Pneumothorax: what causes a lung to collapse?
Written in association with:Our lungs are essential – they provide us with the oxygen we need to live. But what can cause these organs to collapse? Expert cardiothoracic surgeon Ms Emma Beddow is here to explain pneumothorax – a condition that leads to a completely or partially collapsed lung.
What is pneumothorax?
A pneumothorax is a condition in which air or gas is present in the cavity between the lung and the chest wall, causing either partial or complete collapse of the lung.
There are different types of pneumothorax, which can be subdivided into the following:
Traumatic:
These occur following some type of trauma or injury to the chest wall. It can range from minor to significant injury. It pierces the chest wall and can enter the structures within the chest, causing air to leak into the pleural space (the potential space between the lung and the ribcage).
Examples include:
- Broken ribs
- A knife wound or a bullet wound
- Trauma from a road traffic accident
- A medical procedure such as a central venous line insertion
- A significant blow to the chest in contact sports
In addition to these, scuba diving or high-altitude sports can also cause traumatic pneumothorax as the blisters on the surface of the lungs can rupture due to a change in the surrounding pressure.
Non-traumatic:
This does not occur following any injury. It happens spontaneously. There are two major types of spontaneous pneumothorax: primary and secondary.
Primary pneumothorax occurs in the absence of any known lung disease. Most common in young, tall, slim males. In these individuals the surface of the lung has one or more areas of little blisters, which are small, weak, air-filled sacs that can rupture with increased pressure due to, for example, coughing or sneezing.
Secondary pneumothorax occurs in patients with pre-existing lung disorders, usually in older individuals. Conditions such as COPD (chronic obstructive pulmonary disease, for example, emphysema and chronic bronchitis), infections both acute and chronic, lung cancer, cystic fibrosis, and asthma all increase the chance of developing secondary pneumothorax.
Both traumatic and non-traumatic pneumothorax can result in a tension pneumothorax if not adequately treated. This is a medical emergency and can result in cardiac arrest.
What symptoms will I experience if I have a collapsed lung?
A collapsed lung can present with the following symptoms:
- Shortness of breath
- Chest pain which is sharp upon breathing. The pain may extend to the shoulder or round to the back.
- A dry hacking cough, due to irritation of the diaphragm.
- Elevated heart rate
- Breathing faster than usual.
In severe cases, such as tension pneumothorax, the patient’s life may be at risk, with signs of cardiovascular collapse and shock.
A tension pneumothorax is caused when air continues to enter the space between the lung and the ribcage. It is trapped there and, as more air enters, the pressure within the space raises above atmospheric pressure. This causes the lung to be compressed and structures in the midline of the chest to move away from the side of the pneumothorax. The increased pressure puts pressure on the heart and squashes the good lung.
The patient is unable to maintain an adequate oxygen level within their blood, and blood flow back to the heart is decreased due to compression of the veins. Patients have great difficulty breathing and a rapid heart rate, and, if left untreated, this can result in cardiovascular collapse.
How is pneumothorax treated?
Treatment depends on the underlying cause of the pneumothorax.
A small, spontaneous primary pneumothorax may be treated conservatively with observation only. X-rays are taken to ensure the lung hasn’t collapsed further or that the pneumothorax has resolved. If the space is significant, the air may be aspirated with a needle or removed with a chest drain.
Any pneumothorax that persists despite intervention, or if a further episode occurs, then patients are referred for surgical intervention.
Surgery is usually keyhole and involves identifying the area of lung leaking air and removing this area with a stalling device. Sterile talc is insufflated into the chest cavity. This causes inflammation of the lining of the ribcage, which the lung then sticks to, obliterating the potential cavity where air may escape into.
High-risk professionals, such as scuba divers or pilots, may require a bigger operation called a pleurectomy to be able to continue working. Here, the lining on the inside of the ribcage is stripped away and the lung sticks to this raw surface.
Can a collapsed lung recur after treatment?
The outlook following surgical intervention is good. Less than 5% of patients have a recurrence following a talc pleurodesis and less than 1% recur following a pleurectomy.
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