Spontaneous pneumothorax: causes, symptoms, diagnosis, treatment

Spontaneous pneumothorax is a pathological condition characterized by the accumulation of air between the visceral and parietal pleura, not associated with mechanical damage to the lung or chest as a result of trauma or medical manipulation.

Causes and pathogenesis of spontaneous pneumothorax

Pneumothorax, which occurs due to the destruction of lung tissue in a severe pathological process (abscess, pulmonary gangrene, rupture of a tuberculous cavity, etc.), is considered symptomatic (secondary). Spontaneous pneumothorax, developing without a clinically expressed previous disease, including in individuals considered practically healthy, is called idiopathic. The development of idiopathic pneumothorax most often leads to limited bullous emphysema, the etiology of which is unknown. Sometimes bullous emphysema develops with congenital deficiency of alpha2-antitrypsin, which leads to enzymatic destruction of lung tissue by proteolytic enzymes, mainly in young people. In some cases, idiopathic spontaneous pneumothorax is associated with congenital constitutional weakness of the pleura, which is easily ruptured by strong coughing, laughter, deep breathing, intense physical effort.

Sometimes spontaneous pneumothorax occurs during deep immersion in water, diving, or during a flight in an airplane at high altitude, probably due to pressure changes that are unevenly transmitted to different parts of the lungs.

The main causes of symptomatic pneumothorax are: pulmonary tuberculosis (breakthrough of caseous foci or cavities located near the pleura into the pleural cavity); complications of pneumonia - pleural empyema, abscess and gangrene of the lungs; bronchiectasis; congenital pulmonary cysts; echinococcal cysts and pulmonary syphilis; malignant tumors of the lungs and pleura; breakthrough of carcinoma or diverticulum of the esophagus, subphrenic abscess into the pleura.

The appearance of air in the pleural cavity significantly increases the intrapleural pressure (normally the pressure in the pleural cavity is lower than atmospheric pressure due to the elastic traction of the lungs), resulting in compression and collapse of the lung tissue, displacement of the mediastinum to the opposite side, lowering of the dome of the diaphragm, compression and bending of large blood vessels in the mediastinum. All these factors lead to impaired breathing and blood circulation.

Classification of spontaneous pneumothorax (N.V. Putov, 1984)

1. By origin:
   1. Primary (idiopathic).
   2. Symptomatic.
2. By prevalence:
   1. Total.
   2. Partial.
3. Depending on the presence of complications:
   1. Uncomplicated.
   2. Complicated (bleeding, pleurisy, mediastinal emphysema).

Pneumothorax is called total in the absence of pleural adhesions (regardless of the degree of lung collapse), partial - when part of the pleural cavity is obliterated.

A distinction is made between open, closed and valvular (tension) pneumothorax.

In open pneumothorax, there is a communication between the pleural cavity and the lumen of the bronchus and, consequently, with atmospheric air. During inhalation, air enters the pleural cavity, and during exhalation, it leaves it through a defect in the visceral pleura.

Subsequently, the defect in the visceral pleura is closed by fibrin and a closed pneumothorax is formed, while communication between the pleural cavity and the atmospheric air ceases.

Tension pneumothorax (with positive pressure in the pleural cavity) may develop. This type of pneumothorax occurs when the valve mechanism in the area of the bronchopleural communication (fistula) operates, allowing air to enter the pleural cavity but preventing it from exiting. As a result, the pressure in the pleural cavity progressively increases and exceeds atmospheric pressure. This leads to complete collapse of the lung and significant displacement of the mediastinum to the opposite side.

After 4-6 hours of pneumothorax development, an inflammatory reaction of the pleura occurs; after 2-5 days, the pleura thickens due to edema and a layer of fallen fibrin; subsequently, pleural adhesions form, which can make it difficult for the lung to straighten.

Symptoms of spontaneous pneumothorax

Spontaneous pneumothorax most often develops in young, tall men aged 20-40 years.

In 80% of cases, the disease begins acutely. In typical cases, a sharp, stabbing, piercing pain suddenly appears in the corresponding half of the chest, radiating to the neck, arm, and sometimes to the epigastric region. Quite often, the pain is accompanied by a feeling of fear of death. Pain may occur after intense physical exertion, when coughing, and pain often appears in sleep. Often, the cause of the pain remains unknown.

The second characteristic sign of the disease is sudden shortness of breath. The degree of shortness of breath varies, patients breathe quickly and shallowly, but extremely severe respiratory failure usually does not occur or occurs very rarely. Some patients develop a dry cough.

After a few hours (sometimes minutes) the pain and shortness of breath decrease; the pain may only bother you with a deep breath, and shortness of breath - with physical exertion.

In 20% of patients, spontaneous pneumothorax may begin atypically, gradually, and unnoticeably for the patient. In this case, pain and dyspnea are expressed slightly, may seem vague and quickly disappear as the patient adapts to the changed breathing conditions. However, an atypical course is more often observed when small amounts of air enter the pleural cavity.

Examination and physical examination of the lungs reveal the classic clinical symptoms of pneumothorax:

• forced position of the patient (sitting, semi-sitting), the patient is covered in cold sweat;
• cyanosis, shortness of breath, expansion of the chest and intercostal spaces, as well as limitation of respiratory movements of the chest on the affected side;
• tympanitis on percussion of the lungs on the corresponding side;
• weakening or absence of vocal fremitus and vesicular breathing on the affected side;
• displacement of the area of the cardiac impulse and the boundaries of cardiac dullness towards the healthy side, tachycardia, decreased blood pressure.

It should be noted that physical symptoms of pneumothorax may not be detected with a small accumulation of air in the pleural cavity. All physical signs of pneumothorax are clearly determined only when the lung collapses by 40% or more.

Instrumental research

X-ray of the lungs reveals characteristic changes on the affected side:

• an area of enlightenment, devoid of pulmonary pattern, located on the periphery of the pulmonary field and separated from the collapsed lung by a clear border. In the case of a small pneumothorax, these changes may not be noticeable on an inhalation radiograph. In this case, an exhalation radiograph must be taken;
• displacement of the mediastinum towards the healthy lung;
• downward displacement of the diaphragm dome.

A small pneumothorax is better detected in the lateral position - on the side of the pneumothorax, a deepening of the costophrenic sinus and thickening of the contours of the lateral surface of the diaphragm are noted.

The ECG reveals a deviation of the electrical axis of the heart to the right, an increase in the amplitude of the P wave in leads II and III, and a decrease in the amplitude of the T wave in the same leads.

Pleural puncture reveals free gas, and intrapleural pressure fluctuates around zero.

Laboratory data

There are no characteristic changes.

Course of spontaneous pneumothorax

The course of uncomplicated spontaneous pneumothorax is usually favorable - air stops flowing into the pleural cavity from the collapsed lung, the defect in the visceral pleura is closed with fibrin, and the air is gradually absorbed, which takes about 1-3 months.

Examination program for spontaneous pneumothorax

1. General blood and urine analysis.
2. Fluoroscopy, radiography of the heart and lungs.
3. ECG.

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