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.

The causes and pathogenesis of spontaneous pneumothorax

Pneumothorax, which occurs as a result of the destruction of lung tissue during a severe pathological process (abscess, gangrene of the lung, breakthrough of the tuberculous cavern, etc.) is considered symptomatic (secondary). Spontaneous pneumothorax, which develops without a clinically pronounced previous disease, including those considered to be practically healthy, is called idiopathic. To the development of idiopathic pneumothorax leads mostly limited bullous emphysema, the etiology of which is unknown. Sometimes bullous emphysema develops with congenital insufficiency of alpha2-antitrypsin, which leads to enzymatic destruction of the lung tissue by proteolytic enzymes predominantly on the streets of a young age. In some cases, idiopathic spontaneous pneumothorax is associated with a congenital constitutional weakness of the pleura, which is easily broken by a strong cough, laughter, deep breathing, intense physical effort.

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

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

The appearance of air in the pleural cavity significantly increases the intrapleural pressure (normally the pressure in the pleural cavity is below the atmospheric pressure due to the elastic traction of the lungs), which results in the compression and collapse of the lung tissue, the mediastinal displacement in the opposite direction, the descent of the diaphragm dome, compression and kink of large blood vessels in the mediastinum. All these factors lead to impaired breathing, blood circulation.

Classification of spontaneous pneumothorax (NV Putov, 1984)

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

The total is called pneumothorax in the absence of pleural joints (regardless of the degree of collapse of the lung), partial (partial) - with obliteration of part of the pleural cavity.

There are open, closed and valve (strained) pneumothorax.

With open pneumothorax there is a pleural cavity with a bronchus lumen and, consequently, with atmospheric air. On inspiration, air enters the pleural cavity, and exhales out of it through a defect in the visceral pleura.

In the future, the defect in the visceral pleura is closed by fibrin and closed pneumothorax is formed, while the communication between the pleural cavity and the atmospheric air stops.

It is possible to form a strained pneumothorax (with positive pressure in the pleural cavity). This type of pneumothorax arises when the valve mechanism operates in the area of bronchopleural communication (fistula), which allows air to enter the pleural cavity, but does not allow it to leave it. As a result, the pressure in the pleural cavity progressively increases and exceeds the atmospheric pressure. This leads to complete collapse of the lung and a significant displacement of the mediastinum in the opposite direction.

After 4-6 hours of pneumothorax development, inflammatory reaction of the pleura occurs, after 2-5 days of the pleura thickens due to edema and a layer of fallen fibrin, subsequently pleural adhesions form, which can complicate the spreading of the lung.

Symptoms of spontaneous pneumothorax

Spontaneous pneumothorax develops more often in young men of high growth at the age of 20-40 years.

In 80% of cases, the disease begins acutely. In typical cases, sudden acute stitching pain appears in the corresponding half of the chest with irradiation in the neck, arm, sometimes in the epigastric region. Quite often the pain is accompanied by a feeling of fear of death. Pain can occur after intense physical exertion, when coughing, often the pain appears in a dream. Often the cause contributing to the appearance of pain remains unknown.

The second characteristic sign of the disease is a sudden shortness of breath. The degree of dyspnoea is different, breathing in patients with rapid, superficial, but extremely pronounced respiratory failure usually does not happen or it is very rare. Some patients develop a dry cough.

After a few hours (sometimes minutes), pain and dyspnea decrease; pain can be disturbed only with a deep breath, shortness of breath - with physical exertion.

In 20% of patients, spontaneous pneumothorax can begin atypically, gradually, hardly noticeable for the patient. In this case the pain and dyspnea are not very pronounced, they may appear indeterminate and quickly disappear as the patient adapts to the changed conditions of breathing. Yet atypical flow is more often observed when small amounts of air enter the pleural cavity.

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

• forced position of the patient (sedentary, half-sitting), the patient is covered with cold sweat;
• cyanosis, dyspnea, chest and intercostal spaces widening, and also restriction of respiratory movements of the chest on the side of the lesion;
• Tympanitis with percussion of the lungs on the corresponding side;
• weakening or absence of vocal jitter and vesicular breathing on the affected side;
• displacement of the region of the cardiac shock and the boundaries of cardiac dullness in a healthy way, tachycardia, lowering of blood pressure.

It should be pointed out that the physical symptoms of pneumothorax with a small accumulation of air in the pleural cavity may not be detected. All physical signs of pneumothorax are clearly defined only when there is a decrease in the lung by 40% or more.

Instrumental research

Radiography of the lungs reveals the characteristic changes on the side of the lesion:

• the area of enlightenment, devoid of pulmonary pattern, located along the periphery of the pulmonary field and separated from the collapsed lung by a clear boundary. With a small pneumothorax, these changes on the chest X-ray may not be noticeable. In this case, it is necessary to make an x-ray while exhaling;
• displacement of the mediastinum towards the healthy lung;
• displacement of the dome of the diaphragm downwards.

Smaller in volume pneumothorax is better detected in lateroposition - on the side of pneumothorax there is a deepening of the rib-diaphragmatic sinus, a thickening of the contours of the lateral surface of the diaphragm.

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

With pleural puncture, a free gas is found, intrapleural pressure fluctuates around zero.

Laboratory data

There are no significant changes.

The course of spontaneous pneumothorax

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

Spontaneous pneumothorax examination program

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

[1], [2], [3], [4]