Diagnosis of tuberculosis of the intrathoracic lymph nodes

Differential diagnostics

Tuberculosis of the intrathoracic lymph nodes must be differentiated from pathological changes in the mediastinum and root of the lungs of non-tubercular etiology. More than 30 radiological diagnoses of this area are described. In general, they can be divided into three main groups:

• tumor-like lesions of mediastinal organs;
• nonspecific adenopathy;
• abnormalities of vessels of the chest.

When conducting differential diagnosis, the X-ray anatomical structure of the mediastinum should be taken into account. Being a part of the thoracic cavity, the mediastinum in front is limited by the back wall of the sternum and the marginal cartilages, behind - by the vertebral column, from the sides - by medial pleura sheets, at the bottom by the diaphragm, and on the top by the aperture of the thorax.

Children with diseases of the anterior and posterior mediastinum are referred for examination to tuberculosis institutions because of suspicion of a specific process in the hilar lymph nodes. Usually these are children from contact with a patient with active tuberculosis or with changes in sensitivity to tuberculin. In favor of infection indicate a turn, hyperergic tuberculin reactions, an increase in the size of the papule by more than 6 mm in the Mantoux sample with 2 TE. In such cases, the radiographically enlarged shadow of the mediastinum is interpreted unambiguously - suspicion of tuberculosis of the intrathoracic lymph nodes. Localization of education in the anterior or posterior mediastinum allows to exclude a specific process in the intrathoracic lymph nodes, which are characterized by location in the central mediastinum.

To volume formations that affect the mediastinum organs and cause difficulties in differential diagnostics with tuberculous bronchitis, children can include the following: hyperplasia of the thymus gland, thymomas, dermoid cysts and teratomas, neurogenous formations, lymphogranulomatosis, lymphatic leukemia. Sarcoma and sarcoidosis. Most often there is a need to distinguish tuberculosis of the intrathoracic lymph nodes from mediastinal forms of systemic lesions, benign and malignant lymphomas (thoracic sarcoidosis, lymphogranulomatosis, lymphocytic leukemia, lymphosarcoma), inflammatory nonspecific adenopathies (reactive and viral).

Hyperplasia of the thymus gland, thymoma. Hyperplasia of the thymus gland is met in infancy and early childhood. The term "thymoma" unites all types of tumors and cysts of the thymus gland. In a significant part of cases, the lesion of the thymus gland proceeds asymptomatically. With the development of the tumor process, clinical manifestations appear - symptoms of pressure on neighboring organs, as well as symptoms of hormonal activity. Radiographically, thymoma is displayed as an enlargement of the mediastinum from one or both sides. Most often it is asymmetric. The preferred location is the upper and middle divisions of the anterior mediastinum. On the roentgenogram, thymoma, as a rule, is traced from the level of the clavicle, fills the retrosternal space and, tapering to the bottom, depending on the size, can extend up to the diaphragm. The shadow is uniform, has a sharp contour, slightly convex towards the lung tissue. When the enlarged lobes are shifted in one direction, the enlarged mediastinum has a bicyclic character. The size and shape of the tumor-shaped transformed thymus glands vary widely. In the literature indicate the possible waviness of the contours and pear-shaped form, as well as the inclusion of calcium salts. This creates a resemblance to hyperplasia of the intrathoracic lymph nodes. The crucial difference in differentiation is the topical diagnosis.

Dermoid cysts and teratomas are also localized in the anterior mediastinum. Dermoid cysts are the vices of embryonic development - the derivatives of ectoderm. Accordingly, they find such elements as skin, hair, sweat and sebaceous glands. In teratomas, the elements of all three embryonic leaves - ecto-, meso- and endoderms (skin with its appendages, muscles, nerve and bone tissue and even elements of separate organs - teeth, jaws, etc.) are found in teratomas. Dermoid cysts and teratomas clinically, as a rule, do not show themselves, they are usually isolated during X-ray examination. The typical localization of teratomas is the middle section of the anterior mediastinum. Dermoid cysts are very slow. Decisive in the diagnosis is the display of inclusions of bone tissue (for example, teeth, jaw fragments, phalanges). In the absence of documented inclusions, the radiologic picture corresponds to a benign tumor.

Neurogenic formations of frequency rank first among all tumors and cysts of the mediastinum. They are met at all ages, including those of newborns. Most often these are neurinomas - benign tumors that develop from the cells of the Schwannian membrane. Malignant neurinomas develop rarely. Clinical symptoms of neurin are uncharacteristic, long-term, asymptomatic. Most often they are detected with a preventive X-ray examination. X-ray:

• on a direct roentgenogram paravertebrally in the rib-vertebral corner, a tumor is revealed which, as a rule, has the shape of an elongated half-oval, with a broad base adjacent to the spine:
• on the side picture, the shadow of the tumor also has a broad base attached to the spine, and convex forward.

The growth rate of neurin may also be different. The structure of the shadow is uniform, the contours are distinct, sometimes unsharpily tuberous. Neurinomas do not pulsate and do not move when the body position changes.

Sarcoidosis. Tuberculosis of the intrathoracic lymph nodes is differentiated from stage I of sarcoidosis. According to modern ideas, sarcoidosis is a chronic disease of an unclear etiology, characterized by the defeat of the lymphatic system, internal organs and skin with the formation of specific granules, surrounded by a layer of hyalinosis. Vnugrigrudnie lymph nodes in sarcoidosis are affected in 100% of cases, and other organs - less often. Sarcoidosis is found in older children and adolescents. Clinical manifestations of sarcoidosis are diverse. In most cases, the disease is asymptomatic, it is detected accidentally - during a fluorographic examination. In 20% of cases, an acute onset is possible, accompanied by Léfgren's syndrome (a rise in body temperature to 38-39 ° C, erythema nodosum, joint pains and intrathoracic adenopathy). Some patients report a subacute onset with body temperature rises to subfebrile digits, dry cough, general weakness, joint pain. A number of features distinguish tuberculosis of the intrathoracic lymph nodes from sarcoidosis. Sarcoidosis is characterized by tuberculin anergy - in 85-90% of cases, tuberculin reactions are negative, while in tubercular bronchoadenitis they are positive. In more than half of the cases, sarcoidosis proceeds secretly, without pronounced clinical manifestations. In the gemogram in sarcoidosis, leuco- and lymphopenia, monocytosis, and eosinophilia are sometimes noted with normal or slightly increased ESR. In the blood serum - an increase in the content of gamma globulins, also increases the concentration of calcium in the blood and urine. The radiological picture of sarcoidosis of the intrathoracic lymph nodes is characterized, with rare exception, by a two-sided symmetrical increase in these and a sharp delineation. The degree of increase is significant, by the type of adenomegaly. Disturbances in the structure are of the same nature, and there are no changes in the lung pattern around the roots. With significant diagnostic difficulties, a biopsy is shown, if possible peripheral lymph nodes, in their absence, mediastinoscopy with biopsy is performed. At histological research sarcoid granulomas differ monomorphism, they have identical sizes, the form, a structure. Granulomas consist of epithelioid cells. Unlike tuberculosis, the centers of granulomas do not have necrosis. In rare cases, there may be giant cells such as Pirogov-Langhans cells. Granulomas are delimited from the surrounding tissue by a band of reticular fibers and hyaline. Typical for tuberculosis the shaft from leukocytes is absent.

Lymphogranulomatosis. Clinico-radiological manifestations of tuberculosis of the intrathoracic lymph nodes are similar to lymphogranulomatosis. Symptoms such as loss of body weight, weakness, body temperature rises to subfebrile and febrile digits, determined by radiographically enlarged hilar lymph nodes, are encountered in both diseases. With lymphogranulomatosis due to the development of the immunological failure syndrome, tuberculin reactions are negative even in those cases when the disease was preceded by a positive sensitivity to tuberculin. Peripheral lymph nodes with lymphogranulomatosis are affected in 90-95% of cases and are determined mainly in cervical and supraclavicular areas. Unlike tuberculosis, they can reach considerable sizes, have a woody density, are not soldered to the surrounding tissue, usually do not undergo purulent fusion. Lymphogranulomatosis is characterized by anemia, leukocytosis with neutrophilia and progressive lymphopenia, eosinophilia. Tuberculosis is not characterized by changes in red blood, leukocytosis is less, lymphocytosis is possible. In the X-ray study of lymphogranulomatosis, lymph node hyperplasia is detected in a tumor-like type, the degree of their increase is significant. The process, as a rule, has a symmetric distribution. The structure of tumor-transformed lymph nodes is uniform. The upper mediastinum appears to be enlarged, with clear polycyclic outlines.

When bronchological examination, usually identify indirect signs of an increase in the intrathoracic lymph nodes, while in tuberculous bronchoadenitis, a specific bronchial pathology and limited catarrhal endobronchitis can be noted. When microscopic research in favor of lymphogranulomatosis speaks polymorphic cell composition: determine neutrophils, lymphocytes, plasma and reticuloendothelial cells, a fairly high percentage of eosinophils. The finding of Berezovsky-Sternberg cells verifies the diagnosis.

Lymphocytic leukemia. Sarcoma. The increase of the intrathoracic lymph nodes with lymphatic leukemia and sarcoma can also simulate the picture of tubercular bronchoadenitis. Unlike tuberculosis, tuberculin reactions are negative. Of great importance is the leukogram. For leukemia is characterized by a sharp increase in the number of lymphocytes, in the smear, in addition to normal lymphocytes, determine their young and pathological forms, blast cells. Clarify the diagnosis of the sternal puncture and the examination of bone marrow obtained by trepanobiopsy. Lymph nodes are enlarged in tumor type. The development of lymphocytic leukemia in childhood and adolescence results, as a rule, in the involvement of all groups of intrathoracic lymph nodes that form large symmetrical conglomerates of a homogeneous structure with clear polycyclic contours. Rapid progression of the disease can cause compression syndrome with violation of bronchial patency and compression of the superior vena cava. Of decisive importance in diagnosis is hematological examination - myelogram, trepanobiopsy. Distinctive recognition of sarcoma from tuberculosis is helped by the symptom of a symmetrical lesion, a significant increase in the intrathoracic lymph nodes, which have a homogeneous structure and rapid growth, which is especially characteristic for children and adolescents.

Nonspecific adenopathy. In some cases, tuberculosis of the intrathoracic lymph nodes should be differentiated from nonspecific diseases accompanied by the syndrome of intrathoracic adenopathy: measles, whooping cough, and viral infections. The need for differential diagnosis often occurs in a child infected with the MBT. In children with nonspecific adenopathies, a history of frequent acute respiratory viral infections and diseases of the ENT organs is usually noted. In the clinical status of the child ascertain the changes in reactivity, proceeding according to the type of allergic syndromes or diathesis. In the X-ray study, the degree of enlargement of the intrathoracic nodes is established more than is characteristic of tuberculosis. The structure of the lymph nodes is uniform. In the acute period, a diffuse enhancement of the pulmonary pattern is noted, due to hyperemia, interstitial edema. Dynamic observation indicates the involution of the process in a relatively short time. Diagnostic tracheobronchoscopy in patients with nonspecific intrathoracic adenopathies usually reveals a bronchial picture of the diffuse nonspecific endobronchitis. Specific adenopathy is complicated by limited processes in the bronchi - tuberculosis at different phases of its development or catarrhal endobronchitis. As a rule, such children often turn to the doctor with complaints identical to tuberculosis intoxication (prolonged subfebrile condition), frequent ARI, dry cough, poor appetite, drowsiness, etc.

[1], [2], [3], [4], [5], [6]