HIV infection is a disease caused by the human immunodeficiency virus, characterized by acquired immunodeficiency syndrome, contributing to the occurrence of secondary infections and malignant tumors due to the deep suppression of the protective property of the organism. HIV infection has a variety of options for the course. The disease can last only a few months or stretch to 20 years. The main way to diagnose HIV infection is to identify specific antiviral antibodies, as well as viral RNA. Currently, HIV patients are being treated with antiretroviral drugs that can reduce the reproduction of the virus.
HIV infection is a disease caused by the human immunodeficiency virus, characterized by acquired immunodeficiency syndrome, contributing to the occurrence of secondary infections and malignant tumors due to the deep suppression of the protective property of the organism. Today the world is experiencing a pandemic of HIV infection, the incidence of the population of the planet, especially in Eastern Europe, is steadily increasing.
Characteristics of the pathogen
Human immunodeficiency virus, DNA-containing, belongs to the genus Lentivirus of the family Retroviridae. There are two types: HIV-1 is the main causative agent of HIV infection, the cause of a pandemic, the development of AIDS. HIV-2 is a less common type, mainly found in West Africa. HIV is an unstable virus. It quickly dies outside the body of the carrier, is sensitive to the effects of temperature (reduces infectious properties at a temperature of 56 ° C, dies after 10 minutes when heated to 70-80 ° C). It is well preserved in the blood and its preparations prepared for transfusion. The antigenic structure of the virus is highly variable.
The reservoir and source of HIV infection is a person: suffering from AIDS and a carrier. There are no natural reservoirs of HIV-1, it is believed that wild chimpanzees are the natural host in nature. HIV-2 is transmitted by African monkeys. Susceptibility to HIV in other animal species is not marked. The virus is found in high concentrations in the blood, semen, secretions of the vaginal glands and menstrual flow. It can be isolated from human milk, saliva, lacrimal secretion and cerebrospinal fluid, but these biological fluids are less epidemiologically dangerous.
The likelihood of transmitting HIV infection increases when there are injuries to the skin and mucous membranes (trauma, abrasion, cervical erosion, stomatitis, paradontosis, and others). child) and artificial (mainly implemented with hemoperculated transmission mechanism: during transfusions, parenteral administration of substances, traumatic medical procedures).
The risk of HIV infection with a single contact with a carrier is low, regular sex with an infected person increases it significantly. Vertical transmission of infection from a sick mother to a child is possible both in the prenatal period (through defects of the placental barrier) and in childbirth, when the baby comes in contact with the mother’s blood. In rare cases, postnatal transmission with breast milk is fixed. The incidence among children in infected mothers reaches 25-30%.
Parenteral infection occurs when injecting with the help of needles contaminated with the blood of HIV-infected persons, with blood transfusions of infected blood, non-sterile medical manipulations (piercing, tattoos, medical and dental procedures, which are produced with the tools without proper treatment). Domestic HIV is not transmitted by contact. A person’s susceptibility to HIV infection is high. The development of AIDS in persons older than 35 years, as a rule, occurs in a shorter time from the moment of infection. In some cases, HIV immunity is noted, which is associated with specific immunoglobulins A present on mucosal genital organs.
Pathogenesis of HIV infection
Human immunodeficiency virus, when released into the blood, is introduced into macrophages, microglia and lymphocytes, which are important in the formation of the body’s immune responses. The virus destroys the ability of immune cells to recognize their antigens as foreign, populates the cell and proceeds to reproduction. After the virus has multiplied in the blood, the host cell dies and viruses invade healthy macrophages. The syndrome develops slowly (over the years), in waves.
At first, the body compensates for the massive death of immune cells, producing new ones, over time, the compensation becomes insufficient, the number of lymphocytes and macrophages in the blood decreases significantly, the immune system is destroyed, the body becomes defenseless both in relation to exogenous infections and to the bacteria that inhabit the organs and tissues normal (leading to the development of opportunistic infections). In addition, the mechanism of protection against the reproduction of defective blastocytes - malignant cells - is violated.
The virus colonization of immune cells often provokes various autoimmune conditions, in particular, neurological disorders resulting from autoimmune neurocyte lesions, which may develop even before the immunodeficiency clinic manifests itself.
In the clinical course of HIV infection, there are 5 stages: incubation, primary manifestations, latent, stage of secondary diseases and terminal. The stage of primary manifestations may be asymptomatic, in the form of a primary HIV infection, and also be combined with secondary diseases. The fourth stage, depending on the severity is divided into periods: 4A, 4B, 4B. The periods go through phases of progression and remission, which differ depending on the presence of antiretroviral therapy or its absence.
Symptoms of HIV Infection
Incubation Stage (1) - can be from 3 weeks to 3 months, in rare cases it is extended up to a year. At this time there is an active reproduction of the virus, but the immune response to it is not yet available. The incubation period of HIV ends with either an acute HIV infection clinic or the appearance of HIV antibodies in the blood. At this stage, the basis for the diagnosis of HIV infection is the detection of a virus (antigens or DNA particles) in the serum.
Stage of primary manifestations (2) characterized by the manifestation of the body's reaction to the active replication of the virus in the form of an acute infection clinic and an immune reaction (the production of specific antibodies). The second stage can be asymptomatic, the only sign of developing HIV infection will be a positive serological diagnosis for antibodies to the virus.
Clinical manifestations of the second stage occur according to the type of acute HIV infection. The onset is acute, noted in 50-90% of patients three months after the time of infection, often preceding the formation of HIV antibodies. An acute infection without secondary pathologies has a rather diverse course: fever, various polymorphic rashes on the skin and visible mucous membranes, polylimphadenitis, pharyngitis, lienal syndrome, diarrhea can occur.
In 10-15% of patients, acute HIV infection occurs with the addition of secondary diseases, which is associated with a decrease in immunity. These can be sore throats, pneumonia of various origins, fungal infections, herpes, etc.
Acute HIV infection usually lasts from several days to several months, on average 2-3 weeks, after which, in the overwhelming majority of cases, it passes into the latent stage.
Latent stage (3) characterized by a gradual increase in immunodeficiency. The death of immune cells at this stage is offset by their increased production. At this time, HIV can be diagnosed using serological tests (antibodies to HIV are present in the blood). A clinical sign may be an increase in several lymph nodes from different unrelated groups, excluding inguinal lymph nodes. At the same time, there are no other pathological changes in the enlarged lymph nodes (tenderness, changes in the surrounding tissues). The latent stage can last from 2-3 years, up to 20 and more. On average, it lasts 6-7 years.
Stage of secondary diseases (4) characterized by the occurrence of concomitant (opportunistic) infections of viral, bacterial, fungal, protozoal genesis, malignant formations against the background of pronounced immunodeficiency. Depending on the severity of secondary diseases, there are 3 periods of the course.
- 4A - the loss of body weight does not exceed 10%, infectious (bacterial, viral and fungal) lesions of integumentary tissues (skin and mucous membranes) are noted. Performance reduced.
- 4B - loss in weight of more than 10% of the total body mass, prolonged temperature reaction, prolonged diarrhea that has no organic cause can occur, pulmonary tuberculosis can join, infectious diseases recur and progress, localized Kaposi's sarcoma and hairy leukoplakia are detected.
- 4B - general cachexia is noted, secondary infections acquire generalized forms, esophageal candidiasis, respiratory tract infections, Pneumonia pneumonia, extrapulmonary tuberculosis, disseminated Kaposi's sarcoma, neurological disorders are noted.
Substeps of secondary diseases go through the phases of progression and remission, which differ depending on the presence or absence of antiretroviral therapy. In the terminal stage of HIV infection, the secondary diseases that have developed in the patient become irreversible, the treatment measures lose their effectiveness, the lethal outcome occurs after a few months.
The course of HIV infection is quite diverse, all stages are not always the case, some clinical signs may be absent. Depending on the individual clinical course, the duration of the disease may be several months or 15-20 years.
Features of the clinic of HIV infection in children
HIV in early childhood contributes to the delay of physical and psychomotor development. Recurrence of bacterial infections in children is noted more often than in adults, lymphoid pneumonitis, an increase in pulmonary lymph nodes, various encephalopathies, and anemia are common. A common cause of infant mortality in HIV infections is hemorrhagic syndrome, which is a consequence of severe thrombocytopenia.
The most frequent clinical manifestation of HIV infection in children is a delay in the pace of psychomotor and physical development. HIV infection received by children from mothers of the ante-and perinatal course is noticeably harder and progresses faster, unlike in children infected after one year.
Currently, the main diagnostic method for HIV infection is the detection of antibodies to the virus, produced mainly using the ELISA technique. In case of a positive result, blood serum is examined using an immune blot technique. This allows the identification of antibodies to specific HIV antigens, which is a sufficient criterion for the final diagnosis. Failure to detect a characteristic molecular weight by blotting antibodies, however, does not exclude HIV. During the incubation period, the immune response to the introduction of the virus has not yet been formed, and in the terminal stage, as a result of pronounced immunodeficiency, antibodies cease to be produced.
When HIV is suspected and there are no positive results from immune blotting, PCR is an effective method for detecting virus RNA particles. Diagnosed with serological and virological methods, HIV infection is an indication for the dynamic observation of the state of the immune status.
Therapy of HIV-infected individuals implies constant monitoring of the immune status of the body, prevention and treatment of emerging secondary infections, control over the development of tumors. Often, people living with HIV need psychological help and social adaptation. Currently, due to the significant spread and high social significance of the disease on a national and global scale, support and rehabilitation of patients is being carried out, access to social programs that provide patients with medical care, facilitating the course and improving the quality of life of patients, is expanding.
To date, the predominant etiotropic treatment is the prescription of drugs that reduce the reproductive ability of the virus. Antiretroviral drugs include:
- NRTIs (nucleoside transcriptase inhibitors) of various groups: zidovudine, stavudine, zalcitabine, didanosine, abacavir, combination drugs,
- NTII (nucleotide reverse transcriptase inhibitors): nevirapine, efavirenz,
- protease inhibitors: ritonavir, saquinavir, darunavir, nelfinavir and others,
- fusion inhibitors.
When deciding on the initiation of antiviral therapy, patients should remember that the use of drugs has been taking place for many years, almost for life. The success of therapy directly depends on strict adherence to the recommendations: timely, regular medication in the required dosages, adherence to the prescribed diet and strict adherence to the regimen.
Emerging opportunistic infections are treated in accordance with the rules effective against the pathogen that caused them (antibacterial, antifungal, antiviral agents). Immunostimulating therapy for HIV infection is not used, because it contributes to its progression, cytotoxic drugs prescribed for malignant tumors, inhibit immunity.
Treatment of HIV-infected people includes fortifying and supporting the body (vitamins and biologically active substances) and methods of physiotherapy for the prevention of secondary diseases. Patients suffering from drug addiction are recommended treatment in appropriate dispensaries. Due to significant psychological discomfort, many patients undergo a long-term psychological adaptation.
HIV infection is completely incurable, in many cases antiviral therapy gives little result. Today, on average, HIV-infected live 11-12 years, but careful therapy and modern medical preparations will significantly extend the life of patients. The main role in deterring developing AIDS is played by the patient’s psychological state and his efforts to comply with the prescribed regimen.
Currently, the World Health Organization is conducting general preventive measures to reduce the incidence of HIV infection in four main areas:
- sexual safety education, distribution of condoms, treatment of sexually transmitted diseases, promotion of a culture of sexual relationships,
- control over the manufacture of drugs from donor blood,
- Pregnancy of HIV-infected women, provision of their medical care and provision of chemoprophylaxis to them (women receive antiretroviral drugs in the last trimester of pregnancy and during childbirth, which are also prescribed to newborns in the first three months of life)
- organization of psychological and social assistance and support for HIV-infected citizens, counseling.
Nowadays, in world practice, special attention is paid to such epidemiologically important factors in relation to the incidence of HIV infection as drug addiction, promiscuous sex life. As a preventive measure in many countries, free distribution of disposable syringes, methadone replacement therapy is performed. As a measure to help reduce sexual illiteracy, sexual hygiene training courses are introduced into curricula.
Indications for consulting other specialists
Before conducting highly active antiretroviral therapy (HAART), all patients with HIV infection are examined by a therapist, neurologist, otorhinolaryngologist, and ophthalmologist to determine contraindications to the prescription of certain drugs. In addition, patients who have previously consumed or are constantly using psychoactive substances are referred for consultation to a narcologist. All patients with pulmonary pathology, especially with the ineffectiveness of antibiotic therapy, are examined by a phthisiopulmonologist. Consultations of other specialists are carried out according to indications, depending on the identified pathology (secondary or associated diseases), in order to determine the volume of additional examinations or to decide whether to transfer the patient to a highly specialized department or hospital.
Clinical diagnosis of HIV infection
Proper diagnosis of HIV infection is based on laboratory confirmation. Clinical diagnostics of secondary or concomitant diseases on the background of HIV infection is carried out: this makes it possible to determine the severity of the patient’s condition, the indications for hospitalization and to develop treatment tactics.
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Specific and non-specific laboratory diagnosis of HIV infection
In order to clarify the diagnosis of HIV infection, immunoblotting is carried out at AIDS prevention and control centers. To confirm the diagnosis of HIV infection using virological, molecular genetic (PCR) and serological methods (ELISA) and immunoblotting.
Antibodies to HIV are determined after 2 weeks from the moment of infection. When registering the first positive result using ELISA analysis duplicate. After receiving a second positive response, this serum is sent to a study at the Center for the Prevention and Control of AIDS, where immunoblotting is carried out. The results of immunoblotting are assessed as positive, doubtful or negative.
When antibodies to any two or three HIV envelope glycoproteins (gp41, gpl20 and gpl60) are detected in the patient's serum, the samples are simultaneously considered positive. In the absence of serum antibodies to all antigens, the samples are evaluated as negative. If antibodies to HIV glycoprotein or any of its proteins are detected in the blood, then the samples are considered doubtful, requiring repeated research.
Isolation and identification of HIV culture (virological method) is a reliable criterion for assessing infection. Due to the complexity of this study is used only in extremely difficult to diagnose cases.
Quantitative version of PCR allows to evaluate the replicative activity of the virus, to determine the "viral load". In the stage of primary manifestations, the "viral load" is usually several thousand copies per 1 ml of blood. At the stage of secondary diseases, the level of HIV reaches hundreds of thousands of copies per 1 ml of serum and a million copies of the virus in AIDS.
Persistent high concentrations of HIV at an early stage of the disease are an unfavorable prognostic sign indicating that the virus is extremely aggressive.
The primary diagnosis of HIV infection is a responsible procedure that requires careful analysis of the data, because making an incorrect diagnosis can have serious consequences for the patient (depressive reaction, suicidal attempt, AIDS-phobia).
Laboratory confirmation of the diagnosis is required. Most commonly used methods for the detection of antibodies (first in ELISA, then in immunoblotting). Upon receipt of a dubious result when conducting immunoblotting, the patient needs follow-up and re-examination.
Example of a diagnosis wording
When making a diagnosis, the nosological unit of the disease is indicated - HIV infection according to ICD-10. then the stage of HIV infection, the phase and secondary diseases. If, against the background of HIV infection, at least one of the secondary diseases has a degree of manifestation that meets the criteria for acquired immunodeficiency syndrome, then AIDS is indicated after the disease phase.
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Z21. HIV infection, stage III (subclinical).
Q20.4. HIV disease with manifestations of candidiasis.
HIV infection, stage IVA, remission phase. Oropharyngeal candidiasis (in history).
B20.6. HIV disease. with manifestations of pneumonia caused by Pneumocystis carinii.
HIV infection, stage IVB, progression phase (AIDS). Pneumocystis pneumonia, candidiasis of the oral cavity and esophagus.
Q20.2. HIV disease with manifestations of cytomegalovirus disease.
HIV infection, stage IVB, remission phase (AIDS). Manifest cytomegalovirus infection with a lesion of the retina (in history).
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HIV screening stage
An enzyme-linked immunosorbent assay (ELISA) is used during the screening to determine total antibodies to HIV-1 and HIV-2. Shows accurate results no earlier than 3-6 months after infection, although there are exceptions: it can detect antibodies to HIV 3-5 weeks after dangerous contact.
The fourth generation test systems are the most accurate. In addition to antibodies to the virus, they are also able to detect an antigen to HIV (p-24-capsid), which makes it possible to detect the virus even in the "window period", before the appearance of antibodies.
The high cost of such test systems in many countries makes it necessary to use systems of the third and even second generation, which determine only the presence of antibodies.
Such systems give false positive results under the following conditions:
Infection during pregnancy,
Autoimmune diseases: psoriasis, rheumatism, systemic lupus erythematosus,
With a positive result of enzyme immunoassay, go to the next stage of diagnosis.
Expert stage - immunoblot
At this stage, antibodies to individual proteins of the human immunodeficiency virus are determined.
Stages of the expert stage:
The destruction of the virus into individual antigens using electrophoresis.
Transfer of antigens using the blot method on special strips with HIV-specific pre-applied proteins.
Fixation of the reaction that occurs if there are antibodies to antigens in the patient’s blood.
There is a small risk of error - a false negative result. It is possible if the study occurs in the terminal stage of the disease or in the "window period".
In combination with other tests using the method of PCR (polymerase chain reaction). It is characterized by an increased sensitivity to the virus, which can lead to a large proportion of false-positive results.