A collapsed lung (usually called a pneumothorax) happens when air leaks into the space between the lung and the chest wall, so the lung can’t fully expand and part or all of it “falls in” on itself.

What Can Cause a Collapsed Lung? (Quick Scoop)

1. Big picture: two main ideas

When people say “collapsed lung,” they usually mean pneumothorax , but doctors also sometimes talk about atelectasis , where part of the lung deflates because air can’t get in properly.

  • Pneumothorax = air escapes into the chest cavity and squeezes the lung.
  • Atelectasis = airways are blocked or compressed, so part of the lung shrinks down.

Both can be serious and need medical assessment, especially if there is sudden chest pain or trouble breathing.

2. Common causes of a collapsed lung (pneumothorax)

Here’s a straight‑to‑the‑point list of what can cause a pneumothorax.

2.1 Trauma and injuries

These are situations where something physically damages the chest or lung.

  • Blunt chest trauma: car accidents, hard sports impact, heavy fall to the chest.
  • Penetrating injuries: stab wounds, gunshot wounds, or anything that pierces the chest wall.
  • Rib fractures: sharp broken rib ends can puncture the lung.
  • Medical procedures:
    • Central line placement in the neck or chest
    • Lung biopsy
    • Chest surgery
    • Mechanical ventilation (a breathing machine) where high pressures damage the lung.

Story-style example:
Imagine a person in a car crash whose chest hits the steering wheel hard. A rib cracks and punctures the lung, letting air leak into the chest cavity. Within minutes, they feel sharp chest pain and can’t catch their breath — that air leak is pushing the lung inward and making it collapse.

2.2 Spontaneous pneumothorax (no obvious injury)

Sometimes a lung collapses “out of the blue.” This is called a spontaneous pneumothorax.

There are two major types:

  1. Primary spontaneous pneumothorax (no known lung disease):
    • Often linked to small air blisters called blebs or air cysts near the top of the lung that suddenly burst.
 * More common in:
   * Young, tall, thin people
   * People who smoke
 * Can be triggered by sudden pressure changes, like:
   * High‑altitude travel
   * Scuba or deep‑sea diving
   * Rapid changes in cabin pressure during flights.
  1. Secondary spontaneous pneumothorax (on top of existing lung disease):
    • Occurs in people who already have damaged lungs, and a weak area ruptures.

2.3 Underlying lung diseases

Several lung conditions can weaken lung tissue and make it more likely to tear or leak air.

These include:

  • Chronic obstructive pulmonary disease (COPD) and emphysema
  • Asthma
  • Cystic fibrosis
  • Pneumonia
  • Tuberculosis
  • Lung cancer
  • Interstitial lung diseases or fibrosis
  • Rare cystic lung diseases (e.g., lymphangioleiomyomatosis, Birt‑Hogg‑Dubé syndrome).

In these cases, fragile or cyst‑filled areas of the lung can suddenly rupture, letting air escape into the chest cavity and causing collapse.

2.4 Lifestyle and environmental factors

Certain habits and environments increase the risk of a collapsed lung, usually by stressing or damaging lung tissue.

  • Smoking (including cigarettes and sometimes vaping or other inhaled substances).
  • Recreational inhaled drug use.
  • Sudden changes in pressure:
    • Scuba or deep‑sea diving
    • Flying with rapid altitude changes.

These factors don’t always cause a collapse directly, but they make it more likely in people who have weak lung areas or blebs.

2.5 Mechanical ventilation and hospital care

People in intensive care units on a breathing machine can develop a collapsed lung if the air pressure delivered to the lungs is too high.

  • High airway pressures can over‑distend fragile areas and cause them to tear.
  • This can lead to a more dangerous form called tension pneumothorax , where pressure builds rapidly and can affect the heart and blood flow.

This is one reason why ventilator settings are carefully adjusted and monitored in critical care.

2.6 Less common or special causes

Some other less common but documented triggers include:

  • Air cysts or blebs present from birth or due to genetic factors.
  • Rarely, certain hormonal or menstrual‑related conditions in women (e.g., catamenial pneumothorax, where lung collapse happens around the time of a period).
  • Some connective tissue or collagen vascular diseases.
  • Occasionally, a collapsed lung occurs with no clearly identifiable trigger, even after testing; it is still labeled spontaneous.

3. What about “collapsed lung” from blockage (atelectasis)?

A different kind of “collapse” happens when parts of the lung deflate because air can’t get in — this is atelectasis , and its causes are a bit different.

Key causes of atelectasis include:

  • Mucus plugging airways (common after surgery, infections, or in people who don’t take deep breaths because of pain).
  • Tumors or growths that block an airway so air can’t reach part of the lung.
  • Foreign bodies lodged in the airway (more typical in children).
  • Compression from outside the lung, such as large fluid collections or masses in the chest.

While people often use “collapsed lung” casually for both, pneumothorax and atelectasis are diagnosed and treated differently.

4. When to worry and seek help

A collapsed lung is a medical urgency, not something to watch at home. You should seek emergency care immediately if someone has:

  • Sudden, sharp chest pain, especially on one side
  • Sudden shortness of breath or feeling like you can’t get enough air
  • Fast breathing, fast heart rate, or feeling faint
  • Bluish lips or fingertips
  • Chest injury followed by breathing trouble.

Treatment can range from simple observation and oxygen to placing a needle or chest tube to remove the air, and in some cases surgery to repair or prevent recurrence.

5. Quick FAQ style recap

1. Can stress or anxiety cause a collapsed lung?
Not directly; stress can cause chest pain and fast breathing, but collapse usually needs a physical cause like lung disease, injury, or blebs that rupture.

2. Can you get a collapsed lung from “sleeping wrong”?
That’s extremely unlikely. Most collapses are related to lung structure, trauma, disease, or pressure changes, not body position in bed.

3. Can a collapsed lung happen more than once?
Yes. People who’ve had a spontaneous pneumothorax, smoke, or have underlying lung disease are at higher risk of it happening again.

4. Is a small collapsed lung always obvious?
No. Small pneumothoraces can cause mild symptoms or even be found incidentally on imaging, which is why chest pain or unexplained shortness of breath should be checked out.

Bottom line:
A collapsed lung is usually caused by air leaking into the chest from injury, weak or diseased lung tissue, sudden pressure changes, or medical procedures. If there’s sudden chest pain or breathing trouble, emergency evaluation is essential.

Information gathered from public forums or data available on the internet and portrayed here.