Primary tuberculosis: diagnosis

Since bacteriological diagnosis of primary tuberculosis has objective difficulties, in the case of local forms of primary tuberculosis, an X-ray examination becomes particularly important, the informativeness of which largely depends on the technique and technology. Sometimes, patients with clinical signs of the disease and a bias of sensitivity to tuberculin on the survey radiographs in two projections and on longitudinal tomograms of the chest organs do not detect pathological changes. Mark only a slight expansion of the shadow of the root of the lung, a decrease in its structure, an increase in the basal pulmonary pattern. In this case, tuberculosis intoxication is usually diagnosed, as there is no convincing evidence of a local lesion of the lymph nodes. In a control study at 6-12 months in the root of the lung can detect microcalcinates. This dynamic of the process indicates the tuberculosis of the intrathoracic lymph nodes, which was not recognized in the primary study. The diagnosis of "primary tuberculosis" is established retrospectively.

With the help of CT it is possible to objectively assess the density of lymph nodes and reveal even small changes in their size. It is possible to investigate the intrathoracic lymph nodes of all groups, including bifurcation, retrocaval and para-aortic, which are not visible with conventional radiography, and also distinguish the calcified arterial ligament from calcinate in the intrathoracic lymph node.

With a pronounced form of tuberculosis of the intrathoracic lymph nodes, adenopathy can be detected with conventional radiographic examination. On the roentgenogram in a direct projection, the inflammation of the nodes of the bronchopulmonary and tracheobronchial groups in the early phase is manifested by an increase in the shadow of the lung root in length and width. The outer border of the root becomes convex and blurred, its structure is broken, it is impossible to distinguish the bronchial stem. When paratracheal lymph nodes are affected, an expansion of the median shade with a semicircular or polycyclic margin is observed. With the resolution of perinodular inflammatory changes and dense consistency, the lymph nodes are better visualized and have clear contours. In such cases, the changes revealed by X-ray examination are similar to the tumor lesion pattern.

With a favorable course of uncomplicated bronchoadenitis, the drawing of the lung root can become normal. However, more often the root of the lung is deformed due to fibrotic changes. In some groups of lymph nodes with time kaltsinaty formed on the X-ray patterns inclusions of high intensity with clear contours. CT allows us to see how the lymph nodes impregnate with calcium salts. Large lymph nodes are usually calcined to a greater extent along the periphery, while in the center are visible calcinates in the form of granules. For lymph nodes of a smaller size, a characteristic deposition of calcium salts in different parts is characteristic.

In the x-ray picture of the primary tuberculosis complex, three main stages are conventionally distinguished: pneumonic, resorption and compaction, petrification. These stages correspond to the clinical and morphological patterns of primary tuberculosis.

In the pneumonic stage, a darkening area with a diameter of 2-3 cm or more, irregular shape, with diffuse contours and a heterogeneous structure is found in the pulmonary tissue. The central part of the blackout caused by the primary pulmonary lesion has a higher intensity on the roentgenogram, and the surrounding perifocal infiltration is smaller. On the side of the lesion, also note the expansion and deformation of the shadow of the root of the lung with a blurred outer boundary. Darkening in the lung is associated with the shadow of the dilated root and sometimes completely merges with it. Preventing distinct visualization of the root in the survey image. In the natural course of the process, the duration of the pneumonic stage is 4-6 months.

The stage of resorption and compaction is characterized by the gradual disappearance of perifocal infiltration in the pulmonary tissue and perinodular infiltration in the region of the lung root. The components of the primary complex in the lung, lymph nodes and their lymphangitis binding can be determined more clearly. The pulmonary component is usually represented by a limited darkening or focus of medium intensity, the lymph nodes - by expansion and deformation of the lung root. It is clearly possible to identify the "symptom of bipolarity" of the lesion. In the future, the size of the pulmonary component and the affected lung root continue to decrease; gradually they show signs of calcification. The duration of the resorption and compaction stage is about 6 months.

For the stage of petrification, the formation in the pulmonary tissue of a high intensity focal shadow with sharp contours (the Gon focus) and inclusions of high density (calcinates) in the regional lymph nodes.

[1], [2], [3], [4],