Atelectasis

Introduction Atelectasis refers to a decrease in the volume or volume of one or more lung segments or lobes. Due to the absorption of gas in the alveoli, atelectasis is usually accompanied by a decrease in the transmittance of the affected area. The adjacent structures (bronchial, pulmonary vascular, interstitial lung) accumulate in the infertile area, sometimes the alveolar cavity is solidified, and other lung tissues are compensated. Sexual emphysema. Atelectasis can be divided into congenital or acquired acquired two. Congenital atelectasis refers to the absence of gas filling in the alveoli at birth, clinically severe breathing difficulties and cyanosis, and children often die of severe hypoxia after birth.

Cause

The main cause of acute or chronic atelectasis in adults is bronchial obstruction. A common cause is the formation of mucus plugs, tumors, granulomas or foreign bodies in viscous bronchial secretions. Atelectasis can also be caused by stenosis or distortion of the bronchi, or by exogenous compression of the bronchus, such as enlarged lymph nodes, tumors or hemangiomas, or exogenous compression of lung tissue such as fluids and gases (such as pleural effusions and pneumothorax). . The surfactant is a mixture of phospholipids, which covers the surface of the alveoli and has the effect of reducing surface tension and maintaining alveolar stability. The damage of alveolar cells that produce surfactants, the exudation of plasma proteins, the presence of inflammatory mediators, and the dispersion of polymeric fibrin with surfactants (as seen in the formation of transparent films) can affect the production and action of surfactants. These factors contribute to atelectasis in the presence of oxygen poisoning, pulmonary edema, adult and neonatal respiratory distress syndrome, pulmonary embolism, general anesthesia or mechanical ventilation.

Acute large-area atelectasis is often a postoperative complication that occurs in upper abdominal surgery, lung resection, and cardiopulmonary bypass (related to hypothermia and intravenous cardioplegia-induced endothelial cell damage). High-dose opioids or sedatives, as well as high-concentration oxygen inhalation during anesthesia, dressing tightness, abdominal distension and physical inactivity, restricting thoracic respiratory activity, squatting, accumulation of bronchial thick secretions, and inhibition of cough reflexes are also beneficial Atelectasis occurs. Central nervous system depression, thoracic abnormalities, pain and muscle spasms and neuromuscular diseases can cause respiratory depression, which affects coughing and sputum, leading to atelectasis. Hyperosmotic blood in diabetic ketoacidosis is also a causative factor, which may be associated with increased viscosity of airway secretions, leading to mucus caulking.

Middle lobe syndrome is a type of chronic atelectasis, often caused by peripheral lymph node compression or endobronchial obstruction. Acute pneumonia can occur and the regression is slow and incomplete, but the bronchoscopy of the middle lobe syndrome can be found without abnormalities. The cause of atelectasis can be explained by the narrowing of the right middle lobes and the failure of collateral ventilation. Partial bronchial obstruction with infection leads to chronic atelectasis and poor drainage of the secretions, eventually leading to chronic lung inflammation.

an examination

Related inspection

Lung ventilation imaging lung and pleural auscultation lung perfusion imaging lung and pleural palpation respiratory mobility

The diagnosis of atelectasis mainly depends on chest imaging examination, etiology, and diagnosis needs to be combined with medical history. X-ray findings of atelectasis are divided into direct X-ray signs and indirect X-ray signs.

1. The direct X-ray signs of atelectasis are: the density of the lung tissue is reduced, the uniformity density is increased, and the density may be uneven during the recovery period or accompanied by bronchiectasis (saccular translucent area). Different degrees of volume reduction, sub-segmental and below atelectasis can be reduced due to ventilation of other lateral branches. The segmental atelectasis is generally blunt-triangular, with a broad and pure face facing the pleural pleural surface, the tip pointing to the hilum, and having a fan shape, a triangle shape, a band shape, a circle shape, and the like.

2, indirect X-ray signs of atelectasis: interlobular fissure inferior lung displacement, such as pleural displacement between the right lung transverse lobes, pleural displacement between the oblique lobes on both sides, due to lung volume reduction The bronchial and vascular textures of the lesion area are gathered, and the adjacent lungs are compensatoryly swelled, which means that the vascular texture is sparse, and the lobes of the lungs are displaced, the lungs are moved to the infertile lung lobes, and the hilar shadows are reduced and disappeared. And the dense image of the atelectasis is separated, the mediastinum, heart, and trachea are displaced to the affected side, especially when the whole lung is atelectasis. Sometimes the healthy side of the lung is moved to the affected side, and the mediastinal hernia is present. High, the chest is narrowed, and the intercostal space is narrowed.

Differential diagnosis

Differential diagnosis:

1. Tuberculosis: Tuberculosis: TB tuberculosis is a chronic infectious disease caused by tubercle bacillus, which can affect multiple organs throughout the body, but tuberculosis is the most common. The pathological features of this disease are tuberculous nodules and caseous necrosis, which are easy to form voids. Clinically, there are many chronic processes, and a few can be acutely ill. Often have low fever, fatigue and other systemic symptoms and cough, hemoptysis and other respiratory manifestations.

2, lung cancer: lung cancer is the most common primary malignant tumor of the lung, the vast majority of lung cancer originated from the bronchial mucosa epithelium, it is also known as bronchial lung cancer. In the past 50 years, the incidence and mortality of lung cancer have risen rapidly in countries all over the world, especially in industrialized countries. Among the male patients who died of cancer, lung cancer has ranked first. More than 40 years ago, the majority of patients who underwent surgical treatment for lung diseases in China were tuberculosis, followed by pulmonary purulent infections such as bronchiectasis and lung abscess. There were few cases of lung cancer.

3, pneumonia: pneumonia refers to the end of the airway, alveolar and pulmonary interstitial inflammation. Symptoms: fever, shortness of breath, persistent dry cough, may have unilateral chest pain, chest pain during deep breathing and coughing, a small amount of sputum or a large amount of sputum, may contain bloodshot. Children with pneumonia, symptoms are often not obvious, may have a mild cough or no cough at all. Should pay attention to timely treatment.

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