HIV infection
The content of the article:
- Causes and risk factors
- Disease stages
- Symptoms
- Diagnostics
- Treatment
- Possible complications and consequences
- Forecast
- Prevention
HIV infection is a slowly progressive disease with a contact mechanism of transmission caused by the Human Immunodeficiency Virus Infection (HIV-infection), belonging to the family of retroviruses, a genus of lentiviruses (so-called slow viruses).
Symptoms of Acute HIV Infection
It is characterized by damage to the immune system with the subsequent development of acquired immune deficiency syndrome (AIDS), clinically manifested by the occurrence of secondary infectious diseases (opportunistic infections), autoimmune processes, and malignant neoplasms.
The virus was first isolated in 1983 in Paris by a group of scientists led by Luc Montagnier from a biopsy specimen of the lymph node of an AIDS patient. In parallel, a similar virus was discovered by Professor Robert Gallo in the United States in the blood of an infected person. In 1987, the World Health Organization adopted a single name for the causative agents of AIDS - Human Immunodeficiency Virus.
The structure of HIV has been reliably established using electron microscopy. The viral particle itself forms the nucleus of the virion, surrounded by a protective protein envelope built from host proteins interspersed with viral proteins.
Under natural conditions, the virus remains active in biological fluids for several days, in frozen blood plasma - up to several years.
As of December 2016, in the Russian Federation alone, there were about 1.5 million registered HIV-infected, in the world this figure for the entire time (from the beginning of AIDS diagnostics to the present day) exceeds 60 million, at the present time more than 60 million live on the planet with a confirmed diagnosis. 35 million people. Two thirds of all HIV-positive people live in Africa, in the regions of sub-Saharan Africa.
Causes and risk factors
The source of HIV infection is a person who is a carrier of the virus, even during the incubation period in the absence of clinical manifestations of the disease.
There are 2 types of human immunodeficiency viruses: HIV-1 and HIV-2. These varieties differ in antigenic composition and structure, certain clinical and epidemiological features. Type HIV-1 predominates.
HIV is distributed in all body fluids; its highest concentration is observed in blood, semen and precum, vaginal secretions and cervical mucus, breast milk. The virus is also detected in saliva, urine, sweat, cerebrospinal and lacrimal fluids, but its concentration in these environments is much lower.
HIV infection is transmitted from person to person by droplets, parenteral, antenatal routes
There are 3 main ways HIV is transmitted:
- contact, carried out during homo- or heterosexual sexual intercourse (more than 85% of all cases of infection);
- parenteral, arising from transfusion of infected blood and its components;
- from mother to child [vertical, antenatal transmission of the virus (involving intrauterine infection of the fetus during pregnancy) (observed in 30-50% of cases in HIV-positive mothers), intrapartum (at the time of passing through the birth canal), postnatal (in the postpartum period when breastfeeding)].
Information on the possibility of HIV transmission by airborne droplets, fecal-oral, transmissible methods has no evidence base.
Risk factors:
- the presence of sexually transmitted diseases [the risk of infection by contact is several times higher (according to some sources, several dozen) times], such as syphilis, herpes, chlamydia, gonorrhea and bacterial vaginosis;
- promiscuous sex;
- unprotected sex;
- injecting drugs (sharing syringes, needles);
- blood transfusion and non-sterile manipulations, implying a violation of the integrity of the skin;
- asocial lifestyle (vagrancy, street prostitution, etc.);
- accidental injury from an infected needle or contact with infected blood (there is a risk from medical workers, hotel personnel, air and sea lines of international transport).
HIV infection is not transmitted:
- when shaking hands;
- when using cutlery and bedding;
- when sharing furniture or production equipment;
- when using the pool, shower, sanitary ware;
- with insect bites.
Disease stages
Clinical classification of HIV infection according to V. I. Pokrovsky (adopted in the Russian Federation):
- stage I - incubation (from several weeks to months or years);
- stage II - primary manifestations (can last up to 10 years): IIA - acute febrile phase; IIB - asymptomatic phase; IIB - persistent generalized lymphadenopathy;
- stage III - secondary diseases (pre-AIDS) (IIIA, IIIB, IIIB);
- stage IV - terminal (AIDS).
World Health Organization classification:
- stage I - asymptomatic;
- stage II - early, or mild;
- stage III - intermediate;
- stage IV - terminal.
In the United States, the CDC classification has been developed and widely used, which evaluates both clinical and laboratory parameters (the number of CD4 + T-lymphocytes in 1 μl of blood).
Symptoms
The target of viruses are immune cells carrying the CD4 + marker on their surface (T-lymphocytes, macrophages, Langerhans cells, follicular dendritic cells, alveolar macrophages, epithelial cells of the large intestine and kidneys, cervical cells, oligodendroglia, astrocytes); the virus also infects CD8 + lymphocytes.
Penetrating into the cells of the immune system, the virus embeds its DNA into the DNA of the host cell, reconfiguring its work for the production of structural elements of HIV, from which, under the influence of a specialized enzyme, new full-fledged viruses are assembled and continue to colonize the host's organism.
The HIV virus embeds its DNA into the DNA of a human cell, changing how it works
The defeat of the cells carrying CD4 + receptors leads to an immune imbalance, as a result of which control over the penetration of all kinds of pathogenic elements (bacteria, fungi, viruses) into the organism of the virus carrier and the development of malignant neoplasms is lost.
In addition to the aggressive effect on the cells of the immune system, HIV has a destructive effect on the cells of other organs and systems (hematopoietic, nervous, cardiovascular, endocrine, etc.), which provokes the development of multiple organ failure with a wide variety of symptoms and the steady progression of HIV infection …
In the first weeks or months after infection, there are no symptoms of the disease. For the subsequent acute febrile phase, lasting 1–2 months, the following manifestations are characteristic:
- increased body temperature;
- intoxication phenomena (headache, muscle and joint pain, severe weakness, drowsiness);
- inflammation of the tonsils (tonsillitis);
- swollen lymph nodes;
- bark or rubella-like skin rash;
- ulcerative defects and erosion of the mucous membrane of the pharynx, less often - of the oral cavity;
- cough.
Inflammation of the lymph nodes in the neck with HIV infection
The acute phase is replaced by an asymptomatic one, which can last for several years, more often its duration is approximately 6 months. Despite the absence of clinically significant manifestations, the disease is steadily progressing, the number of HIV virions in the biological environment of the body is growing.
Stage IIB (persistent generalized lymphadenopathy) is characterized by an isolated increase in the size of the lymph nodes (more often than others, the posterior cervical, supraclavicular, axillary and ulnar nodes are involved in the pathological process), which is not accompanied by inflammation in the nearby anatomical areas. Swollen lymph nodes persist for months or years.
The following symptoms are characteristic of pre-AIDS:
- fever - body temperature 38 ºС, torrential sweat, severe general weakness, deterioration in the tolerance of habitual physical activity;
- weight loss;
- lesions of the skin and mucous membranes (candidiasis, leukoplakia, condylomas);
- persistent diarrhea of unknown etiology;
- various dyspeptic disorders.
At this stage, a secondary opportunistic infection actively joins, provoking the development of a number of diseases (rhinitis, pharyngitis, sinusitis, tracheitis, bronchitis, pneumonia, meningitis, infections of soft tissues, bones and joints, recurrent herpes, ulcerative necrotic diseases of the oral cavity, fungal nail infections, malignant neoplasms, etc.).
Symptoms of the terminal stage of HIV infection (AIDS itself) are represented by severe exhaustion, damage to the central and peripheral nervous system, endocrine disorders, severe astheno-neurotic manifestations and powerful intoxication. The patient is bedridden, irreversible changes in the cognitive sphere develop.
Diseases characteristic of the terminal stage: tuberculosis, salmonellosis, cytomegalovirus infection, candidiasis, herpetic esophagitis, cryptosporidiosis, toxoplasmosis, meningoencephalitis, progressive multifocal leukoencephalopathy, histoplasmosis, cryptococcal tumors, cancer
Diagnostics
Laboratory diagnostic methods have the greatest informative value in detecting HIV infection. The entire arsenal of diagnostic tests can be divided into several groups:
- tests to detect antibodies to HIV [enzyme-linked immunosorbent assay (ELISA), immunochemical analysis (ICA), immune blotting];
- tests to detect HIV antigens [polymerase chain reaction (PCR)];
- tests to detect and monitor the amount of viral nucleic acids.
The standard procedure in the Russian Federation is currently the detection of antibodies to HIV (first level diagnosis). In case of a positive ELISA reaction, ICA, a confirmatory test is performed - immune blotting - in order to determine the specificity of the identified antibodies (the second level of diagnosis).
The enzyme-linked immunosorbent assay (ELISA) detects antibodies to HIV in the blood
The results of the immune blot are defined as "positive", "negative", "indeterminate" according to the criteria set forth in regulatory documents.
Sometimes the phenomenon of a seronegative window is noted, when, despite the high concentration of the virus in the body, the test results are negative (antibodies to HIV are formed within 28 days after infection and may be absent during the analysis at an early stage). To eliminate diagnostic inaccuracies, it is recommended to repeat ELISA (IHA) 6 months after a possible infection.
Nowadays, methods of express diagnostics are widely used, allowing to obtain a result within 10-15 minutes.
Treatment
A turning point in the treatment of the disease was 1996, when antiretroviral drugs were introduced into clinical practice. If until that time HIV infection was considered a fatal disease, now we can talk about it as a controlled chronic process.
Adequate pharmacotherapy can slow down or stop the progression of the disease, however, there are currently no means to destroy viruses.
Therapy is carried out in several directions:
- antiretroviral therapy (nucleoside analogs that inhibit HIV reverse transcriptase, non-nucleoside HIV transcriptase inhibitors, HIV protease inhibitors);
- treatment of secondary diseases (parasitic, bacterial, viral, protozoal or fungal infections, malignant neoplasms);
- pathogenetic therapy of concomitant syndromes.
Therapy for HIV infection begins as early as possible from the moment of confirmation of the diagnosis, and is implemented for life.
Antiretroviral therapy for HIV can manage disease
Possible complications and consequences
The main complications are the progression of the disease and the development of AIDS, complicated by various pathological conditions.
Forecast
The average life expectancy of the overwhelming majority of HIV-infected patients who do not receive treatment is 3-11 years, with adequate therapy it is comparable to the average life expectancy.
Prevention
HIV prevention measures:
- use of contraceptives;
- giving up unprotected sex with a casual partner;
- refusal to take drugs;
- regular HIV testing of people at risk;
- antiretroviral prophylaxis if a partner has HIV;
- implementation of measures for the transmission of HIV from mother to child during pregnancy, childbirth, in the postpartum period.
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Olesya Smolnyakova Therapy, clinical pharmacology and pharmacotherapy About the author
Education: higher, 2004 (GOU VPO "Kursk State Medical University"), specialty "General Medicine", qualification "Doctor". 2008-2012 - Postgraduate student of the Department of Clinical Pharmacology, KSMU, Candidate of Medical Sciences (2013, specialty "Pharmacology, Clinical Pharmacology"). 2014-2015 - professional retraining, specialty "Management in education", FSBEI HPE "KSU".
The information is generalized and provided for informational purposes only. At the first sign of illness, see your doctor. Self-medication is hazardous to health!
