AIDS
Introduction
Introduction to AIDS AIDS, the acquired immunodeficiency syndrome, English name AcquiredImmuneDeficiencySyndrome, AIDS. It is a syndrome caused by human immunodeficiency virus (Human Immunodeficiency Virus, HIV), which is accompanied by a series of opportunistic infections and tumors, which can lead to death. At present, AIDS has become a public health problem that seriously threatens the health of the people of the world. It targets the most important T4 lymphocytes in the human immune system, phagocytizes a lot, destroys T4 lymphocytes, destroys the human immune system, and eventually collapses the immune system, causing the body to become ill due to loss of resistance to various diseases. And died. Scientists call this virus "human immunodeficiency virus." The incubation period of HIV in the human body averages 12 to 13 years. It looks normal before it develops into an AIDS patient. They can live and work without any symptoms for many years. basic knowledge The proportion of sickness: 0.00001% (especially for gay men) Susceptible population: The incidence of young adults is more than 80% of the age of onset is 18-45 years old. Public health workers, accompanied by illegal sex workers and drug injectors. Mode of infection: 1, sexual contact spread 2, blood transmission 3, mother-to-child transmission 4, spread of shared needles Complications: anemia, diarrhea, dementia, congestive heart failure, interstitial nephritis, rheumatoid arthritis, polymyositis, hypotension, diabetes, adrenal crisis
Cause
AIDS cause
Etiology:
HIV belongs to the human lentivirus group of the retrovirus genus Lentivirus, and is classified into type 1 and type 2. HIV-1 is currently prevalent worldwide. HIV-1 is a spherical particle with a diameter of about 100-120 nm and consists of two parts, the core and the envelope. The core consists of two single-stranded RNA strands, core structural proteins, and enzymes necessary for viral replication, containing reverse transcriptase, integrase, and protease. HIV-1 is a highly variable virus, and irregular antiviral therapy is an important cause of viral resistance. HIV-2 is mainly found in West Africa and is currently found in the United States, Europe, South Africa, and India. The ultrastructure and cellular tropism of HIV-2 is similar to that of HIV-1, and its nucleotide and amino acid sequences are significantly different from those of HIV-1.
HIV is less viable in the external environment and less resistant to physical and chemical factors. Sensitive to heat, HIV can be completely inactivated by treatment at 56 ° C for 30 minutes and 100 ° C for 20 minutes. Pasteurization and the usual concentrations of most chemical disinfectants can inactivate HIV. For example, 75% alcohol, 0.2% sodium hypochlorite, 1% glutaraldehyde, 20% acetaldehyde and acetone, ether and bleaching powder can inactivate HIV. But ultraviolet or gamma rays cannot inactivate HIV.
Epidemiology:
1. Epidemic profile: WHO reported that in 2010, there were 34 million surviving HIV carriers and AIDS patients worldwide, with a new infection of 2.7 million and a death of 1.8 million people throughout the year. More than 7,000 new infections occur every day, and are prevalent throughout the world, but more than 97% are in low- and middle-income countries, especially in Africa. Experts estimate that the world's most polluted areas may move from Africa to Asia. China's CDC estimates that as of the end of 2011, there were about 780,000 HIV-positive carriers and AIDS patients in China, with 48,000 new infections and 28,000 deaths. The epidemic has covered all provinces, autonomous regions, and municipalities directly under the central government. At present, China is at the peak of AIDS epidemics and deaths, and has begun to spread to high-risk groups such as drug users and sputum.
2. Sources of infection: HIV-infected and AIDS patients are the only source of infection.
3. Route of transmission: HIV is mainly found in the blood, semen, vaginal secretions, and milk of infected people and patients. 1 Sexual behavior: Unprotected sexual behavior with infected partners, including same-sex, heterosexual, and bisexual contact. 2 intravenous drug use: sharing the unsterilized injection tool used by infected people with others is a very important route of HIV transmission. 3 Mother-to-child transmission: During pregnancy, production and breastfeeding, HIV-infected mothers may spread to the fetus and the baby. 4 blood and blood products (including artificial insemination, skin transplantation and organ transplantation). Handshake, hugs, courtesy kisses, eating and drinking, sharing toilets and bathrooms, shared office, public transport, entertainment facilities, etc., will not spread HIV.
4. Susceptible people: The population is generally susceptible. High-risk groups include: gay men, injecting drug users, people who are often sexually exposed to HIV carriers, those who regularly transfuse blood and blood products, and those born to HIV-infected mothers.
Pathological changes:
(1) Pathological changes of the immune system: including HIV-associated lymphadenopathy, high depletion of spleen lymphocytes, premature thymic degeneration in children, and reduction of bone marrow cells in patients with advanced disease.
(B) clinical case changes: AIDS is a disease involving the body's multiple organ system, skin and mucous membranes, lymph nodes, eyes, respiratory system, digestive system, nervous system, urinary system. In addition to immune system diseases, it also includes multi-system opportunistic infections (such as viruses, bacteria, fungi and protozoa) and malignant tumors (including Kaposi's sarcoma, malignant lymphoma and cervical cancer), which constitute a complex clinical pathological change of AIDS.
Pathogenesis
(a) the process of viral infection
Primary infection
HIV requires access to cells by means of receptors on the surface of susceptible cells, including the first receptor and the second receptor. After entering the human body, HIV reaches the local lymph nodes within 24-48 hours, and the viral components can be detected in the peripheral blood in about 5 days. In turn, viremia is produced, leading to an acute infection.
2. The process of HIV infection in human cells
Adsorption and penetration: After HIV-1 is infected, it selectively adsorbs to the CD4 receptor of the target cell and enters the host cell with the help of the helper receptor. Mature virus particles are formed by cyclization and integration, transcription and translation, assembly, maturation and budding.
3. Three clinical outcomes after HIV infection
Since the body's immune system cannot completely eliminate the virus and form a chronic infection, it can be clinically manifested as three types of outcomes: typical progressors, rapid progressors, and long-term non-progressors.
(two) anti-HIV immune response
Anti-HIV immune responses include specific immune and non-specific immune responses, with a specific immune response. Including specific humoral immunity and specific cellular immunity, the human immune system mainly through various specific antibodies against HIV proteins, specific CD4+ T lymphocyte immune responses and CTL directly or secrete various cytokines (such as tumor necrosis factor, interference Prime, etc.), inhibit viral replication.
(three) immunopathology
1. The number of CD 4+ T lymphocytes decreased
The number of CD4+ T lymphocytes in the body is reduced after infection with HIV. It is divided into three stages: 1 acute infection period: the number of CD4+ T lymphocytes decreases rapidly in the short term, and most infected people have no special treatment, the number of CD4+ T lymphocytes Can self-recover to normal or near normal level; 2 asymptomatic infection period: the number of CD4+ T lymphocytes continues to decrease slowly, mostly between 800 ~ 350 / mm3, this period lasts for several months to ten years, the average duration About 8 years; 3 symptomatic period: CD4+ T lymphocytes decreased again rapidly, mostly below 350/mm3, and some advanced patients fell below 200/mm3, and decreased rapidly.
2. CD4+ T lymphocyte dysfunction
Mainly manifested as T helper 1 (Th1) cells replaced by T helper 2 (Th2) cells, impaired function of antigen-presenting cells, decreased production of interleukin-2 and loss of activation of antigenic response, making HIV/AIDS patients It is prone to various infections.
3. Abnormal immune activation
After HIV infection, CD4+ and CD8+ T lymphocytes expressed abnormal levels of immune activation markers such as CD69, CD38 and HLA-DR. Abnormal immune activation can not only measure changes in plasma viral load, but also predict the rate of CD4+ T lymphocyte reduction.
4. Immune reconstruction
After the antiviral treatment, the abnormal immune changes caused by the above-mentioned HIV can return to normal or near normal levels, the incidence of various opportunistic infections and tumors related to AIDS is reduced, and the mortality and morbidity of AIDS patients are reduced. However, anti-HIV treatment does not enable all AIDS patients to achieve immune reconstitution, nor can it re-establish the anti-HIV CD4+ T lymphocyte-specific immune response, and the ability of CD8+ T lymphocytes to specifically anti-HIV is also reduced, which means that patients need to maintain medication for a long time. .
Prevention
AIDS prevention
Strengthen self-protection awareness: understand HIV; don't engage in unprotected sex, use condoms; don't share needles with others, use sterile syringes; use blood products carefully.
First, specific prevention
(1) With the 1993 US CDC classification diagnostic criteria, the scope of diagnosis of AIDS has been expanded to facilitate the prevention and treatment of AIDS, and certain drugs are administered according to CD4 T lymphocyte reduction;
(2) AIDS vaccine: The United States conducted a second phase of 296 trials on two AIDS vaccines containing gp120. Since 6 people have contracted and temporarily terminated, Thailand is conducting UBI synthetic vaccine trials;
(3) Blocking mother-to-child transmission: CD4+T lymphocytes>; 200/l of AIDS pregnant women, with AIT in prenatal, intraoperative and infant treatment, have a certain protective effect.
Second, comprehensive prevention
(1) Popularize the prevention knowledge of AIDS, understand the route of transmission, clinical manifestations and prevention methods;
(2) Strengthening moral education and prohibiting promiscuity, especially with foreigners, and banned secrets;
(3) Avoid sexual contact with HIV-infected persons, AIDS patients and high-risk groups;
(4) It is forbidden to share syringes and needles with intravenous drug concealers;
(5) When using imported blood, blood components and blood products, HIV testing must be carried out;
(6) Domestic blood donors are strictly selected, and HIV-negative prescriptions should be gradually tested to provide blood supply to prevent HIV transmission;
(7) Blood donation, organ donation, organization and semen should be tested for HIV;
(8) Establishing an AIDS testing center;
(9) Promote the use of condoms and avoid anal sex;
(10) AIDS or HIV-infected persons should avoid pregnancy, and infants should avoid breastfeeding.
Complication
AIDS complications Complications anemia diarrhea dementia congestive heart failure interstitial nephritis rheumatoid arthritis polymyositis hypotension diabetes adrenal crisis
AIDS patients often have significant weight loss and severe malnutrition, anemia, white blood cells, platelets or whole blood cells.
Long-term diarrhea causes water and electrolyte disturbances, and nervous system damage causes mental decline, unresponsiveness, depression, anxiety, paranoid mental illness or dementia.
Cardiovascular damage causes tachycardia, enlarged heart, and congestive heart failure.
Injury of renal function can cause interstitial nephritis and tubular necrosis, proteinuria, oliguria, high edema, azotemia and renal failure.
Musculoskeletal system damage can cause migratory arthritis, joint pain and joint fluid accumulation, similar to rheumatoid arthritis, anti-rheumatic treatment is not good, can also show polymyositis, muscle tenderness and movement disorders, Muscle biopsy showed necrotizing myositis.
Endocrine system damage can occur adrenal insufficiency and hyporeninemia, hypotension, persistent hyponatremia and hyperkalemia, hypothyroidism, diabetes and adrenal crisis.
Symptom
AIDS symptoms common symptoms inflammatory night sweat HIV infection abdominal pain hypoxemia high fever diarrhea fever sputum sepsis
China divides HIV infection into acute phase, asymptomatic phase and AIDS phase.
(1) Acute phase
It usually occurs about 2-4 weeks after the initial infection with HIV. The main clinical manifestations are fever, sore throat, night sweats, nausea, vomiting, diarrhea, rash, joint pain, swollen lymph nodes and nervous system symptoms. Most patients have mild clinical symptoms and remission after 1-3 weeks.
In this period, HIV-RNA and P24 antigens are detected in the blood, while HIV antibodies appear only a few weeks after infection. The CD4+ T lymphocyte count was transiently reduced and the CD4/CD8 ratio was inverted.
(2) Asymptomatic period
This period can be entered directly from the acute phase, or without obvious acute phase symptoms.
The duration of this period is generally 6-8 years. But there are also rapid progress and long-term non-progress. The length of this period is related to the number of viruses, the type of infection, the route of infection, and the immune status of the body.
(3) AIDS period
The final stage after infection with HIV. The patient's CD4+ T lymphocyte count decreased significantly, more than <200/mm3, and the HIV plasma viral load increased significantly. The main clinical manifestations of this period are HIV-related symptoms, various opportunistic infections and tumors.
HIV-related symptoms: mainly manifested as fever, night sweats, diarrhea lasting more than one month; weight loss of more than 10%. Some patients present with neuropsychiatric symptoms such as memory loss, mental apathy, personality changes, headache, epilepsy and dementia. In addition, persistent systemic lymphadenopathy may occur, characterized by 1. lymph node enlargement in two or more sites other than the groin; 2. lymph node diameter 1 cm, no tenderness, no adhesion; 3 duration 3 More than a month.
Common symptoms of HIV-related opportunistic infections and tumors: fever, night sweats, swollen lymph nodes, cough, sputum, hemoptysis, dyspnea, headache, vomiting, abdominal pain, diarrhea, gastrointestinal bleeding, difficulty swallowing, loss of appetite, leukoplakia and ulcers, each A kind of rash, vision loss, blindness, dementia, epilepsy, limb paralysis, weight loss, anemia, incontinence, urine retention, intestinal obstruction, etc.
Examine
AIDS check
Laboratory inspection
(1) Mainly moderate to above cellular immunodeficiency including: CD4+ T lymphocyte depletion: decreased T lymphocyte function, significant decrease in peripheral blood lymphocytes, CD4<;200/l, CD4/CD8<;1.0, (normal human 1.25 to 2.1), delayed type hypersensitivity skin test was negative, and mitogen stimulation was low.
(2) B lymphocyte dysfunction: polyclonal hyperglobulinemia, circulating immune complex formation and autoantibody formation.
(3) NK cell activity decreased.
(4) Pathogen examination of various pathogenic infections such as PCR, histologically confirmed malignant tumors such as KS.
(5) HIV antibody detection:
1. Enzyme-linked immunosorbent assay (ELISA);
2. Gelatin particle agglutination test (PA);
3. Immunofluorescence assay (IFA);
4. Western Blot (WB method);
5. Radioimmunoprecipitation (RIP), in which the first three are commonly used in screening tests and the latter two are used to confirm the test.
(6) PCR technology to detect HIV virus.
Diagnosis
AIDS diagnosis and identification
Diagnostic criteria
1. HIV-positive, and any of the following, can be diagnosed for AIDS patients.
(1) In the near future (3-6 months), the weight loss is more than 10%, and the continuous fever reaches 38 °C for more than one month;
(2) In the near future (3-6 months), the weight loss is more than 10%, and the diarrhea is continued (3-5 times a day) for more than one month.
(3) Pneumocystis carinii pneumonia (PCR)
(4) Kaposi sarcoma KS.
(5) Significant mold or other conditions causing infection.
2. If the antibody-positive person has weight loss, fever, and diarrhea symptoms close to the above item 1, the AIDS patient can be diagnosed experimentally.
(1) CD4/CD8 (assisted/inhibited) lymphocyte count ratio <1, CD4 cell count decreased;
(2) systemic lymphadenopathy;
(3) Significant symptoms and signs of central nervous system occupying lesions, dementia, loss of discriminating ability, or motor neurological dysfunction.
Differential diagnosis
Need to be identified with the following diseases:
First, the primary immunodeficiency disease.
Second, secondary immunodeficiency disease, corticosteroids, chemotherapy, radiotherapy or malignant tumors and other secondary immune diseases.
, idiopathic CD4+ T lymphopenia, resembles AIDS, but no HIV infection.
Fourth, autoimmune diseases: connective tissue disease, blood diseases, etc., AIDS has fever, weight loss needs to be identified with the above diseases.
Five, lymphadenopathy: such as KS, He Jiejin disease, lymphoma, blood disease.
Sixth, pseudo-AIDS syndrome: AIDS phobia, British homosexuals saw some neurological symptoms similar to the early symptoms of AIDS.
Seven, central nervous system diseases: brain damage can be caused by AIDS or other causes, need to be identified.
