Definition

Pneumothorax is the accumulation of air outside the lungs, within the pleural cavity (the space between the lungs and the chest wall). This occurs when air leaks into the pleural space, exerting pressure on the lungs from the outside, leading to lung collapse. Air can enter the pleural cavity through two mechanisms: external injuries causing a connection outside the body to the chest wall or from within the lungs, such as due to the rupture of the pleura (the outer layer of the lung). Pneumothorax can result in either total lung collapse or collapse of only part of the lung.

Causes

There are two types of pneumothorax: traumatic and non-traumatic. The non-traumatic type is further divided into two subtypes: primary and secondary. Primary spontaneous pneumothorax occurs spontaneously without an obvious cause, while secondary spontaneous pneumothorax is caused by underlying lung diseases.

In general, pneumothorax can be caused by:

• Chest injuries: Any chest injury, whether sharp or blunt, can lead to lung collapse. Injuries may result from physical violence, traffic accidents, or medical procedures involving needle insertion into the chest.
• Lung diseases: Damage to lung tissue can trigger lung collapse. This damage can stem from various underlying conditions, such as chronic obstructive pulmonary disease (COPD), cystic fibrosis, lung cancer, or pneumonia. Cystic lung diseases like lymphangioleiomyomatosis and Birt-Hogg-Dube syndrome can create thin-walled air sacs in lung tissue that are prone to rupture, causing pneumothorax.
• Rupture of air-filled blisters: Small blisters (blebs) may form on the upper part of the lungs. These blebs can rupture, releasing air into the surrounding space.
• Mechanical ventilation: Severe pneumothorax can occur in individuals using respiratory support devices. Ventilators may disrupt air pressure balance within the chest, potentially leading to complete lung collapse.

Risk factor

Generally, men are more susceptible to pneumothorax than women. Pneumothorax resulting from the rupture of air-filled blisters (blebs) is most common among individuals aged 20-40 years, particularly in tall, slender individuals with a body mass index below 18 kg/m2.

Underlying lung disease or mechanical ventilation isn't always the direct cause of pneumothorax but can serve as a risk factor.

Other risk factors include:

• Smoking: The longer and more cigarettes a person smokes, the higher their risk of pneumothorax, even in the absence of emphysema or COPD.
• Genetics: Certain types of pneumothorax are believed to have a hereditary component.
• History of previous pneumothorax: Individuals who have had pneumothorax before are at increased risk of experiencing it again.

Symptoms

The primary symptoms of pneumothorax typically include sudden chest pain and shortness of breath. The chest pain is sharp, and severe, and often radiates to the same-side shoulder. The severity of symptoms correlates with the degree of collapsed lung volume. In primary spontaneous pneumothorax, symptoms may be minimal.

Other symptoms may include:

• Rapid breathing
• Asymmetric chest expansion during breathing
• Elevated pulse rate
• Bluish discoloration of the lips or fingers
• Reduced consciousness in severe and life-threatening cases
• Diagnosis
• Pneumothorax is generally diagnosed through chest X-rays. In some cases, a CT scan may be necessary to provide more detailed images of the lungs. Ultrasound examination (USG) can also help detect pneumothorax.

Diagnosis

In general, pneumothorax is diagnosed using chest X-rays. In some cases, a CT scan may be necessary to provide more detailed lung images. Ultrasound examination (USG) can also be useful for identifying pneumothorax.

Management

The main goal of pneumothorax therapy is to reduce or eliminate pressure on the lungs so that they can expand during breathing. The second goal is to prevent recurrence, although this depends on the underlying cause.

Treatment options are tailored to the severity of lung collapse and the patient's overall health condition. Therapies may include:

• Observation: If only a small portion of the lung is affected, monitoring through serial X-ray examinations may suffice until the trapped air is completely reabsorbed, and the lung re-expands to its normal state. This natural healing process may take several weeks.
• Needle aspiration or chest tube insertion: In cases of larger lung collapses, needle aspiration or chest tube insertion may be necessary to remove trapped air. Needle aspiration involves inserting a hollow needle connected to a small tube (catheter) into the air-containing space through the rib space. The tube is connected to a syringe to draw out air, facilitating lung expansion. Chest tube insertion involves placing a flexible tube into the air-containing space, connected to a device with a one-way valve that continuously removes air until lung expansion occurs.
• Non-surgical repair: If chest tube insertion fails to promote lung expansion, non-surgical methods to close the leak may be attempted. This can involve instilling a solution to irritate lung tissue, using blood to form a clot on the lung, or inserting a bronchoscope to install a one-way valve.
• Surgery: Surgery may be required in cases where the leak cannot be closed by other means, especially with a large or persistent air leak. Minimally invasive procedures using fibre-optic cameras and small instruments can be employed to visualize and repair the leaking area or ruptured air blister.
• Oxygen therapy: Oxygen therapy can aid in the reabsorption of air and promote lung expansion.

During the recovery period, certain activities should be avoided as they can exert additional pressure on the lungs. Patients should consult with their healthcare provider regarding restrictions on activities such as flying, diving, and playing wind instruments.

Complications

Possible complications that can occur due to pneumothorax vary depending on the size and severity of the pneumothorax, as well as the cause and therapy given. In some cases, the opening where the air leak occurs cannot close, causing air to continue leaking. Some people also experience recurrence. Meanwhile, in severe cases and without prompt therapy, pneumothorax can be life-threatening.

Prevention

If you have certain medical conditions or a family history of pneumothorax, there may be no specific way to prevent pneumothorax. However, there are ways to reduce the risk of pneumothorax, such as:

• Quitting smoking
• Avoiding or limiting activities that cause drastic changes in air pressure, such as flying and diving
• Regular health check-ups to monitor lung conditions

When to see a doctor? 

Symptoms of pneumothorax can be caused by many underlying diseases, and some can be life-threatening. If you experience severe chest pain or increased shortness of breath, immediately go to the nearest emergency department.