Mediastinal emphysema

Introduction to mediastinal emphysema Mediastinalemphysema refers to the accumulation of air into the connective tissue space in the mediastinal pleura for various reasons. It can be spontaneous, chest trauma, perforation of the esophagus, iatrogenic factors, etc. The disease is more common in newborns and infants, and the incidence of the disease ranges from 0.04% to 1%. Adults are not uncommon. Adult males have more outbreaks than females. basic knowledge The proportion of illness: 0.001% Susceptible people: no specific population Mode of infection: non-infectious Complications: pneumothorax

Cause of mediastinal emphysema

Alveolar wall rupture (35%):

The alveolar wall is caused by a sharp rise in the alveolar pressure or damage due to other diseases, which can cause the gas to enter the interstitial lung space from the alveoli, forming interstitial emphysema; the gas then enters the mediastinum along the sheath around the pulmonary blood vessels, often because There is visceral pleural injury combined with spontaneous pneumothorax, but it can also be seen that only mediastinal emphysema, common causes such as forced cough or inhalation after forced breath, caused by a rapid increase in alveolar pressure, acute airflow in acute asthma caused by alveolar A sudden increase in internal pressure (especially in children), improper use of mechanical ventilation caused by high airway pressure, excessive intrathoracic pressure during tension pneumothorax can also cause alveolar pressure in adjacent lung tissue to cause alveolar rupture, golden yellow grapes The alveolar wall is damaged by diseases such as cocci pneumonia, and the alveolar wall damage caused by external shear force in closed chest trauma.

Airway rupture (20%):

Most common in patients with chest trauma, there are also reports of a few tracheal tumors complicated with mediastinal emphysema; fiberoptic bronchoscopy may cause mediastinal emphysema due to cough in the patient during operation or rupture of the alveolar wall for hernia, or due to biopsy Damage to the airway wall allows gas to break into the mediastinum from the airway.

Esophageal rupture (20%):

Including severe vomiting caused by esophageal rupture, esophageal trauma, endoscopic examination of the esophagus, esophageal fistula obstruction and proximal rupture, foreign body injury esophagus, esophageal cancer tumor tissue necrosis, esophageal surgery and so on.

Surgical factors (10%):

For example, after tracheotomy, after thyroid surgery, after tonsillectomy, air from the neck wound into the subcutaneous tissue accumulation, along the deep fascia of the neck can enter the mediastinum. And the intra-abdominal gas after artificial pneumoperitoneum can enter the mediastinum along the diaphragmatic aortic rupture and the loose connective tissue around the esophageal hiatus.

Mediastinal emphysema prevention

Active treatment of the primary disease. Prevent severe vomiting and cause esophageal rupture, esophageal trauma, etc., do a variety of checks when the action is gentle, to avoid damage to the esophagus, airways and other tissues.

Mediastinal emphysema complications Complications

Combined pneumothorax: gas enters the pleural cavity, causing a state of accumulation of gas, called pneumothorax. It can occur spontaneously, or it can be caused by disease, trauma, surgery or diagnosis, and improper treatment. Gas enters the pleural cavity through the chest wall, diaphragm, mediastinum or visceral pleura.

Mediastinal emphysema symptoms Common symptoms Irritability, heart sounds, distant jugular vein anger, sternal pain, subcutaneous emphysema, dyspnea, chest tightness, sputum, blood pressure, decreased jugular vein filling

The symptoms of mediastinal emphysema vary in severity, mainly related to the rate of mediastinal emphysema, the amount of mediastinal gas, whether it is associated with tension pneumothorax, etc., a small amount of gas accumulation patients can be completely asymptomatic, only on the chest X-ray film see the mediastinum The signs of emphysema, more gas, when the pressure is higher, the patient can feel chest discomfort, pharyngeal obstruction, post-sternal pain and radiation to the shoulders and upper limbs on both sides, a large amount of gas in the mediastinum or combined with tension pneumothorax The clinical manifestations are critical, severe breathing difficulties, irritability, confusion, and even coma, and obvious cyanosis. If not rescued in time, it can quickly endanger life.

Physical examination can find subcutaneous emphysema in the neck. In severe cases, subcutaneous emphysema can spread to the face, chest, upper limbs, and even spread to the abdomen and lower limbs, skin mucous membranes, difficulty in breathing, blood pressure in patients with severe disease, pulse frequency, jugular vein anger Zhang, the apex beats can not be touched, the heart sounds narrowed or disappeared, and the heart sounds far away. About half of the patients can smell the Hammer sign in the pre-cardiac area, which is clearer when lying on the left side. Those with tension pneumothorax can still see the corresponding signs.

Examination of mediastinal emphysema

Chest X-ray examination is decisive for the diagnosis of mediastinal emphysema. The posterior pleural pleura is displaced to the sides to form a high-density linear shadow parallel to the mediastinum contour. The translucent shadow of the gas is usually obvious on the left mediastinum and the left edge of the mediastinum. The above signs should be distinguished from the normal translucent band (Mach band) next to the mediastinum. The main point of identification is that there is no high density on the outer side of the Mach band. In the mediastinal pleural shadow, in addition, some patients can still find a gas-permeable bright band beside the thoracic aorta or next to the pulmonary artery. The baby can show the thymus outline when the gas in the mediastinum is more. The mediastinal emphysema appears on the lateral chest radiograph as a posterior sternum. In the widened area of increased brightness, the mediastinal pleura is moved backwards with a linear shadow, and the distance between the heart and the ascending aorta and the sternum is increased. X-ray examination clearly shows the presence of the pneumothorax and the lower neck and Subcutaneous emphysema in the chest.

Chest CT examination: chest CT is not affected by organ overlap, showing clearer mediastinal emphysema, especially when the amount of gas in the mediastinum is less, the posterior anterior chest radiograph is easy to identify.

Diagnosis and diagnosis of mediastinal emphysema

According to the history of the disease associated with mediastinal emphysema, there are symptoms of dyspnea and post-sternal pain, the possibility of mediastinal emphysema should be considered; if there are signs of subcutaneous emphysema in the neck and chest, jugular vein filling, etc., height should be Suspected of this disease, parallel chest X-ray examination to confirm the diagnosis.

Care should be taken to distinguish from other diseases that can cause chest pain, difficulty breathing, cyanosis and other symptoms.

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