A lung collapse happens when part or all of a lung deflates, preventing it from filling with air normally. There are two distinct ways this occurs: air can leak into the space between your lung and chest wall, forcing the lung inward (called a pneumothorax), or a section of the lung can deflate from the inside when airways become blocked or compressed (called atelectasis). Both interfere with breathing, but they have different causes, different severity levels, and different treatments.
Two Types of Lung Collapse
A pneumothorax happens when air builds up in the pleural space, the thin gap between your lung and the wall of your chest. Normally that space contains only a small amount of fluid that helps your lungs slide smoothly as you breathe. When air enters this space, whether from a puncture, a ruptured air blister on the lung surface, or a chest injury, the pressure pushes against the lung and causes it to collapse partially or fully.
Atelectasis works differently. Instead of air pushing from outside, something blocks or compresses the airways inside the lung. Air that’s already in the tiny air sacs gets absorbed into the bloodstream, and because no new air can get in to replace it, that section of lung deflates. This is common after surgery, especially abdominal or chest procedures, when shallow breathing and mucus buildup prevent parts of the lung from staying inflated. It can also happen when a tumor or foreign object blocks a bronchial tube.
When people search for “lung collapse,” they’re usually thinking of a pneumothorax, since it’s more dramatic and more likely to send someone to the emergency room. The rest of this article focuses primarily on pneumothorax, though many of the symptoms overlap.
What Causes a Pneumothorax
A pneumothorax can happen to anyone, but certain people are at significantly higher risk. The most common form in otherwise healthy people is called a primary spontaneous pneumothorax, meaning it occurs without any obvious injury or lung disease. It typically strikes tall, thin young men between 20 and 40. Researchers believe that rapid chest growth during adolescent growth spurts can create small air blisters (called blebs) on the surface of the lung. These blisters can rupture without warning, letting air escape into the pleural space.
Smoking is one of the strongest modifiable risk factors. The risk climbs with both the number of cigarettes smoked per day and the total years of smoking, even in people who haven’t developed emphysema or other visible lung damage. Certain genetic conditions also play a role. Birt-Hogg-Dube syndrome, a rare inherited disorder, causes thin-walled air sacs in the lung tissue that are prone to rupturing. Other cystic lung diseases carry similar risks. Some types of pneumothorax appear to run in families even without a known genetic syndrome.
Traumatic pneumothorax, the other major category, results from a physical injury to the chest. Car accidents, stab wounds, broken ribs, and even certain medical procedures like a lung biopsy or the placement of a central IV line can puncture the lung and allow air into the pleural space.
Symptoms to Recognize
The hallmark symptoms are sudden, sharp chest pain on one side and shortness of breath that comes on quickly. The pain often worsens with deep breaths. In a small pneumothorax, symptoms can be mild enough that some people wait hours or even days before seeking care. Larger collapses cause more obvious distress: rapid heart rate, a feeling of tightness across the chest, and visible difficulty breathing.
In older adults or people with existing lung disease, the symptoms can be harder to pin down. Someone with chronic obstructive pulmonary disease, for example, may already experience baseline shortness of breath, which makes a new pneumothorax easy to miss or attribute to a flare-up. Any sudden worsening of breathing in someone with lung disease warrants urgent evaluation.
Tension Pneumothorax
The most dangerous form is a tension pneumothorax, where air keeps entering the pleural space but can’t escape, essentially creating a one-way valve. As pressure builds, it compresses not just the affected lung but also pushes the heart and major blood vessels toward the opposite side of the chest. This compression reduces blood flow back to the heart, causing a rapid drop in blood pressure and shock. Signs include distended neck veins, the windpipe shifting visibly to one side, and rapidly worsening vital signs. A tension pneumothorax is a life-threatening emergency that requires immediate intervention to release the trapped air.
How It’s Diagnosed and Treated
A chest X-ray is usually the first step. Doctors look for the visible edge of the collapsed lung and measure the gap between the lung surface and the chest wall. How that gap is measured actually varies by country. American guidelines define a “large” pneumothorax as 3 cm or more from the top of the lung to the top of the chest cavity. British guidelines use a different landmark, measuring more than 2 cm between the lung margin and chest wall at the middle of the lung. These measurement differences lead to different treatment recommendations, which is worth knowing if you’re reading conflicting information online.
For a small pneumothorax in a stable patient, observation alone is sometimes enough. The leaked air gradually reabsorbs on its own over days to weeks, and repeat X-rays track the progress. Supplemental oxygen speeds up this reabsorption.
Larger collapses require active removal of the trapped air. One approach is needle aspiration, where a needle is inserted through the chest wall to draw out the air. The other is a chest tube, a flexible tube placed between the ribs and connected to a drainage system that continuously removes air until the lung re-expands. American guidelines generally favor the chest tube approach, while British guidelines lean toward trying needle aspiration first.
Surgery for Recurring Collapse
Recurrence is one of the biggest concerns after a first pneumothorax. A systematic review in the European Respiratory Journal found that roughly 29% of people who experience a primary spontaneous pneumothorax will have another one within a year. The overall recurrence rate across all follow-up periods is about 32%. In other words, nearly one in three people will go through it again.
For people with recurrent collapses, surgery becomes the standard recommendation. The most common procedure is a minimally invasive operation performed through small incisions in the chest wall. During surgery, the surgeon removes the air blisters responsible for the leaks and then irritates the surface of the lung so it scars and adheres to the chest wall, making future collapse much harder. When a chemical irritant like talc is applied during the procedure, recurrence rates drop dramatically, to between 0% and 3.2% in studies involving over 2,300 patients. That’s a significant improvement over the 29% recurrence rate with no intervention.
Newer surgical techniques using a single small incision rather than the traditional three incisions appear to result in shorter hospital stays, though both approaches have similar long-term success rates.
Recovery and Activity Restrictions
Recovery time depends on the severity of the collapse and the treatment required. A small pneumothorax managed with observation alone may resolve in one to two weeks. If a chest tube was placed, most people spend a few days in the hospital while the tube drains and the lung re-expands, followed by several weeks of gradually returning to normal activity. Post-surgical recovery typically takes a few weeks longer.
Air travel is one restriction that catches people off guard. The lower cabin pressure in an airplane can cause any remaining trapped air to expand, potentially worsening or retriggering a collapse. British Thoracic Society guidelines state that passengers should not fly until at least 7 days after a chest X-ray confirms the pneumothorax has fully resolved. If your collapse happened during or after a medical procedure, the same one-week-after-resolution rule applies.
Scuba diving carries an even greater risk due to the extreme pressure changes involved. Most pulmonologists advise against ever returning to scuba diving after a spontaneous pneumothorax unless corrective surgery has been performed, and even then, the guidance varies. Contact sports and heavy lifting are also typically restricted for several weeks after recovery to give the lung time to heal and seal completely.
Quitting smoking is the single most effective thing you can do to reduce your risk of a first or repeat collapse. Because smoking independently raises pneumothorax risk regardless of other lung conditions, stopping at any point lowers your odds significantly.