Atelectasis (summary)

Dr Jeremy Jones et al.

Atelectasis describes loss of lung volume secondary to collapse. It has many causes, the root of which is bronchial obstruction with absorption of distal gas. Atelectasis may be subsegmental, segmental, lobar, or involve and entire lung. 

Reference article

This is a summary article; read more in our article on lobar collapse.

  • pathophysiology
    • bronchial obstruction
      • inflammation, infection, cancer, foreign body
    • distal gaseous absorbsion
    • partial or complete loss of volume distal to obstruction
    • lung parenchyma collapses down
    • associated volume loss
  • investigation
    • chest x-ray
      • quick assessment for segmental or lobar atelectasis
    • CT chest
      • more accurately depicts the involved segment
      • helpful in determining the cause, e.g. cancer

Increased density and volume loss are the characteristic features of atelectasis.

Plain radiograph

The location and severity of collapse can be assessed. It may be challenging to differentiate atelectasis from consolidation or pleural effusion although loss of volume and lack of air-bronchograms are helpful.

Medical student radiology curriculum
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Article Information

rID: 51373
System: Chest
Synonyms or Alternate Spellings:

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Cases and Figures

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    Case 1: right upper lobe collapse in cancer
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    Case 2: left lower lobe collapse
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    Case 3: right middle lobe collapse on CT
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