What Is Atelectasis?

Atelectasis is a lung condition that happens when your airways or the tiny sacs at the end of them don’t expand the way they should when you breathe. It’s one of the conditions that can cause a collapsed lung.

Your lungs are where your body takes in oxygen and gets rid of carbon dioxide. When you breathe in, air flows into your windpipe, or trachea. The trachea splits into two channels called bronchi, and each bronchus goes to a lung.

Inside your lungs, those airways divide again and again into smaller tubes called bronchioles. At the end of the smallest bronchioles are tiny sacs called alveoli. Here, your blood dumps carbon dioxide and picks up fresh oxygen to carry to the cells in your body.

When you breathe in and out, your lungs inflate and deflate like balloons. But if your airways get blocked or something puts pressure on your lungs, they might not inflate the way they should. Doctors call that condition atelectasis. It can be life-threatening in small children or people who have another lung problem.

Atelectasis Symptoms

If you have atelectasis, you'll feel like you can’t get enough air. Other symptoms include:

If you’re having trouble breathing, get medical help right away.

Causes of Atelectasis

It’s common to get atelectasis after you have surgery. The medication that puts you to sleep can also affect how your lungs work, and the surgery itself can make it hurt to breathe deeply. Other causes include:

  • Pressure from outside your lungs, like from a tumor or a body cast
  • Pneumonia
  • Serious lung conditions

Risk Factors for Atelectasis

Some people may be more likely than others to have atelectasis. Things that can raise your chances of it include:


Types of Atelectasis

The two main types of atelectasis are obstructive (also called resorptive) and nonobstructive.

Obstructive atelectasis happens when something, like mucus or a tumor, blocks your airway.

Types of nonobstructive atelectasis include:

  • Relaxation or compressive: The lining of your chest wall and the surface of your lungs are normally in close contact, keeping your lungs expanded. But if fluid or air builds up and separates them, your lungs can pull inward, and your alveoli can lose air. Depending on where this happens in your lung, it's either relaxation or compressive atelectasis.
  • Adhesive: The fluid that lines the alveoli in your lungs has a material in it called pulmonary surfactant. It helps your lungs in several ways, including keeping the alveoli stable and able to work. If there's a problem with this material (like if your body doesn’t make enough of it), the alveoli can collapse. When that happens, it's called adhesive atelectasis. It can be caused by serious lung problems such as respiratory distress syndrome or a bruised lung (pulmonary contusion).
  • Cicatricial: This type of atelectasis is when the tissue that makes up your lungs has scars that keep them from being able to hold as much air as they should. This scarring can happen because of certain serious lung conditions like sarcoidosis.
  • Replacement: This is when your alveoli are filled by a tumor, and that causes an area of your lung to collapse.
  • Acceleration: When jet pilots fly straight up really fast (between 5 and 9 G-forces), the acceleration can close the airways in their lungs, leading to this type of atelectasis. It can make it hard to breathe and cause chest pain and coughing.
  • Rounded (also called folded lung): This type is linked to pleural diseases, conditions that affect the thin tissue that lines your chest cavity and surrounds your lungs (the pleura). One of the most common causes is asbestosis, when you breathe in asbestos over a long period of time and this damages the pleura.

Atelectasis Diagnosis

If your doctor thinks you might have atelectasis, they'll probably recommend a chest X-ray. A collapsed lung may look partly or completely white on the image.

If your airways are blocked, your doctor also might use a device called a bronchoscope to look into your lungs and find the problem. A bronchoscope is a thin tube with a light and a camera that slides down your throat and into your airways.


Atelectasis Treatment and Recovery

If a tumor or another health condition is causing the collapsed lung, your doctor will treat that. If something is blocking your airways, like mucus, they can remove it with a bronchoscope. For other problems, they might give you medicine through an inhaler, tap on your chest to break up mucus, or have you lie on your unaffected side or in a position where your head is lower than your chest to drain mucus.

Your doctor or nurse may also show you how to do some exercises that will help you breathe better.

After treatment, a collapsed lung usually begins working the way it should again, but atelectasis can cause permanent damage in some cases.

Complications of Atelectasis

If atelectasis isn’t treated, it can have complications including:

  • Pneumonia. Mucus can cause an infection in your lung.
  • Respiratory failure
  • Fluid buildup
  • Low blood oxygen. If your lungs can’t inflate right, they might not be able to get enough oxygen into your blood.

WebMD Medical Reference Reviewed by Paul Boyce, MD on October 29, 2019



National Heart, Lung, and Blood Institute: “Atelectasis,” “Bronchoscopy.”

Johns Hopkins Medicine: “Atelectasis.”

Continuing Education in Anaesthesia Critical Care & Pain: “Pulmonary atelectasis in anaesthesia and critical care.”

Cleveland Clinic: “Atelectasis.”

Mayo Clinic: “Atelectasis.”

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