Middle lobe syndrome is a variety of pathological processes that lead to stenosis of the middle lobe of the bronchus and secondary changes in the lung tissue of the middle lobe of the right lung. Pathology may be asymptomatic or accompanied by subfebrility, cough with a small amount of sputum, hemoptysis, chest pain on the affected side. X-ray data and endoscopic picture are crucial in the diagnosis of the middle lobe syndrome. Depending on the cause of the middle-pain syndrome and the nature of the change in the pulmonary parenchyma, conservative or surgical treatment can be carried out.
Middle lobe syndrome (MLS) is a term used in practical pulmonology to denote a number of pathological conditions accompanied by atelectasis and a decrease in the volume of the middle lobe of the right lung. According to various authors, srednedolevoy syndrome occurs in 0.33-6% of lung patients, about 2 times more often it is found in men. MLS is a preliminary clinical and radiological diagnosis that requires further clarification of the causes of this pathological process. Some pulmonologists propose to exclude from this concept cases of atelectasis caused by tumor obturation of the medial bronchus. Meanwhile, in practice, before differential diagnosis and determination of the etiology of changes in the mean lobe, this term may hide, including bronchogenic cancer.
Causes of middle lobe syndrome
The isolation of this syndrome is due to the relatively high frequency of damage to this area of the right lung, which in turn is associated with the anatomical features of the middle lobe. Compared with other lobar bronchi, the medial bronchus has the narrowest diameter and the longest length, in addition, when moving away from the intermediate bronchus, it forms an acute angle (approximately 30 °). Also, in the immediate vicinity of the medial bronchus, there is a large number of bronchopulmonary lymph nodes, with hyperplasia of which its compression occurs from the outside. In view of these features, the violation of pulmonary ventilation and bronchial patency occurs most easily in the middle lobe.
The immediate causes leading to the appearance of the MLS can be acute or chronic pneumonia, lung abscess, deforming bronchitis, bronchiectasis, broncholithiasis, bronchial foreign body, tuberculosis, lung sarcoidosis, lymphogranulomatosis, etc. The mechanism of development of MLS is due to hypoventilation of a portion of the lung tissue, followed by the addition of a sluggish infectious process. Narrowing of the lumen of the medial bronchus caused by compression or inflammatory edema contributes to partial or complete atelectasis of the lobe.
Middle lobe syndrome symptoms
The clinical picture depends on the nature of pathological changes in the middle lobe. The latter can be represented by bronchiectasis, obstructive pneumonitis, pneumosclerosis and cirrhosis, fibroatelectasis or purulent-destructive processes.
In the presence of bronchiectasis, the MLS proceeds in the form of purulent bronchitis. During periods of exacerbations, body temperature rises, cough increases, the amount of purulent sputum increases, sometimes hemoptysis is noted. During the overview lung x-ray, the strengthening and deformation of the pulmonary pattern is determined, areas of emphysema are detected in the lower parts of the lung. During bronchography, baggy or mixed bronchiectasis are detected.
The clinic of the middle-pain syndrome, which proceeds by the type of obstructive pneumonitis, resembles that of pneumonia: fever, severe sweating, headache and muscle pain, tachypnea, cough with reddish sputum, pronounced weakness. For the purposes of differential diagnosis, it is necessary to perform tomograms and determine the cause of the middle lobe syndrome. In this case, most often it turns out to be bronchiolitis or a foreign body of the bronchus.
Pneumosclerosis and cirrhosis of the middle lobe are usually the outcome of previously suffered pneumonia or tuberculosis. This form of the middle lobe syndrome is more common in elderly patients. The clinic is variable; most of the patients are concerned about chest pain, cough with a small amount of sputum, periodic subfebrility. On radiographs, the average fraction is significantly reduced in volume and is determined as an inhomogeneous darkening.
Fibroatelectasis, as a type of mid-lobe syndrome, is quite rare. Usually the diagnosis is made on the basis of radiological data. A characteristic feature is a symptom of “amputation” of the medial bronchus, clearly distinguishable on bronchograms.
Purulent-destructive processes in the middle lobe of the right lung can be represented by chronic pneumonia or chronic abscess. The course of this form of the middle lobe syndrome is accompanied by hyperthermia, chills, cough with purulent, sometimes fetid sputum, inflammatory changes in the blood. Radiologically, one or more cavities are determined against the background of inhomogeneous dimming of the lobe.
A decisive role in the diagnosis of the middle lobe syndrome is assigned to X-ray examinations (radiography in 2 projections, MRI of the lungs, bronchography, CT of the lungs) and bronchoscopy. The radiological criterion is a decrease in the volume of the middle lobe – it is defined as a strip 2-3 cm wide, stretching from the root of the lung to the costal-diaphragmatic sinus. During bronchoscopy, it is possible to identify the cause of the violation of bronchial patency (intra-bronchial obstruction or compression from the outside), detect a mucopurulent or purulent secret at the mouth of the middle lobe bronchus, perform a biopsy and obtain histological confirmation of the presumed diagnosis.
Various variants of the middle lobe syndrome should be differentiated from central lung cancer, tuberculosis, interlobular pleurisy. Less often there is a need to exclude a coelomic cyst of the pericardium and an abdominal-mediastinal lipoma.
Middle lobe syndrome treatment
Conservative treatment of the middle lobe syndrome is possible in the case of clinically insignificant changes, as well as in elderly patients or in the presence of severe concomitant pathology. In such situations, during periods of exacerbation, antibiotic therapy, therapeutic bronchoscopy or rehabilitation of the tracheobronchial tree through a tracheostomy, medicinal inhalations, chest massage are performed.
With frequent exacerbations, ineffectiveness of repeated conservative therapy and pronounced changes in the middle lobe (cirrhosis, destructive processes, etc.), the question of surgical treatment is raised. The scope of surgery depends on the nature of the lesion and can vary from precision resection and lobectomy to pneumonectomy. Prevention of the middle lobe syndrome consists in the prevention and timely treatment of the primary disease.
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