifocal giant cell encephalitis, affecting predominantly the frontal and temporal lobes, subcortical structures, pons and cerebellum.

HIV myelopathy

manifested by lower spastic paraparesis and pelvic disorders. It is characterized by a slow course and variability in the severity of clinical symptoms from mild paresis to severe plegia with urinary and fecal incontinence. This manifestation of neuroAIDS is observed in 20% of patients with HIV. Morphologically, vacuolation of the white spinal substance is revealed, most pronounced in the thoracic segments. However, changes are often not recorded on MRI of the spine.

Vascular neuroAIDS

is caused by vasculitis of the cerebral vessels and often leads to the development of ischemic stroke, the distinctive feature of which is a wave-like course and frequent transformation into a hemorrhagic stroke. TIAs preceding a stroke are typical, as well as recurrent strokes due to multifocal vascular lesions.

Symptoms of encephalitis

The disease usually begins with fever and headache, then the symptoms increase sharply and worsen - convulsions (fits), confusion and loss of consciousness, drowsiness and even coma are observed. Encephalitis can be seriously life-threatening.

Symptoms of encephalitis depend on many factors: the causative agent of the disease, its pathology, course and location.

The disease in many situations manifests itself as aches and pain. Moreover, these unpleasant symptoms affect the entire body: joints, muscles.

However, there are symptoms common to all types of encephalitis:

• headache - it is most often expressed in all areas of the head (diffuse), can be pressing, bursting;
• nausea and vomiting that does not bring relief;
• torticollis, tremor, seizures;
• the main symptom of encephalitis is a sharp rise in temperature to high values ​​(39–40°C);
• oculomotor disorders: ptosis (drooping of the upper eyelid), diplopia (double vision), ophthalmoplegia (lack of eyeball movements);
• Rarely, damage to the facial nerve is possible with the development of paresis of facial muscles, the trigeminal nerve with pain in the face, and isolated convulsions are possible.

Depending on the type of pathogen, the time interval between infection and the appearance of the first symptoms lasts from 7 to 20 days. During the latent period, the infection does not reveal itself; the presence of the pathogen can only be detected in a laboratory setting.

Other possible signs of encephalitis:

• increased muscle tone;
• involuntary movements (hyperkinesis);
• strabismus, impaired movements of the eyeballs (ophthalmoparesis);
• diplopia (double vision);
• ptosis (drooping) of the upper eyelid;

Another characteristic sign is muscle twitching in a person. These twitches occur involuntarily. It is important to note that sometimes a person is bothered by numbness of the skin, which manifests itself in different parts of the body.

Features of the clinical picture

Primary neuroAIDS often occurs without symptoms. In rare cases, neurological symptoms may appear 2-6 weeks after HIV infection. During this period, patients experience fever of unknown origin, swollen lymph nodes, and skin rashes. In this case the following appears:

1. Aseptic meningitis . Occurs in a small number of patients with HIV (about 10%). The clinical picture is similar to serous meningitis. With aseptic meningitis, the level of CD8 lymphocytes in the cerebrospinal fluid increases. When viral meningitis has another cause, the number of CD4 lymphocytes increases. In rare and severe cases, it can lead to mental illness and disturbances of consciousness.
2. Acute radiculoneuropathy . Caused by inflammatory selective damage to the myelin sheath of the roots of cranial and spinal nerves. This condition manifests itself in tetraparesis, sensitivity disorders of the polyneuric type, radicular syndrome, damage to the facial and optic nerves, and bulbar syndrome. Signs begin to appear and gradually become more intense both after a few days and after a few weeks. When the condition stabilizes for about 14-30 days, the intensity of symptoms begins to decrease. Only 15% of patients have sequelae after acute radiculoneuropathy.

Certain forms of neuroAIDS make themselves felt at the open stage of HIV infection:

1. HIV encephalopathy (AIDS dementia). The most common manifestation of neuroAIDS. The presence of behavioral, motor, and cognitive disorders is noted. In approximately 5% of HIV patients, encephalopathy is the primary symptom indicating the presence of neuroAIDS.
2. HIV myelopathy . It is expressed in dysfunction of the pelvic organs and lower spastic paraparesis. The peculiarity is the slow progression and differences in the severity of symptoms. About a quarter of people with HIV are diagnosed with this disease.

Treatment of encephalitis

An infectious disease doctor diagnoses and treats the disease in children and adults. If the diagnosis has been confirmed, the patient is immediately admitted to the hospital, to the infectious diseases department. Strict bed rest is indicated. The patient's condition is constantly monitored.

When treating encephalitis, specialists may be faced with the need to restore proper metabolism within the brain. For this purpose, the use of special vitamins, piracetam or polypeptides is prescribed. Among the anti-inflammatory drugs, salicylates and ibuprofen are often prescribed.

Symptomatic therapy:

• Antipyretic drugs
• Anti-inflammatory (glucocorticoids)
• Anticonvulsant therapy (benzonal, diphenine, finlepsin)
• Detoxification therapy (saline solutions, protein preparations, plasma substitutes)
• Resuscitation measures (ventilation, cardiotropic drugs)
• Prevention of secondary bacterial complications (broad-spectrum antibiotics)

To restore the normal functioning of the nervous system and rehabilitate consciousness, all kinds of biostimulants, antidepressants or tranquilizers are prescribed.

If the disease leads to impaired respiratory function, then artificial ventilation is performed. In addition, anticonvulsants and analgesics are prescribed.

Vaccines are the most effective way to reduce the risk of developing the disease. In this case, we are talking not only about vaccinations against tick-borne encephalitis, but also about the prevention of pathologies such as measles, etc.

Therefore, you should not neglect vaccination (vaccination) against certain types of encephalitis when traveling to areas with unfavorable conditions for this disease.

All encephalitis is treated in infectious diseases hospitals. In the chronic stage, it is necessary to regularly visit a neurologist, as well as take courses of medications aimed at improving brain activity and restoring ataxic and motor defects.

Pathologies of the nervous system in HIV

Damage to the nervous system during HIV infection can be primary or secondary. An attack on the nervous system can occur both at the initial stage of infection by the virus, and as a result of the development of severe immunodeficiency.

The primary lesion is characterized by the direct effect of the virus on the nervous system. This form of complication occurs in children with HIV.

Secondary lesions develop against the background of immunodeficiency. This condition is called secondary neuro-AIDS. Secondary lesions develop due to the addition of other infections, the development of tumors and other complications caused by immunodeficiency syndrome.

Secondary disorders can be caused by:

• autoimmune reaction of the body;
• the addition of an infection;
• tumor development in the nervous system;
• changes in vascular nature;
• toxic effects of drugs.

Primary damage to the nervous system during HIV infection may be asymptomatic. It should be noted that often damage to the nervous system is one of the first symptoms of HIV infection in a patient. In the early stages, the development of HIV encephalopathy is possible.

Peculiarities of children's symptoms

A child’s body differs from an adult in that the immune system is just being formed, so the body cannot cope with the human immunodeficiency virus. Against this background, the brain and central nervous system are the first to be affected.

If the baby was infected during labor or while he was inside the womb, then primary signs are detected approximately six months after birth (+/- 2 months).

The disease progresses rapidly and manifests itself as follows:

• mental and physical underdevelopment;
• digestive system disorders;
• development of purulent diseases;
• underweight

If symptoms are detected promptly and adequate treatment is provided, the baby can live for many more years.

NeuroAIDS classification

In accordance with the direct or indirect effects of HIV on the nervous system, it is customary to distinguish between primary and secondary neuroAIDS. The basic clinical forms that include primary neuroAIDS include: acute aseptic meningitis, HIV encephalopathy (AIDS dementia), HIV myelopathy (vacuolar myelopathy), vascular neuroAIDS, lesions of the peripheral NS (distal symmetric neuropathy, Guillain-Barre syndrome, multiple mononeuropathy, chronic inflammatory demyelinating polyneuropathy, cauda equina syndrome), muscle damage (myopathies).

Secondary neuroAIDS includes opportunistic neuroinfections and tumors. The former are distinguished by great diversity: cerebral toxoplasmosis, cryptococcal meningitis, herpesvirus neuroinfection (herpes zoster, cytomegalovirus and herpesvirus encephalitis, cytomegalovirus polyradiculopathy, herpesvirus myelitis and ganglioneuritis), progressive multifocal leukoencephalopathy, tuberculous lesions NS, neurosyphilis. The most common tumors of the central nervous system in neuroAIDS are: primary brain lymphoma, Burkitt's lymphoma, glioneuroblastoma, disseminated Kaposi's sarcoma.

Prevention

Preventive measures taken to prevent different types of encephalitis differ and are represented by the following activities:

1. Preventive measures that can, if possible, prevent infection with tick-borne and mosquito-borne encephalitis are preventive vaccinations of people living and/or working in areas of possible infection. Standard vaccination against tick-borne encephalitis includes 3 vaccinations and provides lasting immunity for 3 years.
2. Prevention of secondary encephalitis implies timely diagnosis and adequate treatment of infectious diseases.
3. Limiting tourist travel to countries where infection with viral encephalitis through mosquito bites is possible.

The disease AIDS is transmitted by a virus (HIV), which has lymphotropic and neurotropic properties. This means that the virus can harm the nervous system, causing diseases such as neuropathy, HIV encephalopathy, dementia, and psychosis.

Once in the human body, the virus spreads throughout the tissues within a few days. When the acute inflammatory phase subsides, the disease becomes a sluggish process that lasts several years. After the quiet stage, intensive replication of the virus begins. During this period, the stage of clinical manifestations of other diseases begins:

• fungal;
• bacterial;
• oncological

The immune system of an infected person is gradually destroyed. The disease ends in death after a few years.

Stages of dementia

Dementia develops over a long period and consists of several stages. However, not every patient goes through all stages; most cases experience mild cognitive impairment.

Normally, patients do not have any mental or motor impairment. This is an ideal case in which damage to the nervous system by the virus is not observed.

The subclinical stage is characterized by mild cognitive impairment, characterized by mood swings, depression and impaired concentration. Patients often experience slight inhibition of movement.

A mild form of dementia is characterized by slow mental activity, the patient speaks and moves slightly inhibited. The patient can fully care for himself without assistance, but complex intellectual or physical activities cause some difficulty.

The next stage of dementia development, middle, is characterized by impaired thinking, attention and memory. Patients can still look after themselves independently, but already have serious difficulties with communication and mental activity.

At a severe stage, the patient has difficulty moving without assistance. There is a severe disturbance in thinking, as a result of which any social interactions with others are very difficult. The patient does not perceive information and experiences serious difficulties when trying to talk.

The final stage of dementia development is vegetative coma. The patient is unable to perform basic actions and cannot cope without outside help.

Diagnostic methods

Since pathology causes a change in the volume of nervous tissue, the disease is diagnosed using the following methods:

• lumbar puncture;
• MRI;
• REG;
• Dopplerography.

Based on the lumbar puncture, a decision is made on the advisability of further research. This analysis reveals the presence of changes in the nervous system.

MRI (magnetic resonance imaging) can successfully identify pathological changes in the white matter of the brain. To obtain an accurate picture, it is necessary to conduct examinations of the brain, as well as the neck and eyeball.

REG (rheoencephalography) is an examination carried out by a non-invasive method, with the help of which it is possible to obtain complete information about the condition of the main arteries and vessels of the patient’s nervous system.

Dopplerography is mandatory. This examination is necessary to assess the condition of the blood vessels in the brain. Changes in encephalopathy primarily affect the main vertebral and cerebral arteries, changes in which are shown by Doppler ultrasound.

Causes of neuroAIDS

Despite the generally accepted neurotropism of HIV, the specific pathogenetic mechanisms of its effect on the nervous system (NS) are not completely clear. It is assumed that neuroAIDS is caused by both direct and indirect effects of the virus on the nervous system. The direct effect is associated with the tropism of HIV to CD4 receptors, which are found not only in the membrane of lymphocytes, but also in glial cells of the brain tissue.

The penetration of the virus through the blood-brain barrier (BBB) ​​is explained by an increase in the permeability of the latter against the background of a viral infection and the presence of the same CD4 receptors in the endothelial cells of the BBB. According to another hypothesis, the virus can be transferred to brain tissue along with macrophages that freely pass the BBB. NeuroAIDS is known to affect only glial cells; neurons that do not have CD4 receptors remain intact. However, since glial cells perform the role of “maintenance” of neurons, when they are damaged, the normal functioning of the latter is also disrupted.

The indirect effect of HIV occurs in several ways. Firstly, this is the development of opportunistic infections and tumor processes due to a sharp decrease in the immune status of the body. Secondly, they suggest the presence of autoimmune mechanisms (for example, in the development of aseptic meningitis and polyneuropathy in neuroAIDS) associated with the synthesis of antibodies to nerve cells that have an integrated HIV antigen. There is also a hypothesis about the neurotoxic effect of chemicals produced by HIV. In addition, the development of neuroAIDS is possible due to damage to the endothelium of cerebral vessels by proinflammatory cytokines, leading to microcirculation disorder and hypoxia, causing neuronal death.

It should be noted that the lack of complete clarity in the etiopathogenesis of HIV infection and neuroAIDS in particular, the presence of a significant number of false-positive reactions to HIV during its laboratory diagnosis, as well as difficulties in isolating the virus have led to the emergence among doctors and specialists in the field of immunology of people who consider it incompetent to concept of HIV infection. At the same time, supporters of HIV denial recognize the existence of immunodeficiency syndrome as such, but fear that with the introduction of the concepts of HIV infection and neuroAIDS, patients with various other diseases will fall under these diagnoses en masse.

Causes

Most often, encephalitis is caused by viruses - neuroinfections; sometimes it also occurs as complications of various infectious diseases.

A common cause of progression is neuroinfection. It is worth noting that the etiology of the disease directly depends on its type. Thus, the reasons for the progression of viral encephalitis are: the bite of infected insects (usually carried by mosquitoes or ticks), the penetration of influenza, herpes, and rabies viruses into the body.

Ways the virus enters the human body:

• insect bite (hematogenous route);
• with direct contact;
• nutritional route;
• airborne route.

Anyone can develop the disease, but older people and children are at greatest risk. People whose immune systems are suppressed or weakened by other factors, such as cancer treatment, HIV infection, or long-term use of steroids, are also prone to the disease.

Primary and secondary neuroAIDS

There are two groups of neurological manifestations that are associated with HIV infection: primary and secondary neuroAIDS.

In primary neuroAIDS, HIV directly affects the nervous system. There are several main manifestations of the primary form of the disease:

• aseptic meningitis;
• vacuolar myelopathy;
• vascular neuroAIDS;
• multiple mononeuropathy;
• facial nerve neuropathy;
• Guillain-Barre syndrome;
• acute meningoencephalitis;
• damage to the peripheral nervous system;
• sensory polyneuropathy;
• AIDS dementia;
• inflammatory demyelinating polyneuropathy.

Secondary neuroAIDS is caused by opportunistic infections and tumors that develop in an AIDS patient.

Secondary manifestations of the disease are expressed as follows:

• cerebral toxoplasmosis;
• cryptococcal meningitis;
• herpesvirus neuroinfection (herpesvirus encephalitis, myelitis, ganglioneuritis, cytomegalovirus encephalitis, polyradiculopathy);
• progressive multifocal leukoencephalopathy;
• lesions of the nervous system of a syphilitic nature;
• tuberculosis of the nervous system.

Most often, patients with neuroAIDS have the following tumors in the central nervous system:

• disseminated Kaposi's sarcoma;
• Burkitt's lymphoma;
• ganglioneuroblastoma;
• primary brain lymphoma;
• undifferentiated tumors.

Treatment

No existing treatment can completely cure the neurological complications of AIDS. Some complications require intensive care, while others require symptomatic treatment.

Neuropathic pain is often difficult to control. The following medications are used: analgesics, antiepileptic drugs and some classes of antidepressants. Damaged tissue can put pressure on nerves, causing pain. Inflammatory and autoimmune conditions that lead to neuropathy can 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 neuropsychiatric or psychotic disorders include antidepressants and anticonvulsants. Psychostimulants may also improve depressive symptoms and combat lethargy. Benzodiazepines may be prescribed to treat anxiety. Psychotherapy may also be effective for some patients.

Aggressive antiretroviral therapy is used to treat AIDS dementia, 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 onset of some infections.

Other treatment options for neuro-AIDS include physical therapy and rehabilitation, radiation therapy and/or chemotherapy to kill or shrink cancerous brain tumors that may be caused by the HIV virus, antifungal or antimalarial drugs to fight some bacterial infections associated with the disorder , and penicillin for the treatment of neurosyphilis.
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Causes and pathogenesis of the disease

The pathogenetic mechanisms of the effects of HIV on the nervous system have not yet been fully studied. It is believed that neuroAIDS occurs due to direct and indirect effects on the nervous system.

There is also an opinion that the reason lies in impaired regulation of the response process from the immune system. The direct effect on the nervous system is carried out through penetration into cells that carry the CD4 antigen, namely neuroglia of the brain tissue, cells of the lymphocyte membrane.

At the same time, the virus can penetrate the blood-brain barrier (the physiological barrier between the circulatory system and the central nervous system). The reason for this is that viral infection increases the permeability of this barrier, and that its cells also have CD4 receptors.

It is believed that the virus can penetrate brain cells through cells that can capture and digest bacteria that easily pass the blood-brain barrier. As a result of this, only neuroglia are affected, while neurons, due to the fact that they do not have CD4 receptors, are not damaged.

However, due to the fact that there is a connection between glial cells and neurons (the former serve the latter), the function of neurons is also impaired.

As for the indirect influence of HIV, it occurs in various ways:

• as a result of a rapid decrease in immune defense, infections and tumors develop;
• the presence in the body of autoimmune processes that are related to the production of antibodies to nerve cells that have built-in HIV antigens;
• neurotoxic effects of chemicals produced by HIV;
• as a result of damage to the endothelium of cerebral vessels by cytokines, which leads to disturbances in microcirculation, hypoxia, which causes the death of neurons.