Tuberculosis is an insidious disease that affects not only adults, but also children. The disease is caused by the activity of mycobacteria (Koch's rods) in the human body. In the treatment of pathology, multicomponent chemotherapy is used, which can last up to six months or more. In 50% of cases without treatment, the disease ends in death. What is Koch's tubercle bacillus, how does it enter the human body and how to prevent the development of the disease - we will deal with these issues in our article.
The concept of mycobacteria
Tuberculosis is an infectious disease caused by mycobacteria of the Mycobacterium tuberculosis group (MBT). This type of bacteria is often called Koch's rods - after the name of the German scientist Robert Koch. Science knows about 74 species of mycobacteria that live in soil, water, in the body of animals and humans. I must say that the strains of tuberculosis caused by different types of mycobacteria differ from each other.
Tuberculus bacillus has a special protective shell that helps bacteria survive in the environment. MTB has a straight or slightly curved shape,immobile, does not form capsules or spores, reproduces very slowly by elementary division into two cells, while the division cycle is 14–18 hours. As a rule, reproduction occurs in two ways - by budding, less often by branching.
The size of mycobacteria is negligible: diameter ranges from 0.2–0.6 microns, length - 1–10 microns. Tuberculosis bacillus is classified as a fungus, because their similarity is manifested in the same oxygen consumption. MTB colonies slowly (within 34-55 days) grow on a dense nutrient medium, have a rough surface, are weakly pigmented - pink-orange or milky in color.
Structure of the MTB cell
Bacterial cells of tubercle bacillus consist of the following elements:
- cell wall - formed by several layers that protect the mycobacterium from mechanical and chemical effects; ensures the constancy of the size and shape of the cell (by the way, the protective shell includes waxy, fatty substances);
- bacterial cytoplasm with granular inclusions;
- cytoplasmic membrane;
- nuclear substance containing one circular DNA.
MBT is very resistant to environmental influences and retains its viability for a long time. How long does a tubercle bacillus live? Mycobacterium can survive: up to 7 years in a damp and dark place at a temperature of 23 ° C; up to 12 months in a dark and dry place; up to 6 months in soil; up to 5 months in water; up to 3 months in books; up to 2 months in street dust; up to 2 weeks in raw milk; up to a year in oil andcheese. Mycobacterium tuberculosis is not afraid of decay processes and can exist for several months in bodies buried in the ground. However, the direct rays of the sun destroy the MBT within an hour and a half, ultraviolet rays - in a few minutes. Chlorine-containing disinfectants cope with the bacillus in 5 hours. Mycobacteria are also sensitive to hydrogen peroxide. Tuberculosis bacilli die when heated: within 20 minutes at 60 °C and within 5 minutes at 70 °C.
MBT can cause disease after two to three years of asymptomatic existence and for a long time induce anti-tuberculosis immunity in the body.
What is tuberculosis?
As noted earlier, tuberculosis is an infectious disease caused by the activity of mycobacteria. Most of the disease is spread by airborne droplets from an infected person to a he althy person through contact (coughing, sneezing, talking). Sometimes the infection can be food in nature (raw milk).
At risk are people who are constantly in premises with unsuitable sanitary conditions - prisons, homes for the homeless. This also includes patients with a weakened immune system (HIV-infected, cancer patients). Patients with diabetes; babies; elderly; family members of those suffering from tuberculosis; smokers; people with poor nutrition - it is these categories of citizens that are most often attacked by a tubercle bacillus. The method of nutrition involves the mandatory consumption of vitamins and trace elements that help restore reduced immune functions.
Tuberculosis is caused byindividual characteristics of the organism, and is also directly related to the psychological state of a person. According to the age limit, a group of people aged 18–26 dominates.
The peculiarity of this pathology is that the tubercle bacillus quickly acquires resistance to drugs, so the treatment method involves the use of several drugs at the same time.
According to WHO statistics, about a third of the world's population is infected with Koch's bacillus, however, a he althy body does not allow MBT to multiply. Pathology occurs in the human body only under favorable conditions for this - reduced immunity. About three million people die every year from complications caused by tuberculosis worldwide. World TB Day is held on March 24.
Transmission of tuberculosis
There are four main ways in which the tubercle bacillus is spread:
- airborne, when mycobacteria enter the air with droplets when the patient coughs, sneezes;
- alimentary - infection occurs through the gastrointestinal tract;
- contact - infection occurs through the conjunctiva of the eye (infection through the skin is quite rare);
- intrauterine - infection through the affected placenta during childbirth from mother to child.
In a he althy body, the respiratory system is protected from the penetration of mycobacteria by mucus, which is secreted by special cells. However, with inflammation of the respiratory system, as well as under the influence oftoxins "protection" does not work. The probability of infection by the alimentary route depends on the condition of the intestinal wall, its absorption capacity.
Since the tubercle bacillus is outside the cell and multiplies slowly, the tissues retain their he althy structure for some time, however, mycobacteria after some time with the lymph flow enter the lymph nodes and spread throughout the body. The most favorable for mycobacteria are organs with a developed microcirculatory bed (lungs, cortical layer of the kidneys, fallopian tubes). As soon as the MBT penetrate the cell, they begin to damage its structure and divide.
Anatomy of pathology
In the infected organs, a “cold” inflammation occurs, which leads to the formation of many granulomas - tubercles prone to decay. The reaction of the body manifests itself a few weeks after infection. Cellular immunity is formed after two months. The next phase of the development of the pathological process is characterized by a slow growth of the MBT, the inflammatory reaction disappears, however, the pathogen from the focus of inflammation is not completely eliminated.
Tuberculosis bacillus persists in the body for a long time, and a person can be a carrier of MBT all his life. When immunity is weakened, the remaining MBT population will begin to actively divide, causing the consistent development of tuberculosis. The risk of developing pathology in a newly infected person is 10% during the first two years after infection. Over time, the likelihood ofdisease will decline.
With a weakened immune system, the body is unable to resist the multiplication of bacterial cells, which occurs exponentially. For the vital activity of MTB, a special favorable environment is formed, in which isolated granulomas merge into a common volume, while it is said that the primary infection passes into the phase of clinical tuberculosis. The inflammatory process spreads further throughout the functional system.
Forms and types of tuberculosis
After infection, the pathology acquires a latent form, i.e., most often it is asymptomatic. Only one out of ten cases goes into the active phase. The tuberculosis bacillus mostly affects the lungs, but it can also affect other body systems.
There are two forms of tuberculosis:
- open,
- closed.
With an open form, the presence of a tubercle bacillus is easily detected in the sputum or other secretions of the patient (urine, feces). Failure to comply with hygiene precautions in this form can lead to infection of others. With the closed form, mycobacteria are not detected, and patients do not pose a threat to others.
Depending on which functional system is exposed to tubercle bacillus, the pathology is classified into:
- pulmonary tuberculosis,
- extrapulmonary TB.
Depending on how much the pathology has spread in the body, they distinguish:
- latent TB,
- disseminatedtuberculosis,
- focal tuberculosis,
- caseating pneumonia,
- tuberculoma,
- fibrous-cavernous tuberculosis,
- cirrhotic tuberculosis,
- tuberculosis of the pleura, larynx or trachea is quite rare.
Extrapulmonary tuberculosis affects any other organ, according to which the pathology is classified into:
- tuberculosis of the central nervous system and membranes of the brain - the disease affects the spinal cord and hard membranes of the brain;
- organs of the digestive system, in which, as a rule, the small and caecum are affected;
- tuberculosis of the genitourinary organs affects the kidneys, urinary tract, genital organs;
- bone structures;
- skin tuberculosis;
- eye tuberculosis.
Clinical manifestations of pathology. Tuberculosis of the CNS
As mentioned earlier, due to the fact that the tubercle bacillus divides extremely slowly, it is impossible to detect it at the earliest possible time. Therefore, the pathology may not manifest itself for a long time, and later be discovered by chance during fluorography or tuberculin tests. In addition, specific signs of the disease, in fact, do not exist. The fact that intoxication occurs in the body may be indicated by pallor of the skin, chronic fatigue or lethargy, apathy, a slight increase in body temperature (about 37 ° C), excessive sweating, weight loss, swollen lymph nodes.
Laboratory analysis of the blood of tuberculosis patients revealsiron deficiency, a decrease in the number of leukocytes. Later, when the disease enters a more active phase, the above symptoms will be joined by clear signs of the pathology of the affected organ.
If mycobacterium affects the central nervous system, then the patient has, in addition to high temperature, sleep disturbance, aggression, severe headaches, vomiting. At the end of the second week from the beginning of the manifestation of the first signs, changes occur in the structures of the meninges, which are characterized by tension in the neck muscles and the inability to press the chin to the chest, to stretch the legs as much as possible. Patients with diabetes mellitus or carriers of the immunodeficiency virus are at risk. There are frequent cases of the occurrence of mental disorders against the background of this pathology, as well as impaired consciousness, sensitivity, movement of the eyeballs.
Unlike the disease in an adult, the tuberculosis bacillus in children causes a different course of the disease, more rapid and severe, sometimes leading to death. This is justified primarily by the underdeveloped immune system of the child. Subject to this pathology most often children who are in unsanitary conditions, malnourished, constantly overtired. Tuberculosis bacillus in children causes specific symptoms in the body, so the attention of parents should be attracted by vomiting, fatigue of the child, reduced attention, loss of appetite, weight loss, fever.
Tuberculosis of other functional systems
In addition to the lungs and elements of the central nervous system, pathology can attack other organs in the bodyhuman, such as the respiratory system. So, tuberculous pleurisy is a lesion of the pleura, the membrane that covers the lungs. This pathology can be an independent disease, or occur as a result of a complicated course of tuberculosis of the pulmonary system. Another complication of pulmonary tuberculosis can be tuberculosis of the upper respiratory tract, when the pharynx and larynx are involved in the inflammatory process. Symptoms of such a disease, in addition to the above, are hoarseness of the voice or difficulty in swallowing.
Loss of Koch's stick of lymph nodes is called tuberculous lymphadenitis. Most often, supraclavicular or cervical lymph nodes are attacked, which are enlarged but painless.
MTB can also affect the organs of the genitourinary system. The disease is manifested by sharp pains in the lower back or back, high body temperature. When urinating, bloody discharge is possible. Pathology occurs in equal proportion in both women and men.
Tuberculosis of bone tissue is characterized by frequent fractures, severe pain in the affected area, and the inability to move normally. Advanced forms of this pathology often lead to death.
Diagnosis and treatment
In the diagnosis of active tuberculosis, the most popular methods are microscopic examination of sputum and fluoroscopy. Smear analysis, however, cannot be called a reliable and unambiguous method, since in the early stages of pathology, as well as in the case of a disease in children, the study gives a negative result.
X-ray diagnostic methods are effective mainly in the late stages of the disease. In addition to these diagnostic methods, a skin tuberculin test is often used, which is commonly called the Mantoux reaction.
The main task when choosing a treatment regimen for a patient is to study the drug resistance of the pathogen, i.e., the sensitivity of a laboratory-grown mycobacterium culture to drugs.
Today, the main method of treating tuberculosis is anti-tuberculosis chemotherapy, which is a multicomponent one. There are three-component, four-component and five-component treatment regimens.
The three-component scheme involves the use of three main drugs - Streptomycin, Isoniazid and para-aminosalicylic acid (PAS). This scheme is classical, however, today it is rarely used due to the high toxicity of PAS. In the four-component method, "Rifampicin" ("Rifabutin"), "Isoniazid", "Pyrazinamide", "Ethambutol" are used. Many medical centers use an even more advanced technique - a five-component regimen, which, in addition to the above four drugs, uses Ciprofloxacin.
It must be said that tuberculosis is an insidious disease, to the development of which in the human body it is the tubercle bacillus. Treatment should be immediate and correct, because in the absence of therapy, death from pathology ends in 50% of cases. Death occurs within a few years from the onset of the active phase of the disease. The remaining 50% of cases lead to a chronic form of the disease. Moreover, a patient with severe chronic tuberculosis is dangerous to others, as it releases mycobacteria into the environment.
Prevention
Prophylactic measures against tuberculosis today include, perhaps, the BCG vaccine, which effectively protects against one of the most dangerous forms of tuberculosis - tuberculous meningitis. According to the National Immunization Schedule, a child is vaccinated at the maternity hospital during the first 3-7 days of life. Further, at the age of 7 and 14, revaccination is carried out under the condition of a negative Mantoux reaction and the absence of contraindications.
The BCG vaccine (Bacillus Calmette-Gerin) shows excellent results, but mandatory vaccination against tuberculosis is not accepted in all countries of the world, it all depends on the level of tuberculosis in the region. A few months after vaccination, a skin reaction appears at the injection site - a slight induration.
Vaccination is contraindicated for a child if:
- a newborn is diagnosed with immunodeficiency, and also when there are persons suffering from this pathology in the baby's family;
- siblings of the newborn had complications after such a vaccination;
- the child has congenital pathologies of the central nervous system.
Vaccination is postponed if:
- the baby is not full term,
- he hasany infectious disease detected,
- mother and baby have different Rh factor.
It is important to remember that tuberculosis bacillus causes an intractable disease. The nutrition of a sick person during therapy should be he althy and correct. Excess consumption of fatty foods should be avoided. The assimilation of such nutrition in patients with tuberculosis is difficult. This is due to the anatomical structure of the MTB cell - its shell contains a lot of fat. A person with a pathology needs food rich in proteins, carbohydrates, vitamins and trace elements.
To minimize the likelihood of primary infection at home, you must follow the rules of hygiene, spend more time outdoors, hang woolen and cotton products in the sun.
