Tuberculosis has long ceased to be the most common disease, but it still poses a great danger to people. About a third of the population is a carrier of a causative bacterium that can be transmitted from person to person through the air. Therefore, it is extremely important to diagnose tuberculosis in time and take all measures to cure it. You can read more about the laboratory diagnosis of tuberculosis, the microbiology of this disease and its treatment in this article.
Tuberculosis
What is tuberculosis? This disease is caused by a special bacterium, Mycobacterium tuberculosis. It overcomes the defense of the immune system and begins to multiply uncontrollably. As a result, the infection infects the human lungs, causing tissue breakdown and serious damage to the internal organ. At a certain period of the development of the disease, a person becomes infectious, while no obvious symptoms may appear for a while. Since tuberculosis is transmitted by air, such a patient becomes dangerous for many people and before they detect the disease, he manages to infect many healthy people. Moreover, almost a third of all people on our planet have bacteria in their bodies that cause tuberculosis. It's just that their immunity is strong enough to restrain their growth. Such passive carriers cannot infect others until the disease becomes acute. Tuberculosis can be transmitted not only from person to person, but also through infected products, in particular, poultry and animal meat. In order to avoid an epidemic among the population, there is a laboratory diagnostic method for tuberculosis GOST 26072-89, which allows you to identify the presence of the pathogen in time.
Tuberculosis is more prevalent in some countries than in others, and various factors can affect it. For example, the spread of HIV can also cause an increase in tuberculosis infection, since secondary human immunodeficiency makes the patient's body open to all sores. For example, in the United States, tuberculosis reached its highest prevalence in 1985. By 1993, thanks to strong state support, the number of cases of infection was reduced, but the number of patients worldwide is still alarming. Laboratory diagnosis of tuberculosis in adults is extremely important, as it allows you to identify different forms of tuberculosis at the initial stage. As a result, the patient receives sufficient treatment, and people in contact with him avoid the danger of infection.
Methods for the diagnosis of tuberculosis
This disease is dangerous. It is very difficult to identify using only one research method. Therefore, most often doctors resort to differential diagnosis of tuberculosis, which includes several methods and allows you to accurately establish the diagnosis. What are the main diagnostic methods that can be identified?
- Fluorography can detect the presence of the disease according to the changed pattern of the lungs.
- Medical history - a study of the patient’s medical history, his complaints, questionnaires. This method alone is not a basis for making a diagnosis, but an experienced specialist, together with other methods, can quickly find out the reason for feeling unwell.
- Examination of the patient - listening to the lungs and percussion can detect wheezing and other respiratory disorders.
- Laboratory diagnostics are carried out on the basis of analyzes and are aimed at identifying the pathogen and atypical reactions of the body (for example, inflammation).
Laboratory and instrumental diagnosis of tuberculosis in children is a rather difficult task, since the diagnosis is difficult to confirm using microscopic examination, and the symptoms are often blurred and similar to other diseases. That is why children at school and in kindergartens are often given a Mantoux test, which shows whether there is an immune response to the introduced bacteria.
Laboratory diagnosis of tuberculosis
This method is a type of clinical diagnosis and allows you to identify the presence of the disease by a change in the chemical and quantitative components of human tissues. For laboratory diagnostics, the following fluids can be taken as materials for research:
Modern methods of laboratory diagnosis of tuberculosis involves the use of all methods at the same time if a quick and clear response is needed. Indeed, in some situations, the bill can go for hours. A timely diagnosis can help prescribe the right treatment and save the patient’s life. Laboratory diagnosis of tuberculosis includes several methods, each of which has its pros and cons.
Microscopic method
The microscopic method allows you to establish the presence of bacteria in the body using reagents that, when exposed to the causative agent of tuberculosis, become colored in a certain color. For example, if Mycobacterium tuberculosis is found in excess in the amount in the body, the contrast becomes red. To speed up the microscopy procedure, the luminescent method is sometimes used, which allows the pathogen to be detected much faster. In this case, alien organisms are highlighted with blue or green light. Despite the advantages in the form of a quick result and relatively simple, the microscopic method is not considered ideal. He rarely shows the exact result. If a person is sick with tuberculosis, but the number of pathogens is not enough to affect the color of contrast, then the disease can easily be skipped. However, this method is still used in some public institutions.
Bacteriological method
Among the laboratory methods for diagnosing tuberculosis, the bacteriological method should be noted, since it is used most often. For this analysis, sputum from the lungs, which is always present with pulmonary tuberculosis, is taken as the test material. Since it contains many bacteria and fungi, it can take up to eight weeks to identify a specific group of microorganisms. During this time, the laboratory technician usually performs the following procedures:
- Isolates bacteria from the original sample.
- Sows bacteria and grows a pure culture, studying its properties. This process takes the longest time, since microorganisms take time to reproduce.
- Examine cells in detail.
In order for the bacteria not to die, they are placed in a special nutrient medium in which they feel exactly the same as in the human body. When is the bacteriological method most often used? Usually it is used in cases where the diagnosis is already pre-established and only needs additional confirmation. The bacteriological method is one of the most accurate methods, but, unfortunately, the speed of response is poor.
Mantoux test
The Mantoux test is the earliest type of diagnosis of tuberculosis. It was invented back in 1908. This is an easy and quick way to understand if a person has tuberculosis. In large groups (especially children), the patient can serve as a source of infection for everyone else. That is why the Mantoux test is most often given prophylactically to children once a year. If there are symptoms of tuberculosis, tuberculin can be re-administered.
During the study, a tuberculosis pathogen antigen is administered under the skin in the patient’s hand. It is not dangerous to the human body and certainly can not infect it. The procedure is carried out using a special small needle and practically does not cause any pain. If there are pathogens of tuberculosis in your body, then a large red spot will form at the injection site, exceeding the accepted norms. The specialist usually measures it with a ruler. If a pathology is detected, then the person is sent for an additional examination. An increase in the Mantoux reaction alone cannot be considered a basis for making a diagnosis. But a too small Mantoux size is also not a positive result, as this may indicate problems with immunity.
In order for the research method to show as clear a result as possible, after subcutaneous administration of a tuberculin test, several rules must be observed:
- do not scratch the injection site;
- Do not wet it.
If the recommendations were not followed, then it is necessary to tell the doctor about this, as this can distort the results of the studies.
Serological method
Serological methods for diagnosing tuberculosis have also come to us from the 20th century. However, after numerous tests, scientists realized that, unlike all other infections, the serological method for tuberculosis does not have the necessary sensitivity and cannot guarantee an accurate diagnosis. That is why, after analyzing the methods of laboratory diagnosis of tuberculosis, the serological method was not recommended by specialists for mass use. Perhaps in the near future cheaper and more effective methods of serological diagnostics will be created that will be able to detect specific tuberculosis antigens, but so far other methods have been used in medicine.
PCR
The PCR method is currently considered one of the most effective laboratory methods for the early diagnosis of tuberculosis. What is he like? The polydimensional chain reaction allows one to achieve a significant increase in some DNA fragments and to visually evaluate its components. This method was developed in 1983 by the scientist Carey Mullis, and in the XXI century it continues to be used throughout the world. In addition to a simple increase, PCR allows you to perform some other manipulations that are also able to give certain information about the human body.
PCR has proven itself as a diagnostic method, so it is often used both separately and in combination with other studies. Any liquid can be taken for analysis, but most often the patient's saliva or sputum is examined. If we are talking about meningitis caused by tuberculosis, then in this case they take cerebrospinal fluid. The main advantage of this method is that it has a high sensitivity and can detect even the minimum concentration of tubercle bacillus. In addition, the result can be obtained very quickly - usually the answer appears within 24 hours.
Cytology and histology
Unfortunately, in medical practice, there are quite often cases in which the presence of a clinical picture of tuberculosis, an x-ray also shows changes in the structure of tissues, but it is impossible to establish the exact cause of the ailment from the analysis. Meanwhile, without laboratory confirmation, it is impossible to correctly prescribe treatment. In these cases, a histological or cytological method can be used for research .
Histological examination is an analysis of tissue, which is carried out under high magnification. For diagnosis, a lung biopsy is most often taken. Tissue is taken using a small cut. This operation can be quite painful, so it can only be done if there is a clear indication.
Cytological examination of sputum is considered in many cases mandatory when making a diagnosis. Dried and pre-stained smears are examined at high magnification. In patients with tuberculosis, purulent-mucous formations foreign to a healthy lung can be considered on them. An accumulation of monocytoid mononuclear cells is also noted. Two of these techniques - cytology and histology are highly informative for specialists, but at the same time do not require large material or time costs, therefore they are used quite often.
Tuberculosis symptoms
You may be a carrier of the bacterium that causes tuberculosis, but if your immunity is quite strong, then you will not get sick. The so-called latent tuberculosis is not contagious and does not pose a danger to others. But for the patient himself, the latent form of tuberculosis is not a good option, as it can become active at any time. Such a person is a kind of time bomb, which can be activated at any time. That is why treatment is the same for both latent and active forms. What are the main symptoms of tuberculosis?
- A cough that does not go away for more than three weeks.
- Spotting from the lungs (coughing up blood).
- Weight loss for no particular reason.
- Chest and breathing pain.
- Fever.
- Sweating and weakness.
- Chills.
- Loss of appetite.
Tuberculosis can affect not only the lungs, but also other internal organs: for example, the kidneys, spine and brain. If tuberculosis spreads outside the lungs, the symptoms may vary depending on the location of the bacteria. For example, spinal tuberculosis can make you feel back pain, and kidney tuberculosis can lead to increased urination. However, most often tuberculosis begins in the lungs, so the symptoms in patients are similar to each other.
Reasons and Prevention
An analysis of bacteriological methods for laboratory diagnosis of tuberculosis shows that this method is very effective for the treatment and prevention of the development of active tuberculosis. But it is not always possible to find effective treatment, especially in the later stages of the disease. Therefore, doctors prefer to prevent the disease and insist on various preventive methods. What can cause tuberculosis?
It appears from only one mycobacterium, which is transmitted from the patient during a conversation, sneezing or laughing. This is enough for the interlocutor to catch the disease. But the chances of getting infected from a stranger are minimal. A much greater danger is represented by people who do not know about their disease, but who are in close contact with you. However, you can take the following measures to prevent the development of the disease:
- Avoid public places and crowds.
- Wear a special mask.
- Check periodically.
All of these methods work for only a third. Since we all live surrounded by other people, it is not possible to completely avoid contact with them. Wearing a mask can reduce the risk of infection. Therefore, all that is actually in our hands is to take care of our health and notice the warning symptoms in time. Especially should be careful people who have the following diseases:
- diabetes;
- HIV
- cancer;
- kidney disease
- critically low body weight.
Timely differential diagnosis of tuberculosis helps increase the chances of a full recovery and protects your loved ones from infection.
Facts
Here are some facts about tuberculosis that will make you think.
- Tuberculosis is one of the three main causes of death for patients aged 15 to 44 years.
- According to WHO estimates, approximately nine million people a year suffer from tuberculosis, of which three million will never know about their disease.
- Symptoms of tuberculosis, such as sweating, weight loss and low fever, may be mild for many months, during which people can infect about 10-15 people.
- Tuberculosis is a pathogen that can be transmitted from person to person exclusively through the air.
Treatment
Diagnosis and treatment of tuberculosis is critical to maintaining good health. Indeed, without treatment, 2/3 of patients die. However, with timely administration of drugs, the disease is curable in 100% of cases. Antibiotics are used in the early stages, and surgery may be required in the later stages. In some cases, tuberculosis bacteria can mutate into an infection that is unresponsive to standard drugs. Then a longer treatment with new generation drugs, which are not available in all countries, will be required. Also, after treatment, relapses often occur, which require a second course of medication. . .
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