Tuberculosis is an infectious disease that occurs due to Koch bacilli entering the human body. The disease is dangerous because it affects the respiratory system. Less commonly susceptible to tuberculosis are the bones, skin, lymphatic, genitourinary, nervous, lymphatic systems, as well as other organs and systems.
The immune system (the body's natural defense against infection and disease) of most healthy people kills the bacteria without causing symptoms. Sometimes the immune system cannot kill bacteria, but can stop it from spreading in the body. In this case, no symptoms develop, but the bacteria remain in the body. This is called latent (hidden) tuberculosis.
Methods of transmission
- Airborne - through the sneezing, coughing of a patient with an open form of the disease, and even when drying out, the bacillus retains its pathogenicity.
- Alimentary – through the digestive tract. The infection enters the body due to poor hand hygiene or poorly washed and unprocessed food.
- Contact – the infection enters a person through the conjunctiva of the eyes, through kissing, sexual contact, through contact of contaminated objects with human blood, or the use of other people’s hygiene items.
Tuberculosis: routes of transmission, forms, symptoms
Contents Routes of transmission of tuberculosis
Latent tuberculosis
Symptoms and testing of tuberculosis
Tuberculosis ranks first in mortality among infectious diseases. According to WHO, 10 million cases of the disease are registered annually in the world. About 2 million tuberculosis patients die without receiving the necessary treatment. The vast majority of people affected by tuberculosis live in countries with low standards of living, income and health care. 80% of tuberculosis cases are registered in 22 countries of the world, which includes Russia. The remaining 197 countries are practically free of it.
In 2014, the UN Assembly proclaimed a declarative goal to eradicate tuberculosis by 2035. The goal is to reduce the number of new cases of tuberculosis by 90% and create an environment in which no family bears the catastrophic costs of treating the disease. Humanity planned to defeat tuberculosis back in the last century: in the middle of the 20th century, effective anti-tuberculosis drugs were invented, and it seemed that eradicating tuberculosis from the planet would take two or three decades. However, everything did not go according to the optimistic scenario.
The fact is that Mycobacterium tuberculosis
) is capable of mutating under unfavorable conditions. It adapts well to external factors, including medications when used incorrectly. More and more people on the planet are becoming ill with multidrug-resistant mycobacterium tuberculosis.
According to WHO, Russia is among the 27 countries with the largest number of patients with drug-resistant tuberculosis. More such patients live only in China and India.
Based on the volume and nature of the lesion, there are two main types of tuberculosis - pulmonary and extrapulmonary. Mycobacterium tuberculosis can affect not only the lungs and bronchi, but also bones, joints, intestines, lymph nodes, membranes of the brain and other organs. An epidemic danger is posed by a patient with tuberculosis whose sputum contains mycobacteria, especially if he does not yet know about his disease and does not receive treatment. In the closed form, when Mycobacterium tuberculosis is not detected in sputum tests, there is practically no risk of transmission of infection from the patient (it is not necessary to wear a respirator when contacting such patients).
Routes of transmission of tuberculosis
In total, there are four classical routes of transmission of tuberculosis: aerogenic (airborne and airborne dust), nutritional, through the digestive tract (for example, through infected milk or meat of a sick animal), contact (through the conjunctiva and damaged skin) and vertical (from mother to fetus).
An aerogenic route of transmission is possible through coughing, sneezing, loud singing, when mycobacteria enter the air inside droplets of an infected aerosol sprayed by a patient. Then the mycobacteria contained in these drops enter the body of a healthy person with the air flow. But this does not mean that a person will definitely get sick. Most often, the well-coordinated work of the immune system does not allow mycobacteria to enter the body. And even if this happens, it causes minimal local inflammation, which does not develop into a disease. This is how a condition is formed that we call latent tuberculosis infection.
Infection through a book that a person with tuberculosis could sneeze on is more of a myth. Even if a book contains viable mycobacterium, it is unlikely to penetrate into the deep lungs of another person.
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The most serious case of nutritional transmission of tuberculosis occurred in the German city of Lübeck in 1930, in the era before the advent of anti-tuberculosis drugs. At that time, the BCG vaccine (Bacillus Calmette-Guérin, a vaccine against tuberculosis) was administered orally in the form of drops. During routine vaccination, 240 newborns were mistakenly given a virulent culture of Mycobacterium tuberculosis instead of BCG. As a result of infection, all children fell ill, 77 of them died from tuberculosis. Some children remained clinically healthy, but a long period of observation showed that all of them had suffered tuberculosis. A few years later, large calcifications (accumulations of calcium salts) in the abdominal lymph nodes began to be detected in children, which indicated previous tuberculosis.
Now it is almost impossible to become infected with tuberculosis through a vaccine: the live attenuated mycobacterium of the artificially isolated BCG strain, which is used to create the vaccine, has practically lost its virulence for humans.
Currently, the tuberculosis vaccine is available in dark glass bottles in the form of a powder, which must be diluted with a solvent before administration. The appearance of the bottle and the procedure for preparing the vaccine, storage conditions minimize the likelihood of confusing it with other drugs.
Contact and vertical routes of infection with tuberculosis are extremely rare in practice. For example, the medical literature describes cases where a pathologist, while opening the corpse of a person who died of tuberculosis, injured the skin, and subsequently developed skin tuberculosis at the site of the cut. For a vertical route of infection to occur, the mother's placenta must be affected by tuberculosis, and this organ is evolutionarily well protected from infection.
Latent tuberculosis
According to WHO experts, approximately a third of the world's population is infected with Mycobacterium tuberculosis, that is, they have a latent tuberculosis infection. Latent tuberculosis infection (LTBI) is defined as a state of persistent immune response to Mycobacterium tuberculosis that has previously entered the body. People with latent TB infection are not contagious, but they have an increased risk of developing active TB disease.
Let’s say a person came across a patient with tuberculosis, the mycobacterium entered his lungs and “fell asleep.” In the body, the immune system became “acquainted” with the mycobacterium, and it acquired an immunological memory for this pathogen. In the future, this knowledge will allow a person to more easily fight tuberculosis infection if it is activated or a new infection occurs. Usually for a person such a “meeting” goes unnoticed.
Sometimes, during an X-ray examination, small calcifications are found in the lungs and intrathoracic lymph nodes of a person with LTBI. However, more often these changes are so minimal that they do not appear either clinically or radiologically. LTBI is detected using immunological tests, which include the Mantoux test, Diaskintest and interferon gamma release tests (IGRA tests).
WHO recommends testing for latent tuberculosis infection in people at risk: people with HIV infection, people in contact with people with tuberculosis, patients on dialysis, patients preparing for organ transplantation, and patients with silicosis. In this situation, activation of latent tuberculosis can be prevented by chemoprophylaxis with anti-tuberculosis drugs.
Important
German scientist and researcher Robert Koch, after 17 years of work in the laboratory, discovered the causative agent of tuberculosis during a microscopic examination of the sputum of an infected person. Subsequently, he isolated a pure culture of the pathogen and used it to cause tuberculosis in experimental animals. On March 24, 1882, the researcher read a report “The Etiology of Tuberculosis” at the Berlin Pathological Physiological Society. Now the date March 24, at the initiative of WHO, has been declared World Tuberculosis Day. Robert Koch received the Nobel Prize for his discovery of the causative agent of tuberculosis.
Symptoms and testing of tuberculosis
Tuberculosis is not characterized by an acute onset. The doctor will ask the patient: “How long have you been sick?” “Well, I don’t remember anymore,” he will think, “It’s been a long time.” Two, three, a month, six months ago.” Clinical manifestations of tuberculosis are more often found in the form of mild symptoms, such as cough, sweating, fever, and weight loss. A cough lasting more than three weeks is the main symptom by which pulmonary tuberculosis can be suspected.
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In addition to coughing, a person may experience sweating, especially at night, weakness, as well as a temperature that rises mainly in the evening and rarely reaches 38°C. It cannot be said that a patient with tuberculosis feels very well, but he remains able to work, and he can go to work for a long time even with the disease. It is not entirely easy to understand that these symptoms are signs of tuberculosis, since they are often present in other diseases.
The most contagious patient is a person who does not yet know about his disease. He is sick, but does not yet know that he poses a danger to others, and accordingly, does not take the necessary measures to prevent the disease.
To understand whether a person has tuberculosis or not, it is necessary to conduct an X-ray examination and sputum testing for Mycobacterium tuberculosis. The examination can be carried out in a clinic using microscopy with Ziehl-Neelsen staining. The “gold standard” for diagnosing tuberculosis is the culture of sputum on nutrient media; such a study is carried out in a TB institution.
In our country, to detect tuberculosis before clinical manifestations, all adults and adolescents, starting from the age of 15, undergo a fluorographic examination at least once every two years. People with an increased risk of the disease - more often. For children and adolescents, screening for tuberculosis is carried out once a year using immunological tests: Mantoux test up to 8 years, after - Diaskintest.
Continuation of the article - read the link.
Recorded by Diana Karliner
The second part of the article talks about vaccination against tuberculosis, tuberculosis and smoking, and the stay of a patient with this infection in a hospice.
Types of tuberculosis
- Open form - the disease is clearly expressed, bacteria are easily detected in sputum and feces. The patient himself poses a danger to others, since the infection is transmitted by airborne droplets. Microbacteria can be found in sputum, urine, and feces.
- Closed form - not dangerous to others. Characterized by the difficulty of detecting infection in sputum. The most common tuberculosis is pulmonary tuberculosis, but this infection can also affect bones, joints, genitourinary system, intestines, peritoneum, meninges, central nervous system, peripheral lymph nodes, skin
Asymptomatic course of the disease
For a long time, pulmonary tuberculosis may be completely asymptomatic, or several mild symptoms may be present. Disseminated tuberculosis mainly manifests itself as a consequence of pneumonia, but most often, the disease is latent (latent form) and does not manifest itself. In this case, the disease can be detected by chance during standard annual examinations: X-rays, fluorography, Mantoux test.
The symptoms of a dangerous disease can often be confused with the usual symptoms of bronchitis, pneumonia or ARVI. In this case, the main sign that you should pay attention to is the presence of symptoms for a long time or the lack of improvement after treatment.
The first symptoms of tuberculosis
In the early stages, the disease is practically asymptomatic. As it develops, the patient's condition worsens, but no specific symptoms are observed. Increased fatigue, weakness, sudden weight loss for no apparent reason, a temperature of 37-38 ° C that does not subside for a long time, and night sweats appear. In children, the disease progresses faster than in adults.
The pulmonary form of tuberculosis is accompanied by a cough. Mild at first, it begins to progress over time. If your cough continues for more than three weeks, you should seek medical help immediately. The cough is initially dry, paroxysmal, especially at night and in the morning. Later, yellow-green sputum begins to be released, and at the cavity stage, hemoptysis is observed.
In the form of tuberculosis that affects the brain and its membranes, in addition to symptoms of general intoxication, sleep disturbances and headaches are observed, the intensity of which gradually increases.
Manifestations of tuberculosis in infants
If an adult can recognize and understand a disease himself, then how can a serious disease be detected in infants? The characteristic primary signs of tuberculosis in infants and newborns are increased body temperature, impaired or complete lack of appetite, and difficulty breathing. The child may also experience other symptoms, depending on the organ affected. For example, the liver and spleen may be increased in size, since these are the organs that filter tuberculosis bacteria. In addition, an infected baby does not gain weight well. Therefore, it is very important to monitor the behavior of infants and young children in order to detect infection early.
How is tuberculosis diagnosed?
To diagnose the disease, you must first consult with your primary care physician, who, if tuberculosis is suspected, will refer you to a phthisiatrician (tuberculosis specialist) for further diagnosis and treatment. Diagnosis will depend on the type of disease.
Diagnosis of pulmonary tuberculosis
An X-ray of the chest is required, which provides an image of the lungs. For pulmonary TB, the scan should show changes in the appearance of the lungs, such as scarring.
To confirm the diagnosis, samples of mucus and sputum are taken and analyzed under a microscope for the presence of tuberculosis bacteria.
Examination for extrapulmonary tuberculosis
- CT scan
- magnetic resonance imaging (MRI)
- ultrasound examination (ultrasound)
- blood tests
- Analysis of urine
- biopsy - a tissue sample is taken from the affected area to be tested for the presence of tuberculosis
Examination for latent tuberculosis
To prevent the disease, every person is required to undergo fluorography and an X-ray of the lungs at least once every two years.
How to treat tuberculosis?
Treatment of the pathology depends on its type, but most often a course of antibiotics is prescribed. Tuberculosis is a dangerous disease that requires immediate treatment. This allows the person to return to their normal lifestyle.
Antibacterial therapy is aimed at suppressing the proliferation of the tuberculosis pathogen.
Treatment takes place in 2 phases: in the first, several drugs are used at once to reduce the population of microbacteria, the second phase is maintenance therapy. Antibiotics stop the proliferation of bacteria and their release into the environment, the inflammatory process.
After taking such potent medications, a person needs additional supportive therapy that will strengthen the body and reduce the toxic effect. For this, immunostimulants (restore liver function), sorbents (remove toxic breakdown products of chemotherapy drugs) and vitamin complexes are prescribed.
After taking the drugs for two weeks, most people are no longer contagious and feel much better. However, it is very important to continue taking your medications as directed by your doctor and complete your entire course of antibiotics.
Other treatments for tuberculosis
Surgery
The goal of therapy is the elimination of tuberculosis foci in the lungs with ineffective treatment, elimination of the consequences of pulmonary tuberculosis, and elimination of organ damage. All this is necessary to prevent the recurrence of the disease and to exclude the occurrence of complications.
Indications for surgical intervention can be any form of respiratory tuberculosis, especially in the case of complications that threaten a person’s life.
Chemotherapy
used with an optimal combination of anti-tuberculosis drugs aimed at eliminating mycobacteria and suppressing their reproduction. The duration of such treatment can reach up to a year - it all depends on the form and stage of development of the pathology.
If chemotherapy is stopped early, exacerbation or complications of tuberculosis may occur. Therefore, it is important to follow all doctor's recommendations. And the doctor, for his part, must draw up a detailed treatment plan and make adjustments throughout the entire therapy.
A patient who is indicated for chemotherapy as a treatment for tuberculosis must be prepared for the negative consequences of such an aggressive method. Side effects on the action of medications often occur. There are 2 types of adverse reactions: toxic and allergic. Dysbacteriosis may also occur.
The doctor may prescribe outpatient treatment if the disease is detected at an early stage and there is no infection to others. In this case, you need to regularly visit your doctor and undergo diagnostics. Most often, the patient is transferred to outpatient treatment after observation in a hospital and undergoing an extensive course of therapy in a tuberculosis clinic. At this time, the patient is no longer contagious.
Manifestations of infection of the upper respiratory organs
Signs of infection may appear in different respiratory organs. To recognize the disease in time, you should know its symptoms. At the beginning of the development of tuberculosis, the patient develops dryness and soreness in the nose and oropharynx, and he cannot swallow food normally. In addition, there is severe shortness of breath and a hoarse cough.
After some time, severe chills appear, body temperature rises, and breathing becomes difficult. After another period, the voice changes and hemoptysis begins. At the same time, patients lose a lot of weight because they cannot eat properly due to pain.
Tuberculosis of the larynx is manifested by improper mobility of the vocal cords and leads to hoarseness, breathing problems, soreness, and changes in voice.
When the throat is affected, there is severe pain, a sensation of a foreign body in the throat, increased salivation, swelling, rashes and redness of the pharynx mucosa. If we are talking about nasal tuberculosis, then all the symptoms are very similar to ordinary sinusitis: itching, burning, crusts in the nose, frequent bleeding, congestion, pain, the presence of mucopurulent discharge.
Symptoms may be constant, come and go, or progress slowly (sluggish tuberculosis). Rapid progress is also common, when a person can die from the manifestations of the disease in a few weeks.
