AIDS, Acquired Immunodeficiency Syndrome (or Acquired Immunodeficiency Syndrome, AIDS, pronounced as AIDS), is an infection by the retrovirus of Human Immunodeficiency Virus (HIV), which gradually becomes the target of many opportunistic diseases due to the disruption of the immune system. It is a syndrome, not just a disease, that contributes to a variety of clinical symptoms. At present, AIDS has spread to all provinces, autonomous regions and municipalities directly under the central government in mainland China, and the situation is very serious.
I. Epidemiology
1. Epidemiological overview: WHO reported that in 2010, there were 34 million living HIV carriers and AIDS patients worldwide, with 2.7 million new infections and 1.8 million deaths in the year. More than 7,000 people are newly infected every day, and the epidemic is present in all regions of the world, but more than 97% are in middle and low-income countries, especially in Africa. Experts estimate that the worst hit areas of the global epidemic may move from Africa to Asia. China’s CDC estimates that by the end of 2011, about 780,000 people were living with HIV and AIDS in China, with 3,181 new infections in Beijing from the beginning of the year until October 2015, and a total of 13,106 people living with HIV in the city. The epidemic has covered all provinces, autonomous regions and municipalities directly under the central government, and China is now facing the peak of HIV disease morbidity and mortality, and has begun to spread from high-risk groups such as drug addicts and clandestine prostitutes to the general population.
2, the source of infection: HIV-infected people and AIDS patients are the only source of infection of the disease.
3.Transmission route: HIV mainly exists in the blood, semen, vaginal secretions and breast milk of infected and sick people. ①Sex: unprotected sex with an infected partner, including homosexual, heterosexual and bisexual sexual contact. ②Intravenous drug use: Sharing unsterile injection tools used by an infected person with others is a very important route of HIV transmission. ③Mother-to-child transmission: During pregnancy, delivery and breastfeeding, HIV-infected mothers may transmit to their fetuses and infants. ④Blood and blood products (including artificial insemination, skin grafts and organ transplants). Handshakes, hugs, courtesy kisses, eating and drinking together, sharing toilets and bathrooms, sharing offices, public transportation, recreational facilities and other daily life contacts will not transmit HIV.
4.Susceptible people: The population is generally susceptible. High-risk groups include: male homosexuals, intravenous drug users, frequent sexual contacts with HIV carriers, frequent transfusions of blood and blood products, and babies born to HIV-infected mothers.
II. Pathogenesis
(A) The process of virus infection
1. primary infection HIV needs to enter cells with the help of receptors on the surface of susceptible cells, including the first and second receptors. hiv enters the body and reaches local lymph nodes within 24-48 hours, and the viral component can be detected in peripheral blood in about 5 days. Subsequently, viremia is produced, leading to acute infection.2. HIV infection process in human cells adsorption and penetration: After HIV-1 infects human body, it selectively adsorbs on CD4 receptors of target cells and enters host cells with the help of co-receptors. After cyclization and integration, transcription and translation, assembly, maturation and outgrowth, forming mature viral particles.3. Three clinical transitions after HIV infection Because the body’s immune system cannot completely clear the virus, forming a chronic infection, it can be clinically manifested as three transitions: typical progressives, rapid progressives and long-term non-progressors.
(B) Immunopathology
1, CD 4+ T lymphocytes decreased after HIV infection, the number of CD4+ T lymphocytes in the body is constantly decreasing, divided into three stages: ① acute infection: CD4+ T lymphocytes decreased rapidly in the short term. lymphocyte count continues to decrease slowly, mostly between 800 and 350/mm3, and this period lasts from a few months to ten years, with an average duration of about 8 years; ③ symptomatic period: CD4+ T lymphocytes decrease more rapidly again, mostly below 350/mm3, and some advanced patients drop to below 200/mm3 and decrease rapidly.
2, CD4+ T lymphocyte dysfunction.
3, abnormal immune activation.
4, immune reconstitution III, clinical manifestations of HIV infection in China is divided into the acute phase, asymptomatic phase and AIDS phase.
(A) Acute phase
Usually occurs about 2-4 weeks after the initial HIV infection. The main clinical manifestations are fever, sore throat, night sweats, nausea, vomiting, diarrhea, skin rash, arthralgia, swollen lymph nodes and neurological symptoms. Most patients have mild clinical symptoms that persist for 1-3 weeks and then resolve. HIV-RNA and P24 antigen can be detected in the blood during this period, while HIV antibodies appear only a few weeks after infection. CD4+ T lymphocyte count decreases transiently, and CD4/CD8 ratio may be inverted.
(ii) Asymptomatic phase
This phase can be entered from the acute phase or directly without obvious acute phase symptoms. The duration of this phase is usually 6-8 years. However, there are also those who progress rapidly and those who do not progress for a long time. The length of this period depends on the number and type of virus infected, the route of infection, the immune status of the body and other factors.
(C) AIDS stage
AIDS transmission route is the final stage after HIV infection. The patient’s CD4+ T-lymphocyte count decreases significantly, mostly <200/mm3, and the HIV plasma viral load increases significantly. The main clinical manifestations in this stage are HIV-related symptoms, various opportunistic infections and tumors.
HIV-related symptoms: mainly manifested as fever, night sweats and diarrhea lasting for more than one month; weight loss of 10% or more. Some patients show neuropsychiatric symptoms, such as memory loss, apathy, personality change, headache, epilepsy and dementia. Persistent generalized lymph node enlargement may also occur, characterized by: (i) enlargement of lymph nodes in two or more sites other than the groin; (ii) lymph node diameter ≥ 25px, no pressure pain, no adhesions; and (iii) duration of more than 3 months.
Common symptoms of HIV-associated opportunistic infections and tumors: fever, night sweats, enlarged lymph nodes, cough, sputum and blood, dysphagia, headache, vomiting, abdominal pain and diarrhea, gastrointestinal bleeding, dysphagia, decreased appetite, oral white spots and ulcers, various rashes, decreased vision, blindness, dementia, epilepsy, limb paralysis, emaciation, anemia, fecal incontinence, urinary retention, intestinal obstruction, etc.
Common opportunistic infections of the whistling system: Pneumocystis carinii pneumonia (PCP), tuberculosis, recurrent bacterial and fungal pneumonia.
Central nervous system: cryptococcal meningitis, tuberculous meningitis, toxoplasmosis encephalopathy, various viral meningoencephalitis.
Digestive system: Candida albicans esophagitis, and cytomegalovirus esophagitis, enteritis; Salmonella, dysentery bacillus, Campylobacter jejuni and Cryptosporidium enteritis.
Oral cavity: thrush, tongue hairy white spots, recurrent oral ulcers, gingivitis, etc.
Skin, lymph nodes: herpes zoster, infectious molluscum contagiosum, condyloma acuminata, fungal dermatitis, onychomycosis, lymph node tuberculosis
Eye: cytomegalovirus and toxoplasmosis retinitis.
Common tumors: cervical cancer, malignant lymphoma, Kaposi’s sarcoma, etc.
IV. Ancillary tests for HIV infection
①HIV antibody primary screening test (ELISA): high sensitivity, false positives may occur. For patients with positive primary screening, they should be confirmed by confirmatory test. ②HIV antibody confirmatory test (WB): WHO stipulates that as long as there are 2 env bands, it can be judged as positive. ③HIV-RNA: the sensitivity is 100%, but occasionally false positive may occur, but the false positive result is usually less than 2000 cp/ml, while the viral load during the acute infection period is usually high, averaging at 106 cp/ml. ④p24 antigen: it helps in early diagnosis, and the sensitivity and specificity are high. ⑤ Rapid detection test: whole blood or blood from capillaries can be collected, and the results are usually available in 15-30 minutes. However, the false-positive and false-negative rates are high, and it is not used as a routine test. It should be especially mentioned that patients in all stages, regardless of whether their disease is stable or not, need to monitor CD4+ T lymphocyte count and HIV-RNA in order to start antiviral therapy and antiviral medication adjustment in a timely manner.
V. Diagnostic criteria for HIV infection
①Epidemiological history: history of unsafe living, history of intravenous drug use, importation of blood or blood products not tested for anti-HIV antibodies, children born to HIV-positive persons or history of occupational exposure, etc. ②Clinical manifestations: different manifestations in each stage. ③Laboratory tests: HIV infection must be diagnosed with positive HIV antibodies confirmed by confirmatory tests, and HIV-RNA and P24 antigen testing can help in the diagnosis of HIV/AIDS, especially in shortening the antibody “window period” and helping in the early diagnosis of HIV infection in newborns.
Highly effective antiretroviral therapy is the most fundamental treatment for AIDS. It requires lifelong medication.
The goals of treatment: to maximize the inhibition of viral replication, to preserve and restore immune function, to reduce morbidity and mortality and the incidence of HIV-associated disease, to improve the quality of life of patients, and to reduce the transmission of AIDS.
Indications and timing for initiation of antiretroviral therapy.
①Indications and timing for initiation of antiretroviral therapy in adults and adolescents One of the following is recommended: patients in the AIDS phase; acute phase; CD4+ T lymphocytes <350 hiv-rna="">105 cp/ml in the asymptomatic phase; high risk of cardiovascular disease; comorbid active HBV/HCV infection; HIV-related kidney disease; pregnancy. Prior to initiation of HAART, the presence of severe opportunistic infections or acute exacerbations of previous chronic disease should be controlled and stabilized before treatment.
②Indications and timing for initiation of antiretroviral therapy in infants and children One of the following is recommended: infants <12 months of age; infants 12 to 35 months of age with CD4+ T lymphocyte ratio <20% or total <750/mm3; children over 36 months of age with CD4+ T lymphocyte ratio <15% or total <350/mm3.
Internationally available drugs: more than 30 drugs in six major classes. Nucleoside reverse transcriptase inhibitors (NRTIs), non-nucleoside reverse transcriptase inhibitors (NNRTIs), protease inhibitors (PIs), integrase inhibitors (raltegravir), fusion enzyme inhibitors (FIs), and CCR5 inhibitors (maraviroc). Adherence is important. Before antiviral therapy, there should be adequate communication with the patient so that they understand the need for treatment, the possible discomfort after treatment, the importance of compliance, the need for regular testing after taking the medication, and the need to contact the medical staff promptly in case of any discomfort. Support from their families or friends should also be obtained to improve patient compliance. CD4+ T lymphocytes, HIV-RNA and routine blood tests should be monitored during antiviral therapy to evaluate the efficacy and side effects.
VII. Disease prevention to prevent HIV infection
① Management of infectious sources: High-risk groups should be tested regularly for HIV antibodies, and infected persons found by medical and health departments should be reported in a timely manner, and HIV-related knowledge should be disseminated to infected persons to avoid transmission to others. The blood, body fluids and secretions of infected persons should be disinfected.
② Cut off the transmission route: avoid unsafe sexual behavior, prohibit sexual promiscuity, and outlaw prostitution. Strictly screen blood suppliers, strictly inspect blood products, and promote the use of disposable syringes. Injecting drugs, especially sharing needles to inject drugs, is strictly prohibited. Do not share dental tools or razors. Do not go to informal hospitals for examination and treatment.
③Protect susceptible people: advocate premarital and preconception medical checkups. HIV-positive pregnant women should be blocked from mother to child. This includes obstetric intervention (termination of pregnancy, cesarean section) + antiviral drugs + artificial feeding. Medical personnel strictly follow medical procedures to avoid occupational exposure.
VIII. Early identification of AIDS in symptomatology
(1) Persistent irregular fever of unknown cause above 38°C for >1 month.
(2) Chronic diarrhea more than 3 times/day for >1 month.
(3) Weight loss of more than 10% within 6 months
(4) Herpes appearing on the skin one after another, with an increasing tendency of herpes, with significant pain, and no improvement after several months of treatment. In addition, inflammation and ulceration of the mucous membrane in the mouth and throat. Or recurrent oral Candida albicans infections.
(5) Recurrent herpes simplex virus infection or herpes zoster virus infection.
(6) Pneumocystis carinii pneumonia (PCP).
(7) Recurrent bacterial pneumonia; prolonged cough that is difficult to stop, with blood in the sputum coughed up, accompanied by symptoms of chest pain
(8) Active tuberculosis or non-tuberculous mycobacteriosis.
(9) Deep fungal infection.
(10) Occupational lesions of the central nervous system.
(11) Dementia in middle-aged and young adults.
(12) active cytomegalovirus infection
(13) Toxoplasma gondii encephalopathy.
(14) Penicillium infection.
(15) Recurrent sepsis.
(16) Kaposi’s sarcoma, lymphoma of the skin mucosa or internal organs.
(17) Symptoms of lymphomegaly for more than six months in a row, and little effect on common treatment.