Pneumothorax is the accumulation of gas in the pleural cavity, leading to the collapse of lung tissue, displacement of the mediastinum to the healthy side, compression of the mediastinal blood vessels, lowering of the diaphragm dome, which ultimately causes a disorder of respiratory function and blood circulation. With disease, air can penetrate between the leaves of the visceral and parietal pleura through any defect on the surface of the lung or in the chest. The air penetrating into the pleural cavity causes an increase in intrapleural pressure (normally it is lower than atmospheric pressure) and leads to the collapse of part or the whole lung (partial or complete collapse of the lung).
Causes of pneumothorax
The mechanism of development of pneumothorax is based on two groups of causes:
1. Mechanical damage to the chest or lungs:
- closed chest injuries accompanied by lung damage by rib fragments;
- open chest injuries (penetrating wounds);
- iatrogenic injuries (as a complication of therapeutic or diagnostic manipulations – lung damage during subclavian catheter placement, intercostal nerve block, pleural puncture);
- artificially induced pneumothorax – an artificial pneumothorax is applied for the treatment of pulmonary tuberculosis, for the purpose of diagnosis — during thoracoscopy.
2. Diseases of the lungs and organs of the thoracic cavity:
- nonspecific character – due to rupture of air cysts in bullous disease (emphysema) of the lungs, breakthrough of the lung abscess into the pleural cavity (pyopneumothorax), spontaneous rupture of the esophagus;
- of a specific nature – pneumothorax due to the rupture of caverns, the breakthrough of caseous foci in tuberculosis.
Symptoms of pneumothorax
The severity of the symptoms of pneumothorax depends on the cause of the disease and the degree of compression of the lung.
A patient with an open pneumothorax assumes a forced position, lying on the injured side and tightly clamping the wound. Air is sucked into the wound with noise, foamy blood with an admixture of air is released from the wound, the chest excursion is asymmetric (the affected side lags behind when breathing).
The development of spontaneous pneumothorax is usually acute: after an attack of coughing, physical effort, or for no apparent reason. At the typical onset of pneumothorax, a piercing stabbing pain appears on the side of the affected lung, radiating into the arm, neck, and sternum. The pain increases with coughing, breathing, the slightest movement. Often, pain causes the patient to have a panic fear of death. Pain syndrome in this disease is accompanied by shortness of breath, the severity of which depends on the volume of lung decline (from rapid breathing to severe respiratory failure). There is pallor or cyanosis of the face, sometimes a dry cough.
After a few hours, the intensity of pain and shortness of breath weaken: the pain bothers at the moment of deep inspiration, shortness of breath manifests itself with physical effort. It is possible to develop subcutaneous or mediastinal emphysema – the release of air into the subcutaneous tissue of the face, neck, chest or mediastinum, accompanied by swelling and a characteristic crunch during palpation. Auscultation on the side of the pneumothorax, breathing is weakened or not listened to.
In about a quarter of cases, spontaneous form has an atypical onset and develops gradually. Pain and shortness of breath are insignificant, as the patient adapts to new breathing conditions, they become almost invisible. The atypical form of the flow is characteristic of a limited pneumothorax, with a small amount of air in the pleural cavity.
Clearly clinical signs are determined when the lung subsides by more than 30-40%. 4-6 hours after the development of spontaneous pneumothorax, an inflammatory reaction from the pleura joins. After a few days, the pleural leaves thicken due to fibrin overlays and edema, which subsequently leads to the formation of pleural accretions that make it difficult to straighten the lung tissue.
Complicated course of pneumothorax occurs in 50% of patients. The most common complications of pneumothorax are:
- exudative pleurisy
- hemopneumothorax (when blood enters the pleural cavity)
- pleural empyema (pyopneumothorax)
- rigid lung (not straightening as a result of the formation of mooring – connective tissue strands)
- acute respiratory failure
With spontaneous and especially valvular pneumothorax, subcutaneous and mediastinal emphysema may be observed. Spontaneous form occurs with relapses in almost half of patients.
Already during the examination of the patient, characteristic signs of pneumothorax are revealed:
- the patient assumes a forced sitting or semi-sitting position;
- the skin is covered with cold sweat, shortness of breath, cyanosis;
- expansion of intercostal spaces and chest, restriction of chest excursion on the affected side;
- decrease in blood pressure, tachycardia, displacement of the boundaries of the heart in a healthy direction.
Specific laboratory changes in pneumothorax are not determined. The final confirmation of the diagnosis occurs after an X-ray examination. When lung x-ray on the side of the pneumothorax, an area of enlightenment is determined, devoid of a pulmonary pattern on the periphery and separated by a clear border from the collapsed lung; the displacement of the mediastinal organs to the healthy side, and the dome of the diaphragm downwards. With the behavior of a diagnostic pleural puncture, air is obtained, the pressure in the pleural cavity fluctuates within zero.
Treatment of pneumothorax
Pneumothorax is an urgent condition requiring immediate medical attention. Anyone should be ready to provide emergency assistance to a patient with pneumothorax: calm down, provide sufficient oxygen access, call a doctor immediately.
With an open pneumothorax, first aid consists in applying an occlusive dressing that hermetically closes the defect in the chest wall. An air-tight bandage can be made of cellophane or polyethylene, as well as a thick cotton-gauze layer. In the presence of a valvular pneumothorax, an urgent pleural puncture is necessary in order to remove free gas, straighten the lung and eliminate the displacement of the mediastinal organs.
Patients are hospitalized in a surgical hospital (if possible in specialized pulmonology departments). Medical care for pneumothorax consists of puncture of the pleural cavity, evacuation of air and restoration of negative pressure in the pleural cavity.
With a closed pneumothorax, air aspiration is carried out through a puncture system (a long needle with an attached tube) in a small operating room with asepsis. Pleural puncture in pneumothorax is performed on the side of the lesion in the second intercostal space along the midclavicular line, along the upper edge of the underlying rib. With a total pneumothorax, in order to avoid rapid expansion of the lung and the shock reaction of the patient, as well as with defects in the lung tissue, drainage is installed into the pleural cavity, followed by passive aspiration of air by Bulau, or active aspiration by means of an electric vacuum apparatus.
Treatment of an open pneumothorax begins with its transfer to a closed one by suturing the defect and stopping the flow of air into the pleural cavity. In the future, the same measures are carried out as with a closed pneumothorax. Valvular pneumothorax in order to lower intrapleural pressure is first turned into an open one by puncture with a thick needle, then its surgical treatment is carried out.
An important component of the treatment is adequate anesthesia both during the decline of the lung and during its expansion. For this purpose, cervical vagosympathetic blockades are used. In order to prevent relapses of pneumothorax, pleurodesis is performed with talc, silver nitrate, glucose solution or other sclerosing drugs, artificially causing an adhesive process in the pleural cavity. With recurrent spontaneous pneumothorax caused by bullous emphysema, surgical treatment (removal of air cysts) is indicated.
Prognosis and prevention
With uncomplicated forms of spontaneous form, the outcome is favorable, however, frequent relapses of the disease are possible in the presence of lung pathology.
There are no specific methods for the prevention of pneumothorax. It is recommended to carry out timely medical and diagnostic measures for lung diseases. Patients who have undergone pneumothorax are recommended to avoid physical exertion, to be examined for HCL and tuberculosis. Prevention of recurrent pneumothorax consists in surgical removal of the source of the disease.