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What is pneumothorax?
A pneumothorax is a collapsed lung, a condition that occurs when air leaks into the cavity between the lungs and chest wall. This cavity is known as the pleural space.
A pneumothorax can range in its severity. Small pneumothoraces that are not associated with any complications can heal on their own, whereas more serious cases that involve large volumes of trapped air may become fatal if medical care is not sought.
Air can enter the pleural space if there is a hole in the lung or the chest wall. The air accumulates inside the pleural space, pushes on the outside of the lung and causes it to collapse. A collapsed lung cannot expand as normal, and therefore breathing is restricted and the body cannot receive as much oxygen as it normally does.
Some factors that can increase the risk of developing a pneumothorax include:
There are different types of pneumothoraces, and each is classified according to its specific cause.
Primary spontaneous pneumothorax
This occurs when there is no known underlying lung condition, and without any inciting event. It:
- Is most common in thin and tall adult men aged between 18-40 years;
- Rarely occurs over the age of 40;
- Typically occurs during rest, but may also occur during diving or high-altitude flying due to pressure changes in the lungs;
- Is more common in smokers;
- Is often caused by the rupture of an air-filled sac within the lung, called a bleb, and;
- Has a recurrence rate of around 20%.
Secondary spontaneous pneumothorax
This occurs as a complication of an underlying lung condition, typically in people over 60 years of age. Secondary spontaneous pneumothorax:
- Is most often caused by the rupture of a bleb or bulla, and;
- Tends to be more serious than primary spontaneous pneumothorax, due to the more compromised health of the people in this group.
A traumatic pneumothorax is caused by a blunt or penetrating chest injury, such as from:
- A stab wound;
- A fractured rib, or;
- An airbag impact in a motor vehicle accident.
A catamenial pneumothorax occurs in women only, within 72 hours from the onset of menstruation. It is caused by thoracic endometriosis. This generally occurs in women between 30-40 years of age, and more commonly occurs in the right lung.
Signs and symptoms
The symptoms of pneumothorax may vary depending on the size and type of pneumothorax, and whether there is an underlying medical condition.
Some people may not experience any symptoms. If symptoms do occur, they may include:
Methods for diagnosis
Diagnosis of a pneumothorax is typically based on a physical examination to assess lung function, and to see if there is any compression on one side of the chest.
A pneumothorax is usually diagnosed with a chest X-ray. Other tests that may be carried out to confirm a pneumothorax include:
Types of treatment
Treatment of a pneumothorax is aimed at removing air from the pleural space and preventing its recurrence. Treatment will vary depending on the symptoms, the size of the pneumothorax and its cause.
There are both surgical and non-surgical treatment options:
Non-surgical treatment can be used for most cases of uncomplicated primary spontaneous pneumothorax.
'Watchful waiting' may be sufficient for small and symptomatic primary spontaneous pneumothoraces.
Needle aspiration and chest tube insertion
Needle aspiration may be used to remove excess air from the pleural space. Needle aspiration involves inserting a tube between the ribs and using a syringe or suction device to extract the air. Larger pneumothoraces may require a chest tube that will stay in place for a few days.
Surgical treatment may be used for repeated episodes, or when the lung has not expanded after five days with a chest tube in place.
Video-assisted thoracoscopic surgery (VATS)
Video-assisted thoracoscopic surgery is effective both in treating a spontaneous pneumothorax and preventing it from recurring. Surgery may involve the removal of the bleb or bullae, and manipulation of the lung to make it stick to the chest wall. The rate of recurrence is reduced to less than 5% with VATS.  Alternatively, chemical pleurodesis can be used to prevent further pneumothorax.
Chemical pleurodesis involves the insertion of a chemical irritant into the pleura through a chest tube to cause the pleura to stick together. It decreases the recurrence rate to around 20-25%.
Thoracotomy - making an open incision in the chest - has mostly been replaced by VATS (see above) in treating pneumothorax, as VATS involves a shorter hospitalisation and less pain. Thoracotomy is recommended in certain cases where VATS is not available, or if it has failed.
This serious complication can occur in any person with a pneumothorax, but is more common in people who are receiving positive-pressure ventilation, such as mechanical ventilation or during resuscitation. It occurs when air becomes trapped in the pleural space and creates enough pressure to put pressure on nearby organs and blood vessels. The pressure can limit the flow of blood back to the heart, which can quickly lead to loss of heart function and loss of breathing.
A tension pneumothorax is a life-threatening emergency, and is treated by performing an emergency needle decompression, which involves inserting a needle into the pleural space to relieve any pressure.
Air leaks are usually caused by the original problem that led to the development of the pneumothorax. They are more common in secondary spontaneous pneumothoraces and most cases will resolve on their own within a week.
Failure of lung expansion
The lung can fail to expand when there is a persistent air leak, the lung is trapped, or a chest tube has been poorly positioned. If the lung remains collapsed for more than a week, treatment may involve VATs.
Re-expansion pulmonary oedema
This rare complication can occur in certain situations when air is emptied quickly from the pleural space. The lung may fill up with fluid, causing difficulty breathing. Treatment of re-expansion pulmonary oedema involves supportive care with oxygen, diuretics and cardiopulmonary support as required.
The outcome for pneumothorax depends on its size and type. Smaller pneumothoraces can heal on their own, whereas pneumothoraces associated with underlying conditions require treatment. While death from pneumothorax is rare, there is a high rate of recurrence.
Quitting smoking can decrease the chance of pneumothorax.