A collapsed lung, or pneumothorax, occurs when air gathers in the space between the lung and the chest wall, preventing it from fully inflating. It can range from a minor, self-resolving condition to a medical emergency.
Understanding a Collapsed Lung
The lungs are enveloped by a double-layered membrane called the pleura. The inner layer covers the lung surface, and the outer layer lines the chest wall. Between these layers is the pleural space, normally containing a small amount of fluid.
The pleural space normally maintains negative pressure, keeping the lungs expanded. When air enters this space, from a lung leak or outside the body, this pressure is disrupted. Air buildup then compresses the lung, causing it to partially or completely collapse.
A collapsed lung is compressed by surrounding air, impeding its ability to expand and efficiently exchange oxygen and carbon dioxide. The extent of the collapse determines its impact on breathing and overall health.
What Causes a Collapsed Lung?
A collapsed lung can arise from spontaneous, traumatic, or iatrogenic causes. Spontaneous pneumothorax occurs without external injury, divided into primary and secondary types. Primary spontaneous pneumothorax often happens in healthy individuals due to ruptured air sacs (blebs) on the lung surface. Secondary spontaneous pneumothorax develops in people with pre-existing lung conditions.
Secondary spontaneous pneumothorax develops in people with pre-existing lung conditions that weaken lung tissue. Diseases like chronic obstructive pulmonary disease (COPD), asthma, cystic fibrosis, and pneumonia can cause structural changes, such as blocked airways or bulging areas, leading to air release into the pleural space.
Traumatic pneumothorax results from chest wall or lung injury. This includes blunt force trauma (e.g., car accidents, sports) or penetrating injuries (e.g., stab wounds). A fractured rib can also puncture the lung, allowing air to escape into the pleural space.
Iatrogenic pneumothorax is a type of traumatic pneumothorax occurring as a complication of medical procedures. Invasive procedures like lung biopsies, central venous line insertions, or mechanical ventilation can inadvertently puncture the lung or chest wall. The risk increases with invasiveness and can sometimes lead to tension pneumothorax.
Tension pneumothorax is a dangerous form where air enters the pleural space but cannot escape, creating a one-way valve effect. More air becomes trapped with each breath, rapidly building pressure. This collapses the lung and can push the heart and major blood vessels, decreasing blood return and oxygen levels, leading to a life-threatening emergency.
How to Recognize a Collapsed Lung
Recognizing a collapsed lung involves symptoms and medical assessment. Common symptoms include sudden, sharp chest pain, usually on one side, worsening with deep breaths or coughing. Shortness of breath is also prominent, ranging from mild to severe. Other signs can include rapid breathing, a fast heart rate, fatigue, and, in severe cases, bluish skin or lips due to low oxygen levels.
Healthcare providers typically begin with a physical examination. They may notice decreased or absent breath sounds on the affected side of the chest using a stethoscope. Tapping on the chest might produce hollow sounds, indicating air.
Imaging techniques confirm the diagnosis. A chest X-ray is a common initial tool, revealing air in the pleural space and a shrunken lung. For more detailed images or suspected injuries, a computed tomography (CT) scan provides a cross-sectional view. Ultrasound is also valuable, especially in emergency settings, for real-time assessment. Blood tests, such as arterial blood gas, may measure oxygen and carbon dioxide levels to indicate respiratory compromise.
Medical Treatment for a Collapsed Lung
Treatment for a collapsed lung varies by size, symptom severity, and cause. For very small pneumothoraces with minimal symptoms, observation is the initial approach. The body often reabsorbs excess air over several days to weeks, allowing the lung to re-inflate on its own. Supplemental oxygen therapy can accelerate this process.
For larger collapses or significant symptoms, medical intervention removes trapped air. Needle aspiration involves inserting a hollow needle and small flexible tube between the ribs into the pleural space. A syringe then pulls out excess air, allowing the lung to re-expand. The catheter may remain briefly to ensure full re-expansion.
If a larger air volume needs draining or the air continues to leak, a chest tube is inserted. A flexible tube is placed into the chest cavity, connected to a one-way valve or drainage system that continuously removes air. This relieves pressure and allows the lung to re-inflate, remaining in place until the lung fully re-expands and the air leak seals.
For recurrent pneumothorax, persistent air leaks, or ineffective treatments, surgical options are considered. Video-assisted thoracoscopic surgery (VATS) is a minimally invasive procedure using a small camera and instruments through chest incisions. During VATS, surgeons repair air leaks, remove abnormal air sacs (bullae or blebs), and perform pleurodesis. Pleurodesis irritates the pleural layers to make them stick together, eliminating the pleural space and reducing recurrence risk.