Pneumothorax: Causes, Symptoms, Diagnosis, Types, Mechanism, Risk Factors and Treatment

It is an urgent or emergency situation that must be treated immediately after diagnosis.

Pneumothorax is defined as the presence of air or gas in the pleural cavity (that is, the potential space between the visceral and parietal pleura of the lung), which can affect oxygenation and ventilation.

Clinical results depend on the degree of collapse of the lung on the affected side.

Pneumothorax is divided into primary and secondary.


Collapsed lung can be caused by injury to the lung.

Injuries may include a gunshot or knife wound to the chest, broken ribs, the result of changes in pressure when diving or flying at high altitudes, or certain medical procedures.

Tall, thin people and smokers are at higher risk for collapsed lung.

Lung diseases can also increase the chances of having a collapsed lung.

Some of these diseases are:

  • Asthma
  • Chronic obstructive pulmonary disease.
  • Cystic fibrosis.
  • The tuberculosis.
  • Whooping cough.

In some cases, the lung can spontaneously collapse.

Primary pneumothorax is considered to be one that occurs without an apparent cause and in the absence of significant lung disease.

On the other hand, secondary pneumothorax occurs in the presence of an existing pulmonary pathology.

There is the case where an amount of air in the chest increases markedly and a one-way valve is formed leading to a tension pneumothorax.

Unless reversed by effective treatment, this situation can progress and lead to death.

Pneumothorax can be caused by physical trauma to the chest or as a complication of a medical or surgical intervention (biopsy).

Signs and symptoms of pneumothorax

The signs and symptoms of pneumothorax depend on what the underlying problem is.

Generally speaking, a person can experience any combination of the following symptoms:

  • A sudden type of chest pain, dull, sharp, or stabbing.
  • Chest pain worsens when the person coughs or takes deep breaths.
  • Shortness of breath
  • A quick but shallow breath.
  • Tos.

In the most severe cases of pneumothorax, additional signs and symptoms may appear, including:

  • A blue discoloration of the skin as a result of an inadequate supply of oxygen.
  • Fast heart rate and weak pulse.
  • Anxiety.
  • Enlarged neck veins.
  • Decreased respiration on the side of collapse.
  • Death (potentially) in minutes in the most severe types of pneumothorax, called a tension pneumothorax .

Symptoms generally include chest pain and shortness of breath.

Diagnosing a pneumothorax requires a chest X-ray or CT scan.


The diagnosis will be made with a stethoscope.

If you have a collapsed lung, there is a decrease in breath sounds or no sounds on the side of the affected lung.

The tests that the doctor may require are:

  • An arterial blood gas.
  • Some blood tests.
  • X-rays.
  • A CT scan.
  • An electrocardiogram.

Types of pneumothorax

Spontaneous pneumothorax

Spontaneous pneumothoraces are divided into two types: primary, which occurs in the absence of known lung disease, and secondary, which occurs in someone with underlying lung disease.

Primary spontaneous pneumothorax

Until now, the cause of primary spontaneous pneumothorax has not been identified, however, several risk factors have been identified such as:

  • Smoke.
  • Male.
  • Family history of pneumothorax.

Several underlying mechanisms have been observed.

A primary spontaneous pneumothorax tends to occur in a young adult without underlying lung problems.

Symptoms such as chest pain and sometimes mild dyspnea are often seen .

However, there are several cases in which a primary spontaneous pneumothorax is life threatening to a patient.

Primary spontaneous pneumothorax has been found to rarely cause tension pneumothorax.

Secondary spontaneous pneumothorax

Secondary spontaneous pneumothorax occurs due to underlying chest diseases.

They are more common in patients with chronic obstructive pulmonary disease.

Other known lung diseases that can increase the incidence of pneumothorax are: tuberculosis, necrotizing pneumonia, pneumonocystis carini, lung cancer, lung-related sarcoma, sarcoidosis , endometriosis , cystic fibrosis, severe acute asthma.

Idiopathic pulmonary fibrosis, rheumatoid arthritis, ankylosing spondylitis, polymyositis and dermatomyositis , systemic sclerosis , Marfan syndrome and Ehlers-Danlos syndrome, histiocytosis X, and lymphangioleiomyomatosis.

Secondary spontaneous pneumothoraces, by definition, occur in individuals with significant underlying lung disease.

The following symptoms are generally observed: hypoxemia and hypercapnia in more severe cases.

The sudden onset of dyspnea in patients with known underlying lung diseases, such as; chronic obstructive pulmonary disease, cystic fibrosis or other serious lung diseases should therefore prompt investigations to identify the possibility of a pneumothorax.

Traumatic pneumothorax

Traumatic pneumothorax occurs when the chest wall is perforated, such as when a wound allows air to enter the pleural space.

Traumatic pneumothorax has been found in up to half of all cases of chest trauma, with rib fractures being the most common in this group.

The pneumothorax may be hidden in half of these cases, but it may increase in size, especially if mechanical ventilation is required.

This type of pneumothorax has also been seen in patients already on mechanical ventilation for some other reason.

Mechanism of pneumothorax

The chest cavity contains the lungs, the heart, and many important blood vessels.

On each side of the cavity, a pleural membrane covers the surface of the lung (visceral pleura) and also lines the inside of the chest wall (parietal pleura).

Between the two layers there is a small amount of lubricating serous fluid.

The lungs are fully inflated within the cavity because the pressure within the airways is higher than the pressure within the pleural space.

Pneumothorax can only develop if air is allowed to enter, through damage to the chest wall or damage to the lung itself, or occasionally because microorganisms in the pleural space produce gas.

Risk factor’s

Risk factors are different for a traumatic and spontaneous pneumothorax.

Risk factors for a traumatic pneumothorax include:

  • Play hard contact sports, such as soccer or hockey.
  • Performing stunts that can cause damage to the chest cavity.
  • Have a history of violent fights.
  • Having a recent car accident or falling from a height.
  • Recent medical procedure or assisted respiratory care in progress.

People most at risk for a primary spontaneous pneumothorax include the following:

  • Young boys.
  • Men of slim build.
  • Exposed to changes in atmospheric pressure and severe climatic changes.
  • Smokers


Treatment of pneumothorax depends on several factors and can range from discharge with early follow-up to immediate needle decompression or insertion of a chest tube.

Treatment also depends on the doctor who will handle the patient; pulmonary physicians generally perform a medical (minimally invasive) thoracoscopy, while thoracic surgeons use a suite of surgeries.

In traumatic pneumothorax, the chest tubes are usually inserted and these patients are managed by chest surgeons as other organs of the chest may be affected.

If mechanical ventilation is required, the risk of tension pneumothorax is greatly increased and insertion of a chest tube is mandatory.

Any open chest wound should be covered with an airtight seal, as it carries a high risk of causing tension pneumothorax.

Tension pneumothorax is usually treated with urgent needle decompression.

There are several instances where a “silent lung” is seen and needle decompression may be required prior to transport to the hospital at the scene of the accident, and may be performed by an EMT or other trained professional.

The needle or cannula is left in place until a chest tube can be inserted.

If the tension pneumothorax leads to cardiac arrest, decompression of the needle is done as part of resuscitation as it can restore cardiac output.

Conservative therapy

Small spontaneous pneumothoraces do not always require treatment, as respiratory failure or tension pneumothorax is unlikely, and usually resolve spontaneously.

A case-by-case evaluation and careful follow-up of these patients is needed.

This approach is most appropriate if the estimated size of the pneumothorax is small (defined as less than 50% of the volume of the hemithorax), there is no dyspnea, and there is no underlying lung disease.

A 24-hour observation is optional for these patients or clear instructions are given to return to the hospital if there is a worsening of symptoms.

Outpatient follow-up requires repeat radiographs to confirm improvement.

Secondary pneumothoraces are only treated conservatively if the size is very small (1 cm or less from the air edge) and the symptoms are limited.

Oxygen delivered at a high flow rate can accelerate reabsorption up to four times.


When a secondary spontaneous pneumothorax is large (greater than 50%), or in a secondary spontaneous pneumothorax associated with dyspnea, the guidelines recommend that aspiration size reduction be performed with the insertion of a chest tube.

To perform this procedure, it is necessary to administer local anesthesia and insert a needle connected to a three-way tap.

After follow-up if there has been a significant reduction in the size of the pneumothorax on subsequent X-rays, the rest of the treatment can be conservative.

Compared to tube drainage, first-line aspiration in secondary spontaneous pneumothorax has been shown to significantly reduce the number of people requiring hospitalization, without increasing the risk of complications.

The same technique can also be considered in moderate-size secondary pneumothorax (1–2 cm air margin) without dyspnea, however; Continuous observation in the hospital is required even after a successful procedure.

Chest tube: draining excess air

A chest tube (or intercostal drain) is the most definitive initial treatment for a pneumothorax.

The chest tube is usually inserted into an area under the armpit called the “safe triangle,” where damage to internal organs can be avoided.

Local anesthesia is applied.

Generally, two types of tubes are used.

In spontaneous pneumothorax, small diameter tubes (smaller than 4.7 mm in diameter) can be inserted using the Seldinger technique.

Larger tubes do not have an advantage.

Larger tubes (9.3 mm) have been found to be used for traumatic pneumothorax.

Chest tubes are required in secondary spontaneous pneumothorax that have not responded to needle aspiration.

The method indicates that they are connected to a one-way valve system that allows air to escape, but not re-enter, into the chest.

Several times it includes a water bottle that functions as a water seal or Heimlich valve.

What’s more; they are generally not connected to a negative pressure circuit, as this would lead to rapid expansion of the lung and a risk of pulmonary edema.

The tube is left in place until no air leak is seen for a period of time (no more than 2 days) and the x-rays confirm the re-expansion of the lung.

If after 2 to 4 days there is still evidence of an air leak, there are several options available.

If the air leak persists, surgery may be required.

Chest tubes are also used as first-line treatment when pneumothorax occurs in people with AIDS, usually due to underlying Pneumocystis pneumonia, due to the fact that this condition is associated with prolonged air leakage.

In addition, when bilateral pneumothorax is common in people with a primary spontaneous pneumothorax, surgery is often required.

Pleurodesis and surgery

Pleurodesis is considered the final solution, it is a procedure that permanently closes the pleural space and connects the lung to the chest wall.

Surgical thoracotomy with identification of any source of air leak, followed by pleurectomy of the outer pleural layer and pleural abrasion of the inner layer is considered more effective.

During the healing process, the lung attaches itself to the chest wall, effectively erasing the pleural space.

Recurrence rates are approximately 1%.

Post-thoracotomy pain is generally observed.

A less invasive approach is thoracoscopy, usually in the form of a procedure called video-assisted thoracoscopic surgery.

However, the results of video-assisted thoracoscopic surgery are considered less effective than thoracotomy; smaller scars on the skin.

Chemical pleurodesis involves insufflation of talc.

Talc insufflation induces inflammation of the pleural surfaces.

If a chest tube is already in place, various agents can be instilled through the tube to achieve chemical pleurodesis, such as talc, tetracycline, minocycline, or doxycycline.

The results of chemical pleurodesis tend to be worse than when using surgical approaches, talc pleurodesis has been found to have the best results.

Possible complications

Complications can include any of the following:

  1. Another collapsed lung in the future.
  2. Shock, if there is serious injury or infection, severe inflammation, or fluid in the lung that develops.


Your long-term prognosis depends on the size of the pneumothorax, as well as the cause and treatment required.

In general, a small pneumothorax that does not cause significant symptoms can resolve with minimal observation or treatment.

When a pneumothorax is large, the result of trauma, affects both lungs, or is due to an underlying lung disease, treatment and recovery can be more difficult.

A pneumothorax that keeps coming back can be even more difficult to treat. Get medical attention as soon as possible if your symptoms reappear.

In many cases, less than 5% of people who have undergone surgery in combination with pleurodesis to repair a pneumothorax have a new pneumothorax.