Pneumothorax refers to a disruption of the integrity and confinement of the pleural cavity in which gas enters and accumulates in the pleural cavity. in 1724, Boerhaave described a massive accumulation of gas in the pleural cavity with pulmonary atrophy in a report on spontaneous esophageal rupture, thus reporting for the first time this type of pneumothorax occurring without chest trauma. in 1826, Laennee described the clinical features of pneumothorax. In 1932, Kjaergaard first emphasized the existence of a non-tuberculous etiology in the majority of pneumothorax patients. Depending on the etiology of pneumothorax formation, there are spontaneous and traumatic pneumothoraxes. Spontaneous pneumothorax refers to the accumulation of gas in the pleural cavity due to the rupture of the parenchyma or dirty pleura without exogenous or intervening factors.
Symptoms and signs
1.Difficulty in breathing
All patients have dyspnea during pneumothorax attack, and its severity is related to the process of attack, the degree of lung compression and the original lung function status. In young patients with normal respiratory function, there can be no obvious dyspnea, even if the lung is compressed >80%, they can only feel chest tightness slightly when moving, while in elderly patients with chronic obstructive pulmonary emphysema, there is obvious dyspnea when the lung is lightly compressed. In acute onset pneumothorax, the symptoms may be more obvious, while in chronic onset pneumothorax, the healthy side of the lung can compensate for the expansion and the clinical symptoms may be milder.
2.Chest pain
Sudden sharp stabbing and knife-cutting pain often occurs at the time of pneumothorax, which is not related to the sudden rupture of the pulmonary blister and the degree of lung compression, but may be related to the increased pressure in the pleural cavity and the distension of the wall pleura. The site of pain is uncertain and may be confined to the chest, but may also radiate to the shoulders, back, and upper abdomen. Persistent retrosternal pain may be present in the presence of obvious mediastinal emphysema. Pain is the most common complaint of pneumothorax patients and may be the only symptom in mild pneumothorax.
3.Irritating cough: Occasional irritating cough in spontaneous pneumothorax.
4.Other symptoms: When pneumothorax is combined with hemopneumothorax, the patient will have palpitations, low blood pressure, and chills in the extremities if there is a lot of bleeding.
Pathological etiology
The etiological composition of spontaneous pneumothorax has changed with the development of society and medicine. 1932 Kjaergarrd reported that the etiology of spontaneous pneumothorax was mostly subpleural pulmonary blisters. 1950s, tuberculosis became a common cause of spontaneous pneumothorax. After the 1980s, with the aging of the population, the rate of spontaneous pneumothorax caused by chronic obstructive pulmonary disease (COPD) in the elderly tended to increase. The incidence of spontaneous pneumothorax caused by Pneumocystis carinii infection in patients with acquired immunodeficiency syndrome (AIDS) has also increased with the emergence of some specific social phenomena.
Spontaneous pneumothorax is classified according to the cause of gas spillage into the pleural cavity: idiopathic pneumothorax and secondary pneumothorax. Idiopathic pneumothorax is most often seen in adolescents with a thin and tall body shape, and no clear lesion is often seen on the surface of the dirty pleura on X-ray chest films or even under direct view of open-heart surgery. Secondary pneumothorax is more common in middle-aged and elderly people, often due to the rupture of pre-existing lesions in the lung, such as pulmonary herpes, tuberculosis, lung abscess, lung cancer, etc. The clinical signs and symptoms of patients with pneumothorax depend on the underlying etiology, the degree of pulmonary atrophy, and the presence or absence of underlying lung disease.
The common etiologies of spontaneous pneumothorax are as follows.
1. Rupture of subpleural pneumomediastinum
Spontaneous pneumothorax in adolescents is mostly caused by rupture of subpleural pulmonary blisters in the apical part of the lung. Most subpleural pulmonary blisters are divided into two categories, subpleural microscopic pulmonary blisters (bleb), <1 cm in diameter, often multiple, which can occur in the apical part of the lung, the edge of the interlobular fissure and the edge of the lower lobe of the lung. These tiny pulmonary blisters are often the result of straining and poor ventilation during the healing of bronchial and pulmonary inflammation and fibrous tissue scar formation. The spontaneous pneumothorax caused by subpleural pneumomediastinum is not easily detected on X-ray chest film or during surgery, so it is also called "idiopathic pneumothorax". Subpleural pulmonary blisters are often solitary and occur mostly in the apical part of the lung, due to congenital hypoplasia of the dirty pleura and the gradual appearance of pulmonary blisters, which are commonly found in thin and tall adolescents. These two types of spontaneous pneumothorax caused by ruptured pulmonary blisters can be induced after vigorous activity, coughing and sneezing, or can occur in a quiet state.
2.Rupture of large alveolar emphysema
Due to chronic obstructive pulmonary disorders, the alveolar units are over-inflated and the alveolar wall is destroyed after a long time, i.e. lobar-centered emphysema and full lobar emphysema, and the alveoli are further fused to compress the alveolar septum and interstitial lung to form alveolar emphysema, which is characterized by the extremely thin blood vessels and alveolar septum that are compressed in the alveoli on X-ray chest film and chest CT film, so as to distinguish it from giant pulmonary blister. Pneumothorax occurs when the residual air volume in the lung parenchyma increases further and the pressure is too high causing the rupture of the dirty pleura. it is common in men over 40 years old, often accompanied by chronic cough, long-term smoking history, bronchial asthma history, etc.
3.Tuberculosis
In the 1950s, pulmonary tuberculosis was one of the very important factors causing spontaneous pneumothorax, and its pathogenesis is mainly due to.
① contraction of old tuberculous scar, resulting in distortion and obstruction of small bronchi and formation of confined pulmonary macula rupture.
(ii) direct rupture of active tuberculous cavities in the lung.
③ Indirectly caused by tuberculosis-damaged lung causes compensatory emphysema in the contralateral lung tissue, which causes rupture of its distal alveoli by over-expansion when infection and bronchial obstruction occur. in the 1980s, with the application of effective anti-tuberculosis drugs, the incidence of pulmonary tuberculosis decreased significantly.