Pulmonary tuberculosis is an infectious pathology caused by Koch’s bacillus, characterized by clinically and morphologically different variants of lung tissue damage. The variety of forms of pulmonary tuberculosis determines the variability of symptoms. Respiratory disorders (cough, hemoptysis, shortness of breath) and symptoms of intoxication (prolonged subfebrility, sweating, weakness) are most typical for pulmonary tuberculosis. Radiation, laboratory tests, and tuberculin diagnostics are used to confirm the diagnosis. Chemotherapy is carried out with special tuberculostatic drugs; surgical treatment is indicated for destructive forms.
ICD 10
A16.0 A16.1 A16.2
Meaning
Pulmonary tuberculosis (PT) is a disease of infectious etiology that occurs with the formation of specific inflammatory foci in the lungs and a general intoxication syndrome. The incidence of disease has an ancient history: tuberculosis infection was known to representatives of early civilizations. The former name of the disease “phtisis” in Greek means “consumption, exhaustion”, and the doctrine of tuberculosis was called “phthisiology”.
To date, PT is not only a medical and biological, but also a serious socio-economic problem. According to WHO, every third inhabitant of the planet is infected with tuberculosis, the mortality rate from infection exceeds 3 million people per year. Disease is the most common form of tuberculosis infection. The proportion of tuberculosis of other localizations (joints, bones and spine, genitals, intestines, serous membranes, central nervous system, eyes, skin) in the structure of morbidity is significantly lower.
Causes
Characteristics of the pathogen
Mycobacterium tuberculosis (MBT) are the specific agents responsible for the infectious nature of the disease. In 1882. Robert Koch first described the basic properties of the pathogen and proved its specificity, so the bacterium received the name of its discoverer – Koch’s wand. Microscopically, Mycobacterium tuberculosis has the form of a straight or slightly curved fixed rod, 0.2-0.5 nm wide and 0.8-3 nm long.
A distinctive feature of MBT is their high resistance to external influences (high and low temperatures, humidity, acids, alkalis, disinfectants). The pathogens of pulmonary tuberculosis demonstrate the least resistance to sunlight. Tuberculosis bacteria of human and bovine type are dangerous for humans; cases of infection with avian Mycobacteria are extremely rare.
Ways of infection
The main route of infection in primary forms is aerogenic: mycobacteria spread from a patient with an open form of a person with mucus particles released into the environment when talking, sneezing, coughing; they can dry out and spread with dust over considerable distances. Infection often enters the respiratory tract of a healthy person by airborne droplets or dust.
Alimentary (when eating infected foods), contact (when using common hygiene items and utensils) and transplacental (intrauterine) pathways play a lesser role in infection. The cause of secondary pulmonary tuberculosis is the re-activation of a previously transmitted infection or re-infection.
Risk factors
However, the ingestion of MBT in the body does not always lead to disease. Factors against which pulmonary tuberculosis develops especially often are considered to be:
- unfavorable social and living conditions
- smoking and other chemical addictions
- insufficient nutrition
- immunosuppression (HIV infection, taking glucocorticoids, condition after organ transplantation)
- silicosis
- diabetes mellitus
- CPN
- oncological diseases, etc.
Migrants, prisoners, people suffering from drug and alcohol addiction are at risk for the development of pulmonary tuberculosis. The virulence of the infection and the duration of contact with a sick person also matters.
Pathogenesis
With a decrease in local and general protective factors, mycobacteria freely penetrate into the bronchioles, and then into the alveoli, causing specific inflammation in the form of individual or multiple tuberculous tubercles or foci of curd necrosis. During this period, a positive reaction to tuberculin appears – a turn of the tuberculin sample. Clinical manifestations of pulmonary tuberculosis at this stage often remain unrecognized. Small foci can dissolve, scar or calcify on their own, but MBTs persist in them for a long time.
The “awakening” of infection in old tuberculosis foci occurs when confronted with exogenous superinfection or under the influence of unfavorable endo- and exogenous factors. Secondary pulmonary tuberculosis can occur in an exudative or productive form. In the first case, perifocal inflammation develops around the initial focus; in the future, infiltrates may undergo decay, melting with the rejection of caseous masses and the formation of caverns. With productive forms of the tuberculosis process, connective tissue grows in the lungs, which leads to pulmonary fibrosis, bronchial deformity, and the formation of bronchiectasis.
Classification
Primary pulmonary tuberculosis is the first developed infiltration of lung tissue in individuals who do not have specific immunity. It is diagnosed mainly in childhood and adolescence; it occurs less often in older and elderly people who have suffered a primary infection in the past that ended in a complete cure. Primary form can take the form of:
- primary tuberculosis complex
- tuberculosis of intrathoracic lymph nodes
- of chronically current tuberculosis.
Secondary form develops with repeated contact with MBT or as a result of reactivation of infection in the primary focus. The main secondary clinical forms are presented:
- focal tuberculosis
- infiltrative tuberculosis
- disseminated tuberculosis
- cavernous (fibrous-cavernous) tuberculosis
- cirrhotic tuberculosis
Coniotuberculosis is distinguished separately (tuberculosis developing against the background of pneumoconiosis), tuberculosis of the upper respiratory tract, trachea, bronchi; tuberculous pleurisy. When MBT patients are released into the environment with sputum, they speak of an open form of pulmonary tuberculosis; in the absence of bacilli release, they speak of a closed form. Periodic bacillus discharge is also possible.
The course of PT is characterized by a sequential change of phases of development:
- infiltrative
- decay and insemination
- resorption of the hearth
- seals and calcifications.
Symptoms of pulmonary tuberculosis
Primary tuberculosis complex
The primary tuberculosis complex combines the signs of specific inflammation in the lung and regional bronchoadenitis. It can occur asymptomatically or under the guise of colds, therefore, mass screenings of children (Mantoux test) and adults (preventive fluorography) contribute to the detection of primary pulmonary tuberculosis.
Subacute occurs more often: the patient is concerned about dry cough, subfebrility, fatigue, sweating. In acute manifestation, the clinic resembles nonspecific pneumonia (high fever, cough, chest pain, shortness of breath). As a result of treatment, resorption or calcification of PTC (the focus of the Rut) occurs. In adverse cases, it can be complicated by caseous pneumonia, cavern formation, tuberculous pleurisy, miliary tuberculosis, dissemination of mycobacteria with damage to the kidneys, bones, meninges.
Tuberculosis of the intrathoracic lymph nodes
In tuberculosis, the symptoms are caused by compression of the large bronchi and mediastinal organs by enlarged lymph nodes. This form is characterized by a dry cough (whooping cough, bitonal), an increase in cervical and axillary nodes. Young children often have difficulty exhaling – expiratory stridor. The temperature is subfebrile, febrile “candles” may occur.
Signs of tuberculosis intoxication include lack of appetite, weight loss, fatigue, pale skin, dark circles under the eyes. Venous congestion in the thoracic cavity may be indicated by the expansion of the venous network on the skin of the chest. This form is often complicated by endobronchial tuberculosis, segmental or lobular lung atelectasis, chronic pneumonia, exudative pleurisy. With the breakthrough of caseous masses from the lymph nodes through the bronchial wall, pulmonary foci of tuberculosis can form.
Focal pulmonary tuberculosis
The clinical picture of focal tuberculosis is asymptomatic. Cough is absent or occurs rarely, sometimes accompanied by the release of scanty sputum, pain in the side. In rare cases, hemoptysis is noted. More often, patients pay attention to the symptoms of intoxication: unstable subfebrility, malaise, apathy, decreased performance. Depending on the prescription of the tuberculosis process, fresh and chronic focal pulmonary tuberculosis are distinguished.
The course of focal pulmonary tuberculosis is relatively benign. In patients with impaired immune reactivity, the disease can progress into destructive forms of pulmonary tuberculosis.
Infiltrative pulmonary tuberculosis
The clinical picture of infiltrative pulmonary tuberculosis depends on the size of the infiltrate and can vary from mild symptoms to an acute febrile condition resembling influenza or pneumonia. In the latter case, there is a pronounced high body temperature, chills, night sweats, general weakness. On the part of the respiratory system, cough with sputum and streaks of blood worries.
The pleura is often involved in the inflammatory process in the infiltrative form of pulmonary tuberculosis, which causes the appearance of pain in the side, pleural effusion, lagging of the affected half of the chest when breathing. Complications of infiltrative pulmonary tuberculosis can be caseous pneumonia, lung atelectasis, pulmonary hemorrhage, etc.
Disseminated pulmonary tuberculosis
It can manifest in acute (miliary), subacute and chronic forms. Typhoid form of miliary pulmonary tuberculosis is characterized by the predominance of intoxication syndrome over bronchopulmonary symptoms. It begins acutely, with an increase in temperature to 39-40 ° C, headache, dyspeptic disorders, sharp weakness, tachycardia. With increased toxicosis, a violation of consciousness, delirium may occur.
In the pulmonary form of miliary pulmonary tuberculosis, respiratory disorders are more pronounced from the very beginning, including dry cough, shortness of breath, cyanosis. In severe cases, acute cardiopulmonary insufficiency develops. The meningeal form corresponds to the symptoms of damage to the meninges.
The subacute course of disseminated pulmonary tuberculosis is accompanied by moderate weakness, decreased performance, decreased appetite, weight loss. Occasional temperature rises occur. The cough is productive, does not bother the patient much. Sometimes the first sign of the disease is pulmonary bleeding.
Chronic disseminated pulmonary tuberculosis in the absence of exacerbation is asymptomatic. During the outbreak of the process, the clinical picture is close to the subacute form. Disseminated pulmonary tuberculosis is dangerous for the development of extrapulmonary tuberculosis, spontaneous pneumothorax, severe pulmonary bleeding, amyloidosis of internal organs.
Cavernous and fibrous-cavernous pulmonary tuberculosis
The nature of the course of the cavernous tuberculous process is undulating. In the decay phase, intoxication symptoms, hyperthermia increase, cough increases and the amount of sputum increases, hemoptysis occurs. Bronchial tuberculosis and nonspecific bronchitis are often associated.
Fibrous-cavernous pulmonary tuberculosis is characterized by the formation of cavities with a pronounced fibrous layer and fibrous changes in the lung tissue around the cavity. It proceeds for a long time, with periodic exacerbations of general infectious symptoms. With frequent outbreaks, respiratory failure of the II-III degree develops.
Complications associated with the destruction of lung tissue are profuse pulmonary bleeding, bronchopleural fistula, purulent pleurisy. The progression of cavernous pulmonary tuberculosis is accompanied by endocrine disorders, cachexia, renal amyloidosis, tuberculous meningitis, cardiopulmonary insufficiency – in this case, the prognosis becomes unfavorable.
Cirrhotic pulmonary tuberculosis
It is the outcome of various forms of pulmonary tuberculosis with incomplete involution of a specific process and the development of fibrotic-sclerotic changes in its place. With pneumocyrrhosis, the bronchi are deformed, the lung is sharply reduced in size, the pleura is thickened and often calcified.
Changes occurring in cirrhotic pulmonary tuberculosis cause the leading symptoms: severe shortness of breath, pulling chest pain, cough with purulent sputum, hemoptysis. With exacerbation, signs of tuberculosis intoxication and bacillus discharge will join. A characteristic external sign of pneumocyrrosis is the flattening of the chest on the side of the lesion, narrowing and retraction of the intercostal spaces. With a progressive course, the pulmonary heart gradually develops. Cirrhotic changes in the lungs are irreversible.
Pulmonary tuberculosis
It is an encapsulated caseous focus formed at the end of an infiltrative, focal or disseminated process. With a stable course, symptoms do not occur, the formation is detected by X-ray of the lungs accidentally. In the case of progressive pulmonary tuberculosis, intoxication increases, subfebrility appears, chest pain, cough with sputum separation, hemoptysis is possible. With the disintegration of the tuberculoma focus, it can transform into cavernous or fibrous-cavernous pulmonary tuberculosis. Less often there is a regressive course of tuberculoma.
Diagnostics
The diagnosis of a particular form of PT is made by a phthisiologist on the basis of a combination of clinical, radiation, laboratory and immunological data. For the recognition of secondary tuberculosis, a detailed history collection is of great importance. To confirm the diagnosis is carried out:
- Radiation diagnostics. Lung x-ray is a mandatory diagnostic procedure that allows you to identify the nature of changes in the lung tissue (infiltrative, focal, cavernous, disseminated, etc.), to determine the localization and prevalence of the pathological process. The detection of calcified foci indicates a previously transferred tuberculosis process and requires clarification of data using CT or MRI of the lungs.
- Analyzes. Detection of MBT is achieved by repeated examination of sputum (including PCR), bronchial flushing waters, pleural exudate. But the fact of the absence of bacillus excretion in itself is not a reason to exclude PT. Modern immunological tests can detect tuberculosis infection with almost 100% probability. These include QuantiFERON and T-spot. TB.
- Tuberculin diagnostics. Methods of tuberculin diagnostics include the diaskin test, Pirke and Mantoux tests, but these methods themselves can give false results. Sometimes, to confirm pulmonary tuberculosis, it is necessary to resort to trial treatment with anti-tuberculosis drugs with an assessment of the dynamics of the X-ray picture.
According to the results of the diagnosis, pulmonary tuberculosis is differentiated with pneumonia, lung sarcoidosis, peripheral lung cancer, benign and metastatic tumors, pneumomycosis, lung cysts, abscess, silicosis, lung and vascular abnormalities. Additional diagnostic search methods may include bronchoscopy, pleural puncture, lung biopsy.
Treatment of pulmonary tuberculosis
In phthisiological practice, a comprehensive approach to the treatment of pulmonary tuberculosis has been formed, including drug therapy, if necessary, surgical intervention and rehabilitation measures. Treatment is carried out in stages: first in a tube station, then in sanatoriums and, finally, on an outpatient basis. Regime moments require the organization of therapeutic nutrition, physical and emotional rest.
- Anti-tuberculosis therapy. The leading role is given to specific chemotherapy with the help of drugs with antitubercular activity. For the treatment of various forms of pulmonary tuberculosis, 3-, 4- and 5-component schemes have been developed and applied (depending on the number of drugs used). First-line tuberculostatics (mandatory) include isoniazid and its derivatives, pyrazinamide, streptomycin, rifampicin, ethambutol; second-line agents (additional) are aminoglycosides, fluoroquinolones, cycloserine, ethionamide, etc. The methods of administration of drugs are different: orally, intramuscularly, intravenously, endobronchially, intrapleural, inhalation. Courses of anti-tuberculosis therapy are carried out for a long time (on average 1 year or longer).
- Pathogenetic therapy. In case of pulmonary tuberculosis, it includes taking anti-inflammatory drugs, vitamins, hepatoprotectors, infusion therapy, etc. In the case of drug resistance, intolerance to anti-tuberculosis drugs, with pulmonary bleeding, collapse therapy is used.
- Surgical treatment. With appropriate indications (destructive forms of pulmonary tuberculosis, empyema, cirrhosis, etc.), various surgical interventions are used: cavernotomy, thoracoplasty, pleurectomy, lung resection.
Prevention
Prevention of pulmonary tuberculosis is the most important social problem and a priority state task. The first step on this path is mandatory vaccination of newborns, children and adolescents. During mass examinations in preschool and school institutions, intradermal tuberculin Mantoux tests are used. Screening of the adult population is carried out by preventive fluorography.
Literature
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- Diagnostic associations between pleural and pulmonary tuberculosis. Qiu L, Teeter LD, Liu Z, Ma X, Musser JM, Graviss EA. J Infect. 2006 Dec;53(6):377-86. link
- Pleuritis as a manifestation of reactivation tuberculosis. Antoniskis D, Amin K, Barnes PF. Am J Med. 1990 Oct;89(4):447-50. link
- Chest Tuberculosis in Children. Naranje P, Bhalla AS, Sherwani P. Indian J Pediatr. 2019 May;86(5):448-458. link
- Intestinal tuberculosis in an HIV-infected patient with advanced immunosuppression. Kawazoe A, Nagata N. Clin Gastroenterol Hepatol. 2012 Sep;10(9):A24 link