Atelectasis is a collapse of the air sacs in the lungs. It may occur in part or all of the lung. It can make breathing difficult.
The Lungs (Cut-away View)
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Atelectasis is caused by:
Things that may raise the risk of atelectasis are:
Atelectasis may or may not cause symptoms. A larger area of collapse is more apt to cause symptoms. In this case, symptoms may be:
The doctor will ask about your symptoms and health history. A physical exam will be done. This may include listening to the lungs for changes in the normal sounds.
The airways may be viewed with:
Other tests may be needed to confirm or rule out the cause of atelectasis.
The goal is to treat the underlying cause and maintain enough oxygen. The collapsed lung usually expands once the cause has been corrected. Mild atelectasis often goes away on its own without treatment.
Treatments options may be:
To help lower the risk of atelectasis:
American Lung Association
National Heart, Lung, and Blood Institute
The Lung Association
Atelectasis. Merck Manual Professional Version website. Available at:
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Accessed March 30, 2021.
Chest x-ray patterns in the differential diagnosis of lung disorders. EBSCO DynaMed website. Available at: https://www.dynamed.com/evaluation/chest-x-ray-patterns-in-the-differential-diagnosis-of-lung-disorders. Accessed March 30, 2021.
Explore atelectasis. National Heart, Lung, and Blood Institute website. Available at: https://www.nhlbi.nih.gov/health/health-topics/topics/atl. Accessed March 30, 2021.
Marini JJ. Acute lobar atelectasis. Chest. 2019;155(5):1049-1058.
Last reviewed December 2020 by
EBSCO Medical Review Board
David L. Horn, MD, FACP
Last Updated: 3/30/2021