Pleural cavity: connecting element between the lung and the chest wall.
Spontaneous pneumothorax is divided into several subcategories:
- NEOATAL SPONTANEOUS PNEUMOTHORAX: newborns suffering from serious lung diseases such as SAM ( meconium aspiration syndrome ) and RDS (respiratory distress syndrome) can develop complications such as spontaneous pneumothorax. The majority of newborns affected by spontaneous pneumothorax do not complain of symptoms : this constitutes a serious limitation for an early diagnosis. In other newborns, however, the pathology begins with evident prodromes, such as cyanosis , hypoxia , hypercapnia and bradycardia .
- PRIMARY OR PRIMITIVE SPONTANEOUS PNEUMOTHORAX: occurs in the absence of an apparent cause or lung disease. Most affected patients recover spontaneously within 7-10 days of onset, without reporting long-term damage. The pathogenesis is generally linked to the rupture of the so-called blebs , accumulations of air lodged between the lung and visceral pleura . It is estimated that the primitive spontaneous variant constitutes 50-80% of spontaneous forms.
- SECONDARY SPONTANEOUS PNEUMOTHORAX: lung collapse is always a consequence of an underlying lung disease. The symptoms are generally more pronounced than in the primary form and the severity of the clinical condition can put the patient’s life at risk (particularly if secondary spontaneous pneumothorax is not adequately treated). In most cases, secondary spontaneous pneumothorax affects people over the age of 40.
From a pathophysiological point of view, a further classification of spontaneous pneumothorax can be made:
- Spontaneous open pneumothorax: air continuously enters and exits the pleural cavity, so the lung collapses completely, as it is subjected to the action of atmospheric pressure .
- Spontaneous closed pneumothorax: the lung is not completely collapsed, since the communication with the pleural cavity is closed, therefore there is no air leak.
- Spontaneous valve pneumothorax (or tension pneumothorax): this is the most dangerous variant of pneumothorax. The air enters the pleural cavity during inhalation, without exiting during exhalation: consequently, the intrapleural pressure increases excessively, to the point of literally crushing the lung. This clinical condition can jeopardize the patient’s survival: tension pneumothorax can progress to the point of inducing restrictive ventilatory deficit and cardiovascular collapse.
Causes And Risk Factors
Spontaneous pneumothorax can result from a rupture of the pulmonary structures and visceral pleura: a similar condition favors the communication of the airways with the thoracic cavity, creating damage.
We have seen that only the secondary variant of spontaneous pneumothorax is related to lung pathologies. Below are the morbid conditions most often observed in affected patients:
- lung abscess
- Cancer: primary lung cancer , carcinoid, mesothelioma , metastatic sarcoma
- Chronic bronchitis associated with pulmonary fibro-emphysema
- thoracic endometriosis
- bullous emphysema (most cases)
- cystic fibrosis
- vascular infarction
- lung infections
- Marfan syndrome (pathology affecting connective tissue )
- ankylosing spondylitis
Although no apparently observable cause is found in patients with primary spontaneous pneumothorax, it is assumed that bubbles ( accumulations of air developed inside the lung) and blebs (accumulations of air lodged between the lung and visceral pleura) can have a major impact on the genesis of the I disturb. It is estimated that in almost all patients with spontaneous pneumothorax, videothoracicoscopy ascertains the presence of these bullous lesions .
The close correlation between the sudden manifestation of the symptoms of spontaneous pneumothorax and the performance of intense sporting activity is notable. In fact, it seems that pulmonary hyperventilation and muscular hyperactivity can be considered possible triggers. In this sense, the sports most at risk are weightlifting and diving. However, it is conceivable that even the appearance or persistence of a particularly irritating cough could cause the pneumothorax to burst.
Despite what has been stated, in the majority of patients spontaneous pneumothorax appears suddenly, even at rest .
During scuba diving, the air breathed through the breathing apparatus must have a pressure equal to the ambient pressure; the same air, however, increases in volume as the environmental pressure decreases, therefore expanding in the ascent section. If the increase in volume is excessive, the rupture of the pulmonary alveoli is conceivable : in similar situations, the passage of air inside the pleural cavity is favored, therefore the collapse of the lung (which results in pneumothorax).
Except for asymptomatic cases, the majority of patients affected by spontaneous pneumothorax complain of a peculiar “pleural” pain, limited to the hemithorax affected by the disease.
The initial clinical symptoms depend on both the patient’s age and the extent of the pneumothorax. In affected children (neonatal spontaneous pneumothorax), for example, a flutter , a vibration at the mediastinal level, is more often observed .
Many hospitalized patients report symptoms reporting expressions such as “violent stabbing chest pain “, often associated with more or less severe breathing difficulties. Dyspnoea _it is clearly due to lung collapse; young people seem to feel this disorder much more lightly than older people .
Furthermore, among the symptoms associated with spontaneous pneumothorax, agitation and the sensation of suffocation cannot be missing, reported by a good part of the patients.
The patient suffering from spontaneous pneumothorax appears in difficulty, often in a clear state of cyanosis. It is sometimes possible to detect tachycardia (>135 bpm), jugular turgidity due to involvement of the vena cava and increase in the size of the hemithorax affected by the pathology.
In patients with severe spontaneous pneumothorax, CT is the diagnostic test par excellence: it is in fact possible to precisely detect the extension of the pneumothorax. This practice also allows us to identify the possible presence of hemothorax (spillage of blood into the pleural cavity) and pulmonary contusions .
The chest x-ray reveals the air accumulated inside the pleural cavity, the lowering of the diaphragm , the subcutaneous emphysema and the collapse of the lung towards the hilum.
The differential diagnosis must be made with:
- pleural effusion → the manifestation of symptoms generally occurs less abruptly than in spontaneous pneumothorax
- chest pain, pleurodynia (severe pain of the pleural nerves and intercostal muscles) and Bornholm disease (infection of the intercostal muscles , with possible involvement of the pleura) → characterized by an unpleasant and constant perception of breathlessness
- pulmonary embolism → among the symptoms we remember hemoptysis and rales in the affected area
In general, we speak of eclectic therapeutic conduct, in the sense that the therapy is heterogeneous and varied, because it is subordinated both to the triggering cause (when identifiable) and to the prediction of spontaneous resorption of the lesion. When the damage is mild and affects a small portion of the lung, spontaneous recovery is expected: in such circumstances, absolute rest is recommended.
Multiple factors intervene in the choice of one therapy rather than another. It is necessary to take into consideration the severity of the symptoms, the age of the patient, the degree of respiratory distress and the underlying pathology (when detectable).
Even in the absence of symptoms (or in case of mild respiratory distress ) the newbornaffected by spontaneous pneumothorax must be carefully monitored. Particular attention must be paid to monitoring heart and respiratory rates, blood pressure and arterial oxygen saturation.
If necessary, oxygen can be administered for a few hours to reduce the pneumothorax and speed up recovery.
For adult men and young people suffering from spontaneous pneumothorax, the treatment of choice is pleural drainage by gravity or aspiration, which is very useful both for removing intrapleural air and for preventing any further accumulation.
Medical statistics show that chest drainage to treat the first episode of spontaneous pneumothorax has a very high success rate, estimated at around 90%. However, in the case of relapses, this value drops to 52% (for the first relapse) and to 15% for the second.
In case of recurrent relapses or failure to respond to pleural drainage, it is conceivable to resort to surgical treatment. Pelurodesis (promotes the adhesion of the lung to the chest wall) or pleurectomy (partial surgical excision of the parietal pleura) are the surgical treatments of choice for the treatment of pneumothorax.
In some particular conditions, surgery is recommended already in the first episode of spontaneous pneumothorax. In similar situations, surgery is the therapy of choice in case of:
- hemopneumothorax (accumulation of air and blood in the pleural cavity)
- bilateral pneumothorax
- past history of contralateral pneumothorax
- tension pneumothorax
In conclusion, it is necessary to request medical assistance even in the event of a suspected onset of lung collapse: in extremely severe cases, in fact, an inadequately treated pneumothorax can degenerate to the point of inducing cardiac arrest, shock, hypoxemia, respiratory failure and death .