Tuberculosis is an insidious disease that affects not only adults but also children. The activity is caused by the activity of mycobacteria (Koch's bacillus) 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 of absence of treatment, the disease is fatal. What is Koch's tubercle bacillus, how it enters 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 Mycobacterium tuberculosis (MBT) mycobacteria. This type of bacteria is often called Koch sticks - by the name of the German scientist Robert Koch. Science knows about 74 species of mycobacteria that live in soil, water, in animals and humans. I must say that the strains of tuberculosis caused by various types of mycobacteria differ from each other.
Tuberculosis bacillus has a special protective shell that helps bacteria survive in environmental conditions. MTB has a straight or slightly curved shape, motionless, does not form capsules or spores, and very slowly multiplies 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: the diameter varies between 0.2–0.6 μm, the length is 1–10 μm. Tubercle bacillus is classified as a mushroom, because their similarity is manifested in the same oxygen consumption. MTB colonies grow slowly (within 34–55 days) on a dense nutrient medium, have a rough surface, weakly pigmented - pink-orange or milky.
MTB cell structure
Bacterial cells of tubercle bacillus consist of the following elements:
- cell wall - formed by several layers that protect mycobacteria from mechanical and chemical effects; provides constancy of the size and shape of the cell (by the way, the composition of the protective membrane includes waxy, fatty substances);
- bacterial cytoplasm with granular inclusions;
- cytoplasmic membrane;
- nuclear substance containing one circular DNA.
The Office is highly resistant to environmental influences and remains viable for a long time. How long does tubercle bacillus live? Mycobacteria can last: up to 7 years in a humid and dark place at a temperature of 23 ° C; up to 12 months in a dark and dry place; up to 6 months in the 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 butter and cheese. Mycobacterium tuberculosis is not afraid of decay processes and can exist for several months in bodies buried in the ground. However, direct rays of the sun destroy the office within an hour and a half, ultraviolet rays - in a few minutes. Chlorine-containing disinfectors cope with the bacillus in 5 hours. Mycobacteria are also sensitive to hydrogen peroxide. Tubercle bacillus dies when heated: within 20 minutes at 60 ° C and within 5 minutes at 70 ° C.
The office can cause the disease after two to three years of asymptomatic existence and for a long time to excite anti-tuberculosis immunity in the body.
What is tuberculosis?
As noted earlier, tuberculosis is an infectious disease caused by the activity of mycobacteria. For the most part, the disease spreads by airborne droplets from an infected person to a healthy person upon contact (coughing, sneezing, talking). Sometimes infection can be of a food nature (raw milk).
At risk are people who are constantly in rooms with unsuitable sanitary conditions - prisons, homes for the homeless. This also includes patients with weakened immunity (HIV-infected, cancer patients). Diabetes patients babies the elderly; family members with tuberculosis; smokers people with poor nutrition - these categories of citizens are most often attacked by tubercle bacillus. The method of nutrition involves the mandatory consumption of vitamins and minerals that help restore reduced immunity functions.
The incidence of tuberculosis is due to the individual characteristics of the body, and is also directly related to the psychological state of a person. The age group is dominated by a group of people aged 18–26.
The peculiarity of this pathology is that the tubercle bacillus quickly becomes resistant to medications, therefore 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 healthy body does not allow the office 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. World Tuberculosis Day is March 24th.
Tuberculosis transmission routes
There are four main ways in which the tubercle bacillus spreads:
- airborne, when mycobacteria fall into the air with droplets when coughing, sneezing the patient;
- Alimentary - infection occurs through the gastrointestinal tract;
- contact - infection occurs through the conjunctiva of the eye (infection through the skin is a rare occurrence);
- intrauterine - infection through the affected placenta during childbirth from mother to baby.
In a healthy 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 of toxins, “protection” does not work. The probability of infection by an alimentary route depends on the state of the intestinal wall, its absorption capacity.
Since the tubercle bacillus is located outside the cell and multiplies slowly, the tissues retain their healthy structure for some time, however, after some time, mycobacteria with lymph flow enter the lymph nodes and spread throughout the body. The most favorable for mycobacteria are organs with a developed microvasculature (lungs, cortical layer of the kidneys, sections of the fallopian tubes). As soon as the MBT penetrate into the cell, they begin to damage its structure and divide.
Pathology anatomy
In organs affected by infection, 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 slowed growth of the office, the inflammatory reaction disappears, however, the pathogen from the focus of inflammation is not completely eliminated.
Tubercle bacillus in the body persists for a long time, and a person can be a carrier of the office throughout life. With weakened immunity, 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 of a disease will decrease.
With weakened immunity, the body is not able to withstand the multiplication of bacterial cells, which occurs exponentially. For the life of MTB, a special favorable environment is formed in which isolated granulomas merge into the total volume, while they say 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., is most often asymptomatic. Only one out of ten cases goes into the active phase. The tuberculosis bacillus mostly affects the lungs, but can also affect other body systems.
There are two forms of tuberculosis:
With an open form, the presence of tubercle bacillus is easily detected in sputum or in other secretions of the patient (urine, feces). Non-compliance with hygiene precautions with 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 the tubercle bacillus, pathology is classified into:
- pulmonary tuberculosis,
- extrapulmonary tuberculosis.
Depending on how the pathology has spread in the body, there are:
- latent tuberculosis,
- disseminated tuberculosis,
- focal tuberculosis,
- caseous pneumonia,
- tuberculoma
- fibrocavernous tuberculosis,
- cirrhotic tuberculosis,
- tuberculosis of the pleura, larynx or trachea is a rare phenomenon.
Extrapulmonary tuberculosis affects any other organ, according to which pathology is classified into:
- tuberculosis of the central nervous system and meninges - the disease affects the spinal cord and the dura mater of the brain;
- digestive system organs, in which, as a rule, the small and cecum are affected;
- genitourinary tuberculosis affects the kidneys, urinary tract, genitals;
- bone structures;
- lupus;
- tuberculosis of the eyes.
Clinical manifestations of pathology. CNS tuberculosis
As mentioned earlier, due to the fact that the tubercle bacillus divides extremely slowly, it is impossible to detect it at the earliest possible date. Therefore, the pathology may not manifest itself for a long time, and later reveal itself by chance during fluorography or tuberculin tests. Moreover, specific signs of the disease, in fact, do not exist. The fact that intoxication occurs in the body can be indicated by pallor of the skin, chronic fatigue or lethargy, apathy, a slight increase in body temperature (about 37 ° C), increased sweating, decreased body weight, and an increase in lymph nodes.
A laboratory blood test of patients with tuberculosis reveals a lack of iron, a decrease in the number of leukocytes. Later, when the disease enters a more active phase, obvious signs of the pathology of the affected organ will join the above symptoms.
If mycobacteria affects the central nervous system, then the patient has, in addition to high fever, sleep disturbance, aggression, severe headaches, and 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 muscles of the neck and the inability to press the chin to the chest, 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 occurrence of mental disorders against this pathology, as well as impaired consciousness, sensitivity, and movement of the eyeballs.
In contrast to the disease in an adult, 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. Subjected to this pathology most often children who are in unsanitary conditions, eat poorly, constantly overwork. Tuberculosis bacillus in children causes specific symptoms in the body, so the attention of parents should attract 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 human body, for example, 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 arise due to the complicated course of pulmonary tuberculosis. Another complication of pulmonary tuberculosis can be upper respiratory tract tuberculosis, when the pharynx and larynx are involved in the inflammatory process. Symptoms of such a disease in addition to the above are hoarseness or difficulty swallowing.
The defeat of Koch's bacillus lymph nodes is called tuberculous lymphadenitis. Most often, supraclavicular or cervical lymph nodes are exposed, which are enlarged, but painless.
MTB can affect the genitourinary system. The disease is manifested by sharp pains in the lower back or back, high body temperature. When urinating, spotting is possible. Pathology occurs in equal proportions in both women and men.
Bone tuberculosis is characterized by frequent fractures, severe pain in the affected area, and the inability to move normally. Launched forms of such a 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. Analysis of the smear, however, cannot be called a reliable and unambiguous method, since in the early stages of the pathology, as well as in the case of manifestations of the disease in children, the study gives a negative result.
Radiographic 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 called the Mantoux reaction in the common people.
The main task when choosing a treatment regimen for a patient is to study the drug resistance of the pathogen, that is, the sensitivity of the mycobacteria culture grown in laboratory conditions to medications.
Today, the main method for treating tuberculosis is anti-tuberculosis chemotherapy, which is multicomponent. 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 (PASK). This scheme is classic, however, today it is rarely used due to the high toxicity of PASK. In a four-component method, Rifampicin (Rifabutin), Isoniazid, Pyrazinamide, Ethambutol are used. Many medical centers use an even more advanced technique - a five-component scheme, which, in addition to the above four drugs, uses Ciprofloxacin.
I must say that tuberculosis is an insidious disease, the development of which in the human body is caused precisely by tuberculosis bacillus. Treatment should be immediate and correct, because in the absence of therapy, 50% of cases end with death from pathology. A fatal outcome 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 who has chronic tuberculosis is dangerous for others, as it releases mycobacteria into the environment.
Prevention
Perhaps, BCG vaccine, which effectively protects against one of the most dangerous forms of tuberculosis - tuberculous meningitis, can be attributed to preventive measures against tuberculosis today. According to the National preventive vaccination calendar, a child is vaccinated even in the hospital in the first 3–7 days of life. Further, at 7 and 14 years of age, revaccination is carried out subject to a negative Mantoux reaction and the absence of contraindications.
The BCG vaccine (Bacillus Calmette-Geren) shows an excellent result, however, mandatory vaccination against tuberculosis is not accepted in all countries of the world, it all depends on the incidence of tuberculosis in the region. A few months after vaccination, a skin reaction appears at the injection site - a small seal.
Vaccination is contraindicated in a child if:
- the newborn is diagnosed with immunodeficiency, as well as when there are persons in the infant's family suffering from this pathology;
- siblings of the newborn had complications after a similar vaccination;
- the child has congenital pathologies of the central nervous system.
Vaccination is delayed if:
- the baby is not full-term,
- he has any infectious disease
- 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 healthy and proper. Excessive 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 membrane contains many fats. A person with a pathology needs food rich in proteins, carbohydrates, vitamins and minerals.
To minimize the likelihood of a primary infection at home, you must follow the rules of hygiene, spend more time in the fresh air, hang out woolen and cotton products in the sun.