Pneumomediastinum is the presence in the soft tissues of the mediastinum of air or gas coming from the trachea, bronchi, lungs, abdominal cavity, esophagus when they are damaged. It is accompanied by chest pains, shortness of breath, subcutaneous emphysema of the neck, face, chest. A significant amount of air in the mediastinum leads to a violation of cardiac activity. The diagnosis is made on the basis of an examination, X-ray examination or CT of the chest. The small pneumomediastinum is stopped independently, a large or increasing volume of air is surgically removed.
ICD 10
J98.2 P25.2
Meaning
Pneumomediastinum (mediastinal emphysema, mediastinal emphysema) occurs when air enters the mediastinal fiber from the respiratory tract, esophagus and some other organs. In 2-3 out of 1000 newborns, mediastinal emphysema is diagnosed, which is a complication of birth trauma or malformations of the respiratory system. Spontaneous pneumomediastinum is more common in adults than in children. Mostly young people under the age of 30 suffer. Among the cases, 76% are men, 24% are women. Small pneumomediastinum often remains unrecognized due to poorly expressed clinical manifestations.
Pneumomediastinum causes
Mediastinal emphysema easily occurs when the integrity of the wall of a hollow organ is violated or the alveoli are ruptured. The gas penetrates into the mediastinal space due to its close communication with the pulmonary parenchyma, neck tissue, retroperitoneal space. In addition, atmospheric air can come from outside if the chest wall is damaged. All etiological factors can be combined into two large groups:
- Mechanical damage. The most common causes of air accumulation in the mediastinal fiber are injuries to the head and neck, respiratory organs, and digestive tract. Pneumomediastinum occurs with penetrating wounds of the thoracic cavity and when the lungs are injured by rib fragments. Often, barotrauma leads to mediastinal emphysema.
- Endogenous factors. Perforation of hollow organs, which occurs during diverticula, ulcerative and oncological processes, can cause pneumomediastinum. Another common cause is ruptures of the alveoli and air bulls during coughing, straining, vomiting, inhalation of drugs and narcotic drugs.
Pathogenesis
The mechanism of development of mediastinal emphysema is directly dependent on the path of air penetration into soft tissues. When a hollow organ or chest wall is damaged, air enters directly into the mediastinum or moves there through the communicating cellular spaces of the neck, retroperitoneal tissue, holes in the diaphragm. Spontaneous pneumomediastinum develops due to increased pressure inside the alveoli, which leads to rupture of the interalveolar septa and small bronchioles. The pressure difference directs air through the peribronchial space to the root of the lung, mediastinal tissues and spreads further. There is displacement and compression of vital organs, subcutaneous emphysema.
Classification
Pneumomediastinum is conditionally divided into small, asymptomatic or with minor clinical manifestations, and large, contributing to the development of acute heart failure. In thoracic surgery and traumatology, emphysema is classified taking into account etiological factors. The following types of pneumomediastinum are distinguished:
1 Spontaneous. Occurs suddenly for no apparent reason. The provoking factors are sometimes smoking tobacco, marijuana, inhaling cocaine and other narcotic substances. It can develop with straining (during the act of defecation, in childbirth), playing wind instruments.
2 Secondary. It is a complication of injuries and a number of diseases. It is considered secondary when determining the root cause of the disease. It is divided into:
- Traumatic. It develops with injuries of the chest organs, perforation of the walls of the respiratory tract or esophagus by a foreign body. It occurs with wounds of the head, neck, ruptures of the hollow organs of the abdominal cavity and retroperitoneal space.
- Non-traumatic. It is provoked by certain conditions (status asthmaticus, exacerbation of chronic obstructive pulmonary disease), complicates the course of interstitial lung diseases. It appears when an ulcer or a cancerous tumor of the gastrointestinal tract is punctured.
- Iatrogenic. It occurs as a result of injury to the chest wall and respiratory tract during therapeutic and diagnostic measures (tracheostomy, ventilator, lung biopsy and others). The causes of iatrogenic mediastinal emphysema may be the swelling of the esophagus and dental manipulations on the lower jaw.
Artificial (diagnostic) pneumomediastinum is distinguished as a separate form. To contrast the mediastinal organs, oxygen, carbon dioxide, nitrous oxide or atmospheric air is dosed into the mediastinal fiber. It is used for the diagnosis of primary and metastatic tumors of the intra-thoracic lymph nodes, esophagus.
Symptoms of pneumomediastinum
The intensity of pain in mediastinal emphysema is affected by the volume of air entering the mediastinum, the nature of the primary disease or injury. Pain of a stabbing or compressive nature is localized behind the sternum, radiates into the neck, shoulder girdle, occasionally into the abdomen, lower back. Patients often do not attach importance to a weakly expressed pain syndrome with a small spontaneous pneumomediastinum, and the disease can become an accidental finding during a preventive examination.
A significant accumulation of air in the mediastinal fiber causes shortness of breath. A specific sign of pneumomediastinum is subcutaneous emphysema. The neck, the upper half of the chest, and the patient’s face become puffy. Swallowing may be impaired. The voice becomes hoarse or nasal. Sometimes the process spreads to the lower chest and abdomen. With the increasing intake of air into the mediastinal tissues, breathing and heartbeat become more frequent, and blood pressure decreases. The patient assumes a forced sitting position, feels a sense of fear.
Complications
A tense pneumomediastinum, characterized by continuous, rapid intake of air into the mediastinum, significantly worsens the patient’s condition. It leads to compression of the main veins, causes acute circulatory failure. Sometimes pneumopericardium develops, followed by cardiac tamponade. Without urgent medical intervention, death may occur. Air often damages the pleural leaves and causes concomitant one- or two-sided pneumothorax. Complications of the secondary process depend on the underlying disease. Thus, with perforations of the stomach and intestines, pneumomediastinum is often combined with mediastinitis.
Diagnostics
Patients with suspected pneumomediastinum are examined by thoracic surgeons or traumatologists. The survey clarifies the presence of respiratory and oncological diseases, chest bruises, injuries and other factors contributing to the appearance of mediastinal emphysema. Examination reveals swelling of the neck, face. With severe subcutaneous emphysema, the skin acquires a bluish hue, the jugular veins bulge out. To detect gas in the mediastinum , it is used:
- Physical examination. Subcutaneous accumulation of air is indicated by crepitation during palpation of the jugular fossa, neck, supraclavicular areas. Due to mediastinal emphysema, the boundaries of cardiac dullness are not percutorily determined. During auscultation, the heart tones are deaf. It is characterized by the presence of a mediastinal crunch synchronous with heart tones (Hamman’s symptom), which increases in the position on the left side.
- Radiation diagnostics. A mandatory examination method for suspected pneumomediastinum is chest x-ray in two projections. On X-rays, gas bands are determined, the mediastinal pleura is emphasized, the contours of the mediastinum are clearly outlined. The analysis of radiographs in dynamics allows you to identify the increase in emphysema. In unclear cases, CT of the chest is indicated.
When mediastinal emphysema is detected, it is necessary to determine the cause of the appearance of air in mediastinal tissues. According to the indications, fibrobronchoscopy, esophagogastroscopy, X-ray examination of the esophagus with contrast are performed. If the primary disease cannot be diagnosed, pneumomediastinum is regarded as spontaneous.
Pneumomediastinum treatment
Detection of any amount of air in the mediastinal tissues is an indication for hospitalization of a patient in a surgical hospital. A small (up to 2-2.5 liters) pneumomediastinum is independently resolved within a week. Restriction of physical activity and oxygen therapy accelerate recovery. Antibiotics are used to prevent infectious complications. Analgesics and antitussive drugs are prescribed. With a massive accumulation of gas, signs of compression of vital organs, air evacuation is performed surgically. In the area of the jugular sternum, a mediastinotomy is performed, a drainage is installed through which air is aspirated. At the same time, the injury or primary process is being treated.
Prognosis and prevention
The small pneumomediastinum proceeds favorably and ends with a complete recovery. The medical literature describes isolated cases of relapse of the disease. Severe injuries with ruptures of the bronchi, trachea or esophagus usually lead to intense mediastinal emphysema. Without emergency surgery, this condition ends fatally. Primary prevention is reduced to timely detection and treatment of chronic diseases of the respiratory system, digestive organs, injury prevention, accurate medical manipulations. Persons who have suffered mediastinal emphysema are recommended to give up bad habits and avoid excessive physical exertion.