Hematogenous disseminated pulmonary tuberculosis in children

Currently, due to the increased resistance of the human body to tuberculosis, the widespread use of specific vaccination and BCG revaccination, and timely diagnosis of primary tuberculosis infection in childhood and adolescence, hematogenous disseminated tuberculosis is rare.

In this form of tuberculosis, a large number of tuberculosis foci of hematogenous origin appear in various organs and tissues. Symmetry of focal changes in the lungs, absence of cavities in the lung tissue for a long time and a high frequency (compared to other forms) of extrapulmonary localizations of tuberculosis are characteristic. The development of disseminated forms of tuberculosis is preceded by a period of primary tuberculosis infection and a breakthrough of the tuberculosis focus into the bloodstream with simultaneous sensitization of the vascular system. For the development of the disease, a decrease in immunity under the influence of unfavorable effects (insolation, malnutrition, intercurrent infections during the turn, etc.) is important. The source of bacteremia in primary tuberculosis is, as a rule, the intrathoracic lymph nodes, from which MBT through the thoracic lymphatic duct enters the jugular vein, the right parts of the heart, the pulmonary and then the systemic circulation. A.I. Abrikosov called this path lymphohematogenous. If MBT enter the systemic circulation, conditions are created for the emergence of generalization of the process with the formation of multiple tuberculous tubercles in almost all organs and tissues. In young children, the disease often occurs in the form of general miliary tuberculosis, when other organs are affected along with the lungs. The source of dissemination in secondary forms of tuberculosis can be the lungs, bones, kidneys and other organs.

According to the prevalence of clinical symptoms and the course of the disease, acute, subacute and chronic forms of disseminated tuberculosis are distinguished. Acute forms include disseminated tuberculosis and acute tuberculous sepsis or Landouzi's typhobacillosis.

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Tuberculous sepsis

Tuberculous sepsis (typhoid form) begins acutely, with high body temperature, dyspeptic disorders, proceeds rapidly, sometimes lightning fast, and within 10-20 days ends fatally, with general intoxication coming to the fore. In the event of death of the patient, small foci of necrosis with a large number of mycobacteria in them are found in all organs.

Acute dissemination is characterized by seeding of all organs with small, millet-like tubercles of the same shape and anatomical structure. Histologically, fresh foci are predominantly lobular-pneumonic in nature with caseous changes. Older productive tubercles consist of lymphoid, epithelioid and giant cells, mostly with necrosis in the center.

Symptoms of hematogenous disseminated tuberculosis in children

The disease begins suddenly, the body temperature immediately rises to 39-40 "C. Sleep is disturbed, appetite disappears, dyspeptic disorders are possible. A dry cough appears, sometimes in the form of attacks. One of the most constant and most painful symptoms for the patient is pronounced shortness of breath. Breathing is shallow, up to 50-70 per minute. The face is pale, cyanosis is clearly expressed, especially the lips and cheeks. The discrepancy between shortness of breath and cyanosis, on the one hand, and the absence of objective changes in the lungs, on the other, should always arouse suspicion of acute disseminated tuberculosis. The general condition of the child is severe, the pulse is rapid, delirium and clouding of consciousness are possible. The state of nutrition and turgor in children are significantly reduced, peripheral lymphadenitis is revealed, a slightly enlarged liver and spleen are palpated. Sometimes roseolous rashes appear on the skin.

Diagnosis of hematogenous disseminated tuberculosis in children

The lungs reveal a box percussion sound, slightly weakened or harsh breathing, and a large number of small, moist, subcrepitating rales, which are best heard in the paravertebral areas. MVT is not detected in sputum. Tuberculin tests are often negative. The anamnesis often contains indications of contact with patients with tuberculosis. The true nature of the disease, if an X-ray examination has not been performed, becomes clear after the appearance of meningeal symptoms or is established only during an autopsy. When the process spreads to the meningeal membranes (meningeal form), symptoms characteristic of serous meningitis come to the fore. Therefore, a diagnostic spinal puncture should be performed according to expanded indications.

In radiographic examination, acute disseminated forms of tuberculosis can be divided into groups depending on the size of the tuberculous foci. In addition to miliary, there are medium- and large-focal forms, and sometimes mixed acute disseminations with uneven sizes of tuberculous foci are detected. Large-focal and mixed disseminations in acute cases are manifestations of complicated forms of primary tuberculosis. They often have complex mechanisms of formation involving lymphohematogenous and bronchogenic routes of spread. The latter are more often encountered in disseminations of subacute or chronic course. In radiographic examination, an increase in the pulmonary pattern and additional shadows of inflammatory-altered interstitial tissue are first detected, then total dissemination along the blood vessels. Their size, as a rule, is no more than 2-3 mm or even less. They are figuratively compared to semolina or a pinhead. The greatest density of foci is determined in the lower and middle sections of the lungs. An important sign is the depletion of the pulmonary pattern with the possible manifestation of fine mesh elements. Only large trunks of the pulmonary pattern near the roots are traced in the form of limited fragments regardless of the size of the foci. The roots of the lungs in young children, as a rule, are expanded on one or both sides, their outer contours are blurred, the structure is reduced, and in adolescents the roots are unchanged or contain calcifications. Fibrosis is determined in the lungs, calcified foci in the apices.

The following signs are characteristic of chronic disseminated tuberculosis:

• symmetrical damage predominantly to the upper parts of the lungs;
• predominantly corticopleural and dorsal localization of changes:
• tendency towards productive nature of lesions;
• development of fine reticular sclerosis;
• low tendency to form cavities;
• development of emphysema;
• thin-walled symmetrical caverns;
• hypertrophy of the right heart;
• the presence of extrapulmonary localizations of the process.

The diversity of morphological changes also determines the diversity of clinical symptoms. The disease can begin acutely, under the guise of influenza. However, more often the disease creeps up gradually, subjective complaints are not characteristic and are very different. The abundance of complaints is due to various disorders of the autonomic and endocrine systems. Children complain of fatigue, headaches, palpitations, chest pain, lack of appetite and sleep, cough, mostly dry, sometimes with the release of a small amount of sputum. The child is thin, pale, irritable, he always has shortness of breath, which increases with any physical activity. Body temperature is often subfebrile, but can also be febrile. Tuberculin tests are positive, sometimes hyperergic. MBT is detected no more often than in 25% of cases and only periodically. Hemoptysis is rare. In the initial stages of the disease, physical changes in the lungs are very scanty. They increase as the process progresses. Percussion sound is shortened in the upper parts of the lungs and box-like in the lower parts. Breathing is uneven, in places bronchial or harsh, in places weakened. Small moist rales are heard on both sides, and in the case of cavern formation - medium- or large-bubble. Leukocytosis is moderately expressed with a shift in the leukocyte formula to the left, lymphopenia, monocytosis and an increase in ESR. In chronic disseminated tuberculosis, the process acquires features of fibrous-cavernous tuberculosis with an exacerbation in the spring-autumn period and an unfavorable outcome.

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Differential diagnostics

In most cases, the picture of disseminated tuberculosis is quite typical and does not present any particular difficulties for diagnosis. However, in pediatric practice, there are cases when disseminated tuberculosis is very difficult to distinguish from a number of diseases: inflammatory non-specific (focal bronchopneumonia, bronchiolitis, cystic cirrhosis).

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Focal pneumonia

Differential diagnostics of disseminated tuberculosis is carried out primarily with non-specific pneumonia. Tuberculin reactions in patients with pneumonia either remain normergic or become negative. Common focal pneumonia is characterized by a more acute onset, greater severity of the general condition, and sharp expression of intoxication symptoms. Physical examination of the lungs in pneumonia reveals more pronounced auscultatory data (compared to tuberculosis). Changes in the hemogram in non-specific inflammation are characterized by high leukocytosis, a pronounced shift in the leukocyte formula to the left, and a high ESR. Focal changes in one lung indicate more of a non-specific process; in pneumonia, focal changes are located in the middle and lower parts of the lungs, and the apices are usually unchanged. In non-specific pneumonia, the nature of the foci on the radiograph is more or less the same, their size is somewhat larger compared to tuberculosis, the contours are more blurred, they are determined against the background of pronounced interstitial inflammation. In subacute and chronic dissemination, cavitary formations in the lungs are often detected. In uncomplicated pneumonia, focal-like shadows are absorbed, leaving no traces. The radiographic picture in non-specific inflammation is more dynamic (compared to tuberculosis). With timely treatment, focal-like shadows are absorbed in a short time (7-10 days). In pneumonia, the roots of the lungs often expand on both sides along the path of reactive adenitis, their contours are blurred. When examining sputum in patients with subacute and chronic dissemination, MBT can be detected in some cases.

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Bronchiolitis

Bronchiolitis most often occurs with acute respiratory viral infections, but can also be caused by other viruses. Bronchiolitis is a widespread lesion of the smallest bronchi and bronchioles, leading to the development of severe obstruction of the respiratory tract, usually with the development of significant respiratory failure. Bronchiolitis is most often found in children under 2 years of age in the spring and winter months in the form of outbreaks, sporadic cases are recorded throughout the cold season.

Unlike acute disseminated tuberculosis, bronchiolitis is preceded by a respiratory viral infection. The body temperature of children with bronchiolitis often drops to normal after a few days, while in acute dissemination, high fever persists for a long time. Auscultation of the lungs of a child with bronchiolitis reveals abundant fine-bubble and dry wheezing; radiologically, small, sometimes merging, nested areas of infiltration are visible mainly in the root region and below. The pathological anatomical basis for them is created partly by fibrinous-cellular plugs that block the lumen of the bronchioles and cause limited atelectasis, partly by lobular-pneumonic changes that often accompany bronchiolitis. Cellular infiltration of the bronchiolar walls is also possible. Radiological changes and auscultatory data in bronchiolitis are distinguished by pronounced dynamism.

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Cystic fibrosis

Cystic fibrosis is an autosomal recessive disease. It is characterized by cystic degeneration of the pancreas, total damage to the glands of the intestine, respiratory tract and other glands (sweat, lacrimal, salivary, etc.) due to blockage of their excretory ducts with viscous secretion. When conducting differential diagnostics with disseminated tuberculosis, it is necessary to take into account that children with cystic fibrosis begin to get sick from the first months of life. With the pulmonary form of the disease, young children develop a cough, it can be similar to a cough with whooping cough or have a rough metallic tint. Due to the increased viscosity of the bronchial secretion, sputum is difficult to expectorate, due to which the cough often ends in vomiting. A similar nature of the cough is not noted in disseminated forms of tuberculosis. In the lungs, various wet and dry rales are heard, caused by both bronchial obstruction, mucus, pus, and an infectious process. The phenomena of chronic bronchopulmonary pathology are steadily progressing. Dyspnea, cyanosis, symptoms of pulmonary-cardiac insufficiency, thickening of the nail phalanges of the fingers appear. In X-ray examination, in contrast to disseminated forms of tuberculosis, in cystic fibrosis the localization of changes can be different, the process is often diffuse. Most often, the upper lobe of the right lung suffers. The dominant picture of bronchitis in the form of an enhanced and deformed pattern with coarse cellular-linear structures can be a background for the formation of heterogeneous local (focal) changes.

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