A pneumothorax, commonly referred to as a “collapsed lung,” occurs when air leaks into the pleural space, the area between the lung and the chest wall. This accumulation of air outside the lung creates pressure that can prevent the lung from fully expanding during breathing.
What Are Pneumothoraces?
The lungs are encased within a double-layered membrane called the pleura, forming a potential space called the pleural cavity. One layer, the visceral pleura, covers the lung surface, while the other, the parietal pleura, lines the inside of the chest wall. Under normal conditions, a slight negative pressure within this pleural space helps keep the lungs inflated, allowing them to expand and contract with each breath.
A pneumothorax disrupts this normal physiological state by allowing air to enter the pleural cavity. This air accumulation increases the pressure within the space, pushing on the lung and causing it to partially or completely collapse. The extent of the lung collapse directly impacts the severity of the condition, with a larger volume of air leading to a greater degree of lung compression. This disruption to lung function can impair the body’s ability to properly oxygenate the blood and maintain adequate ventilation.
Common Causes and Who Is At Risk
Pneumothoraces can arise from various origins, broadly categorized as spontaneous, traumatic, or iatrogenic. Spontaneous pneumothorax occurs without an obvious external cause and is further divided into primary and secondary types. Primary spontaneous pneumothorax often affects tall, thin individuals between 20 and 40 years old, often due to the rupture of small air-filled sacs called blebs or bullae on the lung surface. Smoking significantly increases the risk for primary spontaneous pneumothorax, even in the absence of other lung diseases.
Secondary spontaneous pneumothorax develops in individuals with pre-existing lung conditions that compromise lung tissue. Chronic obstructive pulmonary disease (COPD) is a frequent underlying cause, but other conditions like asthma, cystic fibrosis, tuberculosis, sarcoidosis, and lung cancer also increase susceptibility. These diseases can weaken lung tissue, making it more prone to air leakage into the pleural space. Men are generally more likely to experience a pneumothorax than women.
Traumatic pneumothorax results from physical injury to the chest, such as a gunshot or knife wound, a rib fracture, or blunt force trauma. These injuries can directly puncture the lung or chest wall, allowing air to enter the pleural cavity. A particularly severe form, tension pneumothorax, can occur when injured tissue acts as a one-way valve, trapping air in the pleural space and causing pressure to build with each breath, potentially leading to a life-threatening compromise of heart function.
Iatrogenic pneumothorax occurs as a complication of medical procedures. Common procedures associated with this risk include pleural biopsies, transbronchial lung biopsies, transthoracic pulmonary nodule biopsies, and central venous catheter insertion. Positive pressure ventilation can also create an imbalance of air pressure within the chest, leading to lung collapse. Individuals with a history of pneumothorax are at an increased risk of recurrence, often within one to two years of the initial episode.
Identifying the Symptoms
Pneumothorax symptoms often appear suddenly. A sharp, stabbing chest pain is a common initial indication, often worsening with deep breaths or coughing. This pain is generally localized to one side of the chest, corresponding to the affected lung.
Shortness of breath is another frequent symptom. The severity of these symptoms can vary depending on the amount of lung collapse. A larger pneumothorax may lead to more pronounced symptoms, including chest tightness, rapid breathing, increased heart rate, and easy fatigue. In some cases, a dry, hacking cough may also be present.
How Pneumothoraces Are Diagnosed and Treated
Diagnosing a pneumothorax begins with a physical examination, where a healthcare provider listens to the chest with a stethoscope. Decreased or absent breath sounds on the affected side can suggest the presence of a collapsed lung. Higher than normal levels of carbon dioxide and low levels of oxygen in the blood, often assessed through an arterial blood gas test, can also indicate the condition.
Definitive diagnosis relies on imaging techniques. A chest X-ray is a common first step to visualize air in the pleural cavity and confirm the lung collapse. For more detailed assessment or when other injuries are suspected, a computed tomography (CT) scan may be performed. Ultrasound can also be used as a diagnostic tool.
Treatment approaches for pneumothoraces are tailored to the severity of the condition, its underlying cause, and the patient’s overall health. For small, stable pneumothoraces, particularly those without underlying lung disease, observation with supplemental oxygen therapy may be sufficient, allowing the lung to re-inflate on its own over several weeks. Regular follow-up visits are typically scheduled to monitor progress.
For larger or more symptomatic pneumothoraces, interventions to remove the excess air are necessary. Needle aspiration involves inserting a hollow needle with a flexible tube between the ribs to suction out the air. A chest tube insertion, involving a flexible tube placed into the pleural space and connected to a one-way valve, can continuously remove air until the lung re-expands. In cases of recurrent pneumothorax or persistent air leaks, non-surgical repair methods like pleurodesis, which irritates the pleural tissues to make them stick together and seal leaks, may be considered. In some instances, particularly for recurrent or severe cases, surgical procedures may be performed to address the air leak or remove damaged lung portions.