What is atelectasis of the lungs?

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What is Atelectasis? A Patient-Friendly Explanation

Atelectasis is a condition where part of your lung collapses or doesn't inflate properly, causing that area to become airless and unable to participate in normal breathing. 1, 2

Understanding Your Lungs

Think of your lungs as millions of tiny air sacs (called alveoli) that inflate and deflate with each breath, like tiny balloons. When you have atelectasis, some of these air sacs collapse and stick together, preventing air from getting in. 2

Why Does This Happen?

Atelectasis can occur in several ways:

  • Blocked airways: Something physically blocks your airway—like thick mucus plugs, a foreign object you accidentally inhaled, or a tumor—preventing air from reaching part of your lung 1, 2

  • Compression from outside: Fluid around your lung (pleural effusion), tumors, or other masses can press on your lung tissue from the outside, squeezing it closed 1

  • Loss of lung elasticity: Your lungs normally have a slippery coating (surfactant) that helps keep air sacs open; when this is reduced or absent, the air sacs can stick together and collapse 2, 3

  • Shallow breathing: After surgery or during illness, if you're not taking deep breaths regularly, parts of your lung can gradually collapse 4, 5

Common Situations Where This Occurs

  • After surgery or anesthesia: This is extremely common—up to 90% of people develop some atelectasis during anesthesia, particularly at the base of the lungs 5

  • In hospitalized patients: Especially those lying flat for extended periods or unable to cough effectively 4

  • With lung infections: Pneumonia can cause mucus plugs that block airways 4

  • In premature babies: Newborns with respiratory distress syndrome often develop atelectasis 1

What You Might Experience

  • Shortness of breath or difficulty breathing
  • Chest pain or discomfort
  • Coughing 6
  • In some cases, you may have no symptoms at all, especially if only a small area is affected 2

How It Appears on Imaging

Your doctor will typically see atelectasis on a chest X-ray or CT scan as an area that looks whiter or more opaque than normal lung tissue, often with signs that the affected area has shrunk or pulled nearby structures toward it. 3

The Good News

Atelectasis is usually treatable and often reversible. 4 Treatment focuses on re-expanding the collapsed lung tissue through deep breathing exercises, coughing techniques, changing positions, and addressing whatever caused the collapse in the first place (like removing mucus plugs or draining fluid). 4, 2

References

Guideline

Atelectasis Causes and Mechanisms

Praxis Medical Insights: Practical Summaries of Clinical Guidelines, 2025

Research

Atelectasis: mechanisms, diagnosis and management.

Paediatric respiratory reviews, 2000

Research

Types and mechanisms of pulmonary atelectasis.

Journal of thoracic imaging, 1996

Guideline

Management of Atelectasis

Praxis Medical Insights: Practical Summaries of Clinical Guidelines, 2025

Research

Mechanisms of atelectasis in the perioperative period.

Best practice & research. Clinical anaesthesiology, 2010

Research

Induction and prevention of acceleration atelectasis.

Aviation, space, and environmental medicine, 1987

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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