From Big Medical Encyclopedia

AVERAGE SHARE SYNDROME — the term accepted for designation of the isolated defeats of an average share of the right lung of various etiology which are characterized by a peculiar radiological symptomatology.

In most cases (apprx. 98%) the syndrome of an average share develops in connection with disturbance of passability of a midlobar bronchial tube at hron. inflammatory processes or owing to a prelum its increased limf, nodes, in particular at tubercular to a bronkhadenita (see). The village of of page does not include the defeats of an average share caused by development of a malignant tumor.

Emergence of the isolated defeats of an average share of the right lung is connected with its anatomo-physiological features: rather small diameter of a midlobar bronchial tube (see. Bronchial tubes ), a peculiar arrangement numerous limf, nodes around its mouth, rather small airfilling of a parenchyma of a share. Difficulties at the expectoration of contents or foreign bodys which are in a midlobar bronchial tube are explained by these features and the frequency of disturbances of ventilating and drainage function of this bronchial tube.

Pathomorphologically S. of page is shown by a pneumonitis (see. Pneumonitis ), the characterized combination of atelectatic, exudative and proliferative, destructive, inflammatory and cicatricial processes; at the same time defeat of intersticial fabric prevails.

Fig. 1. Roentgenograms of a thorax in a straight line(s) and right side projections at a syndrome of an average share: the shadow of the struck average share is specified by an arrow.

Rentgenol. a research — the main way of recognition and differential diagnosis of the isolated defeats of an average share of a lung. At S. on the roentgenogram of a thorax in a direct projection to the right of the IV edge and in front to a diaphragm irregular shape blackout with well designated upper bound usually is located with of page (fig. 1, a). On the side roentgenogram the shadow of the struck share usually has triangular shape. Its borders are formed by interlobar cracks; the top of a shadow is directed to a root of a lung, and its basis — to a front chest wall (fig. 1, b). In the presence bronchiectasias (see) or cavities of disintegration in pulmonary fabric (see. Lungs ) the structure of blackout is heterogeneous, at cirrhotic changes its form comes nearer to wedge-shaped or tape-like. In an exudative and infiltrative phase of inflammatory process, including and a tubercular etiology, the shadow of the struck share usually keeps homogeneous character and the correct triangular shape. Tomography (see) better, than usual rentgenol. the research, allows to establish a form of a shadow, to define features of its contours and structure patol. center. Layer-by-layer rentgenol. a research most informatively in the presence of increased limf, nodes, sites of destruction, bronchiectasias, obturation of a midlobar bronchial tube.

For identification patol. changes in a bronchial tree at S. of page use preferential bronchography (see). Results of a tomography and bronchography in most cases allow to differentiate various chronic inflammatory changes in an average share: bronchiectasias, exacerbations of a pneumonitis, fibroatelektaz, chronic pneumonia.

Fig. 2. A right-hand bronkhogramma at a syndrome of an average share (a side projection): bronchial tubes of an average share (are specified by an arrow) are pulled together, deformed, cylindrical are expanded but to type of bronchiectasias.

The village of of page, caused separately by the developing chronic inflammatory process in an average share, has the following differential diagnostic characters: heterogeneous, cellular character of the shadow having triangular shape, shift and deformation of bronchial branches as chronic deforming bronchitis (see) and bronchiectasias (fig. 2). On the basis of these signs it can be distinguished from cancer of a lung. The stenosis of a midlobar bronchial tube of inflammatory character revealed by means of the directed bronchography, as a rule, is located at distance of 15 — 20 mm from the beginning of a bronchial tube; it distinguishes it from the stenosis caused by bronchogenic cancer, to-ry is located almost at the basis of a midlobar bronchial tube. At bronchogenic cancer also tuberosity, roughness of contours of intermediate and nizhnedolevy bronchial tubes are noted that is confirmed by results of a bronkhoskopiya. Bronkhoskopiya (see) it is necessary to carry out at suspicion of cancer of a midlobar bronchial tube. The last occurs approximately at 3% of all patients with cancer of a lung and at 17 — 18% of persons with the isolated defeat of an average share.

In differential diagnosis of defeats of an average share and the sacculated interlobar pleurisy these bronchographies have crucial importance: at sacculated pleurisy (see) are contrasted, as a rule, not changed midlobar bronchial tube with its segmented branches. Besides, on tomograms the shadow at interlobar pleurisy has homogeneous character while at acute or prolonged pneumonia (see) on tomograms in a side projection gleams of bronchial branchings are visible.

The diagnosis of tuberculosis of an average share of a lung (see. Tuberculosis of a respiratory organs ) it can be reasonable radiological only when in a parenchyma of a share focal shadows are found, and in adjacent departments of a lung — signs of dissimination of process.

In all diagnostically not clear cases the bronkhoskopiya with a biopsy is shown.

Treatment and forecast the isolated defeat of an average share of a lung are defined by the disease which caused them.

Bibliography: Bessonova G. S. Clinicoradiological features of midlobar and lingular damages of lungs, Doctor, business, No. 10, page 76, 1971; Itkina R. E. Syndrome of an average share, Probl. tube., No. 11, page 47, 1969; V. I. and Kipriyanov N. V. Boxes. About differential diagnosis of the central cancer and inflammatory defeats of an average share of the right lung, Vopr. onkol., t. 16, No. 5, page 3,1970; L and N d e N-braten of JI. And Naumov L. B. Radiological syndromes and diagnosis of pulmonary diseases, M., 1972; Rosen-shtraukh L. S., Rybakova N. I. and M. G Vanner. Radiodiagnosis of diseases of a respiratory organs, M., 1978; Sh e x t of e r A. I. Materials for studying of the isolated defeats of an average share of the right lung, Vestn. rentgenol. and radio-gramophones., No. 2, page 34, 1963.

A. I. Shekhter.