AIDS neurological damage

Introduction to AIDS neurological damage AIDS (acquired immunodeficiency syndrome), also known as acquired immunodeficiency syndrome, is a contagious disease caused by human immunodeficiency virus (HIV). In 1981, the first AIDS patient was discovered in the United States. Two patients in China were reported in 1989 and 1991. The AIDS patients are usually referred to as AIDS patients, and those who are not ill are AIDS-infected. Source of infection of nervous system damage. HIV is a neurotropic virus that invades the nervous system early in the disease, so the central nervous system manifestation of AIDS is mainly caused by direct HIV invasion. Secondly, after the HIV infection, the human immune mechanism is inhibited or the immune deficiency causes the virus, bacteria. , fungi and other susceptible to infection or secondary tumors, the combination of the above two reasons is more likely to suffer from diseases. basic knowledge The proportion of illness: 0.001% Susceptible people: no specific people Mode of transmission: sexually transmitted mother-to-child transmission of blood transmission Complications: multiple system organ failure

AIDS neurological damage causes

(1) Causes of the disease

HIV is one of the subfamilies of the retrovirus family of lentiviruses, including HIV-1 and HIV-2. HIV-1 is more potent and pathogenic than HIV-2 and is the main pathogenic microorganism. At present, HIV-2 infection is mainly limited to AIDS patients in some countries in West Africa, and the mechanism of AIDS is still unclear. The HIV-1 virus itself and its metabolites have direct pathogenic effects. The main feature of HIV-1 activity is that The genomic RNA is reverse transcribed into double-stranded DNA, which is then transferred into the host cell nucleus. It is integrated into the host chromosome by integrase to form a long-lasting structure. The body cannot remove it. It can remain stationary without activity. High gene expression performance and active participation in virus production, HIV-1 also has neurotropic characteristics, can rely on mutations to obtain neurotropic specific variants, HIV can survive long-term survival in the central nervous system, and directly infected and cause many damage At the same time, HIV-1 does not always lead to cell death, so nerve tissue can be used as a place for virus storage.

(two) pathogenesis

The characteristic pathophysiological changes of AIDS are severe immunodeficiency. HIV-1 binds to CD4-positive cells through a glycoprotein gp120 on its membrane. CD4 is a receptor for gp120, and mainly CD4-positive cells in humans. Helper T cells (Th), after HIV-1 enters the cell, as the virus continues to replicate, it is destroyed by the mechanism of apoptosis, resulting in the inverse of the Th/Ts ratio in the body, causing serious immunodeficiency, making the body Many opportunistic infections and susceptibility to certain tumors increase and eventually the patient dies.

It is confirmed that only blood, semen and cervical secretions can infect AIDS, so the main routes of transmission are: 1 sexual contact transmission; 2 blood transmission; 3 mother-to-child transmission, of which homosexual and intravenous drug dependence account for the vast majority.

AIDS neurological damage prevention

The main problem of AIDS is to prevent infection. Once the infection is serious, it is necessary to cut off three main routes of transmission, such as sexual contact, blood transmission and mother-to-child transmission, to reduce the incidence.

AIDS neurological damage complications Complications, multiple system organ failure

Because HIV is the causative agent of AIDS, once the body is infected, it will cause damage to the immune system. Therefore, AIDS will cause opportunistic infections and tumors of various causes during the onset of the disease, and the comorbidities Can be secondary to comorbidities, such as Kaposi sarcoma can be combined with central nervous system infection, AIDS patients due to low immune function, especially late, not only often secondary to other diseases, but also can cause multiple organ failure (MOSF), secondary metabolic encephalopathy .

Symptoms of AIDS neurological damage Common symptoms Loss of appetite, high fever, nausea and vomiting, lymphadenopathy, diarrhea, convulsions, sensory disturbance

HIV is a neurotropic virus that invades the nervous system early in the disease, so the central nervous system manifestation of AIDS is mainly caused by direct HIV invasion. Secondly, after the HIV infection, the human immune mechanism is inhibited or the immune deficiency causes the virus, bacteria. , fungi and other susceptible to infection or secondary tumors, the combination of the above two reasons is more likely to suffer from diseases.

1. Primary neurological diseases of AIDS The central nervous system caused by HIV can be inflammatory, demyelinating or degenerative, and several of them are considered to be definitive lesions of AIDS.

(1) HIV aseptic meninges (brain) inflammation: seen in the early stage of AIDS, also seen in the late stage, the main symptoms of the patient are headache, fear of light, nausea, vomiting, fever, sore throat, loss of appetite, diarrhea, etc. There are obvious symptoms of encephalitis, such as convulsions, aphasia, etc., often with general body rigidity - clonic seizures, lymphocytes in the cerebrospinal fluid may increase, protein is elevated, sugar is normal, EEG shows diffuse abnormalities, and some patients There may be cranial nerve palsy, the most common is the facial nerve, followed by the trigeminal nerve or the auditory nerve.

(2) AIDS dementia syndrome: formerly known as subacute or chronic HIV encephalitis, the most common in clinical, generally occurs in the late stage of the disease, mainly characterized by progressive cognitive decline, inattention, memory loss , time and space orientation disorder, motor function weakened, behavioral abnormality, difficulty in walking due to ataxia and tremor, writing failure, poor balance function, etc., such as spinal cord involvement, increased muscle tone, hyperreflexia, sensory disturbance, In the late stage, there may be loss of control of the bowel movements, behavior changes such as apathy, lack of interest, depression, silence, etc. As the disease progresses, the patient gradually develops toward the direction of plant survival. Unlike the dementia caused by poisoning or metabolic disorders, the above symptoms appear. It occurs under the condition of conscious consciousness. There is no special diagnostic criteria for this syndrome. It is very important to detect the slight cognitive decline of the patient. The head CT and MAI examinations often have brain atrophy, and the HIV virus can be found in the cerebrospinal fluid. Confirmed, there is no specific treatment for this syndrome.

(3) acute granulomatous cerebral vasculitis: extensive anterior, middle, posterior and proximal branches of the granuloma inflammatory changes, causing most cerebral infarction, involving the basal ganglia, internal capsule, subcortical white matter, parietal lobe And occipital cortex and pons are covered, clinical symptoms have high fever, mental symptoms, paroxysmal dysfunction and corresponding focal symptoms, CT showed progressive brain atrophy and multiple low-density lesions, cerebrospinal fluid and brain biopsy HTLV- III culture was positive, but blood culture and 3 serum HTLV-III antibodies were negative, suggesting that infection is limited to the central nervous system.

(4) vacuolar myelopathy: can occur alone or in combination with AIDS dementia syndrome, characterized by the discovery of vacuoles in the white matter of the spinal cord, mainly invading the lateral and posterior cords, with the chest vein being the most obvious, showing a similar Acute combined degeneration, for progressive spastic paraplegia, ataxia and urinary incontinence, some patients also have vacuolar changes in the brain, clinical manifestations of progressive dementia.

(5) peripheral neuropathy (multiple radiculitis, polyneuritis and neuropathy): about 15% of AIDS with peripheral nerve damage, often manifested as distal symmetric sensory motor neuropathy, may have painful paresthesia, There are also chronic Guillain-Barre type neuropathy, some cases with subacute encephalopathy, normal cerebrospinal fluid or protein, electromyography showing acromegaly, with demyelination and mild nerve conduction velocity Slow down.

2. The central nervous system opportunistic infection secondary to AIDS The central nervous system is the second organ other than the lung that is susceptible to conditional infection.

(1) Toxoplasmosis: Toxoplasma gondii is a protozoan in the cell, which can cause multifocal, scattered necrosis and inflammatory abscess in the central nervous system. It is more common in the basal junction and is a toxoplasma that lurks in the central nervous system. Reactivation can also occur in other immunosuppressive states, manifested as hypothermia, altered state of consciousness, convulsions and localized signs, but symptoms and signs are not typical, and must be differentiated from other intracranial space-occupying lesions and lymphomas. Imaging findings of enhanced multiple ring lesions, surrounded by edema and mass effect, basal node involvement is the most common, serological diagnosis is often non-specific, but other diagnostics should be considered when titer < 1:4, MRI is most sensitive, However, it can not be used for differential diagnosis. Brain biopsy can be quickly diagnosed, and pyrimethamine and sulfadiazine are supplemented daily with folic acid (to prevent anemia); hormones are used with caution because it can inhibit the immune function that has been impaired.

(2) Giant cell encephalitis and retinitis: the incidence is uncertain, and it can be confused with HIV encephalitis in clinical manifestations, but the disease progresses rapidly, there is obvious periventricular inflammation or in cytomegalovirus retinitis and whole body broadcasting. The symptoms of cerebral inflammation should be considered under the condition of sporadic infection. The degree of pathological changes varies from a small amount of cytomegalovirus inclusions to obvious encephalitis and meningoencephalitis. Biopsy can find evidence of the presence of virus in the brain, but It is rarely isolated, cerebrospinal fluid culture is often negative, imaging examination shows abnormalities of white matter around the ventricles, enhanced scanning can show cortical and subcortical lesions, giant cell retinitis is a common ophthalmic infection in AIDS patients, 20% of hemorrhagic Retinitis, 60% of the bilateral, can lead to blindness without treatment.

(3) Cryptococcus neoformans meningitis: the bacteria enter the body through the lungs, and finally reach the brain, the clinical manifestations of progressive headache aggravation and disturbance of consciousness, accompanied by fever and epileptic seizures, neck stiffness is not common, cerebrospinal fluid cells often do not increase, CT findings are non-specific, mild to moderate ventricle dilatation, no meningeal enhancement, sometimes visible brain atrophy, granuloma or abscess imaging, diagnosis depends on cerebrospinal fluid ink stain to find pathogens, if not treated can die within a few weeks, if Early diagnosis can be treated with a combination of amphotericin B and 5-fluorocytosine.

(4) bacterial infection: more common with mycobacterial infection, it has been recognized that tuberculosis is the most common opportunistic infection in serum HIV-1 positive patients, and its clinical manifestations are abnormal in patients with HIV and tuberculosis. The progress is accelerated, but tuberculosis is often innocent. Due to the weakened response, HIV patients have no significant increase in tuberculosis test. The type of extrapulmonary tuberculosis is different from that of general tuberculosis patients. Lymph node enlargement and miliary tuberculosis are the most common.

3. Central nervous system tumor secondary to AIDS

(1) Primary central nervous system lymphoma: Primary central nervous system malignant lymphoma is extremely rare, the incidence rate in the normal population is estimated to be 0.0001%, while in AIDS patients is as high as 2%, the US primary central nervous system lymphoma There are about 225 cases per year. Therefore, the disease will become the main disease of AIDS patients. The tumor cells infiltrate the perivascular space of the brain parenchyma or the pia mater. The clinical manifestations are mostly subacute onset, mental state changes, headache, confusion, vision. Obstruction, focal neurological dysfunction, etc., meningeal metastasis may have cranial nerve damage with multiple nerve root damage, etc. CT shows deep brain, interstitial nodules or ring-enhanced lesions around the ventricle, difficult to with other tumors or infections Identification, invasion of the meninges may have meningeal thickening and enhancement, usually require brain biopsy to confirm the diagnosis, recent practice has proved that the tumor is sensitive to radiotherapy, it should be active radiation therapy as soon as possible, can extend the patient's survival.

(2) Kaposi sarcoma: the most common malignant tumor of AIDS patients, but the central nervous system rarely occurs. When the central nervous system is involved, it has been combined with other visceral involvement and extensive lung metastasis. Clinically, there may be focal symptoms. CT has Focal damage, and easy to merge with central nervous system infection, although it is sensitive to radiation, the patient eventually died of extensively metastatic Kaposi sarcoma.

4. Secondary cerebrovascular accident 10% to 20% of AIDS patients may have cerebrovascular accidents, the most common is multiple focal ischemic cerebral infarction, can also be manifested as hemorrhagic cerebral infarction, intratumoral hemorrhage, short-lived Ischemic attack and epidural, subdural hematoma, subarachnoid hemorrhage, cerebral hemorrhage, etc. Recently, blood factors that can produce hypercoagulable state have been isolated from the blood of some AIDS-infected people, which may be caused These young AIDS patients frequently cause ischemic cerebral infarction.

AIDS neurological damage examination

1. Detection of HIV antibody The first expression of p24 antigen after HIV infection gradually disappears after several weeks, but antibodies against the surface proteins of viruses such as p24 and gp41 gradually appear, and when an antibody is detected, a virus is considered to exist.

2. Antigen detection ELISA double-antibody sandwich method can detect p24 antigen in serum and cerebrospinal fluid. The former is beneficial to determine the antigenemia of acute infection, and the latter is beneficial to the diagnosis of dementia syndrome.

3. PCR technology can detect trace amounts of viral DNA, and the autoradiography method can also observe the presence of the virus.

4. Cerebrospinal fluid examination includes smear staining, virus isolation and culture, determination of antigen-antibody titer, and thereby determination of the type of infection and virion.

5. Brain biopsy For patients with suspected AIDS in the brain, the biopsy site can be confirmed by CT and MRI, and the diagnosis is confirmed.

6. CT scan is a widely used examination method. CT examination shows that about 35% of AIDS patients have simple brain atrophy, 25% have focal brain damage, HIV encephalopathy, fungal meningitis is more normal, scanning abnormalities can be seen in the bow Insect diseases (50% to 70%), others such as primary central nervous system lymphoma (10% to 25%), progressive multifocal leukoencephalopathy (PML) (10% to 22%); low density If the enhancement is not obvious, it may be PML or primary central nervous system lymphoma; the lesion is limited to white matter, suggesting PML; central nervous lymphoma may have a mass effect; there are ring enhancement, especially the lesion is located in the basal ganglia. The suggestion is toxoplasmosis; progressive brain atrophy is a complex syndrome of dementia. After treatment, CT review can help to observe the efficacy and prognosis.

7. MRI images are sensitive to early brain disease changes, more accurate than CT examination, especially when CT can only show a single lesion, MRI may suggest more lesions, toxoplasmosis is usually bilateral multiple intracranial abnormalities, if MRI The disease can be excluded only when a single lesion is displayed.

8. EEG AIDS encephalopathy can show that the basic rhythm is slow (7 ~ 7Hz), Toxoplasma lymphoma is mainly caused by focal changes, and the EEG can be improved after treatment of the disease.

9. Other examinations may be based on different parts of the lesion, using different examination methods, such as electromyography, cerebral angiography and other special examinations to help diagnose.

Diagnosis and diagnosis of AIDS neurological damage

Diagnostic criteria

The US Centers for Disease Control's reporting criteria for AIDS is: past health, no known potential factors other than HIV infection, and cellular immunodeficiency, resulting in concurrent opportunistic infections (Pneumocystis carinii or other specific opportunistic infections) or Some malignant tumors (most commonly Kaposi sarcoma), in other words, a complete AIDS in addition to HIV infection caused by cellular immune defects, patients must have one or several secondary diseases caused by cellular immune defects to diagnose, clinically There are often some patients who have some manifestations of HIV infection and cellular immunodeficiency, such as unexplained fever, insidious weight loss, severe oropharyngeal candidiasis, etc., but there are no other secondary diseases, called Acquired AIDS related complex (ARC) or pre-AIDS.

In 1990, the diagnostic criteria of the Ministry of Health of China were:

1. The serum of the HIV-infected person is tested by screening test, such as immunoenzymatic method or indirect immunofluorescence test, and then confirmed by Western blot and other methods.

2. Confirmed cases

(1) HIV antibody positive, and any of the following, can be experimentally diagnosed AIDS patients:

1 Recently (3 to 6 months) weight loss of more than 10%, and continued fever above 38 ° C for at least 1 month.

2 Recently (3 to 6 months) weight loss of more than 10%, and continued diarrhea (3 to 5 times a day) more than 1 month.

3 Pneumocystis carinii pneumonia, Kaposi sarcoma.

4 obvious fungal or other conditional pathogen infections.

(2) If the antibody-positive person has weight loss, fever, and diarrhea symptoms close to the above first standard and has one of the following, it can be an experimentally diagnosed AIDS patient:

The 1CD4+/CD8+ lymphocyte count ratio was <1, and the CD4+ cell count was decreased.

2 lymph nodes.

3 obvious symptoms and signs of central nervous system occupying lesions, obvious dementia, loss of discrimination, or motor neurological dysfunction.

Differential diagnosis

1. Clinically, the differential diagnosis of encephalitis, spinal cord, nerves and muscles should be asked in detail, and the possibility of AIDS should be carefully identified.

2. The clinical manifestations of neurological diseases caused by AIDS are complex and changeable. Under certain conditions, AIDS patients may be combined with toxoplasmosis, herpes simplex, tuberculosis, syphilis, etc., and there may be more than two kinds of damages, such as AIDS dementia combined with myelopathy, AIDS patients may have similar symptoms in several types of lesions, such as intracranial space-occupying lesions, should consider both toxoplasmosis, tuberculous granuloma, fungal granuloma, bacterial brain abscess, Primary lymphosarcoma and the like.

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