Passive atelectasis
Passive atelectasis, also known as relaxation atelectasis, refers to a form of lung atelectasis due to loss of the negative pressure state in the pleural space. With a loss of the negative intrapleural pressure, the lung is no longer held against the chest wall and is said to relax back to its normal volume. There may not be a significant increase in density from the atelectasis as perfusion of the affected lung also decreases.
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Clinical presentation
The clinical presentation would depend on the extent of atelectasis and how quickly it develops. Small and gradually developing areas of atelectasis may be asymptomatic or present as a non-productive cough. Larger areas that develop more quickly can present with features of hypoxia and respiratory failure.
Physical examination of the lung may reveal diminished movement of the affected area, dullness on percussion, decreased or absent breath sounds, and deviation of the trachea to the affected site.
Pathology
Etiology
Causes of passive atelectasis may be grouped into three main categories:
- simple pneumothorax
-
diaphragmatic abnormalities
- diaphragmatic hernia
- paralysis of the diaphragm
- congenital eventration of the diaphragm
- conditions of hypoventilation
- pleural effusion
- hemothorax
- pleural tumor
- chest wall mass lesion
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atelectasis
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Chest
- imaging techniques
-
chest x-ray
-
approach
- adult
- pediatric
- neonatal
-
airspace opacification
- differential diagnoses of airspace opacification
- lobar consolidation
-
atelectasis
- mechanism-based
- morphology-based
- lobar lung collapse
- chest x-ray in the exam setting
- cardiomediastinal contour
- chest radiograph zones
- tracheal air column
- fissures
- normal chest x-ray appearance of the diaphragm
- nipple shadow
-
lines and stripes
- anterior junction line
- posterior junction line
- right paratracheal stripe
- left paratracheal stripe
- posterior tracheal stripe/tracheo-esophageal stripe
- posterior wall of bronchus intermedius
- right paraspinal line
- left paraspinal line
- aortic-pulmonary stripe
- aortopulmonary window
- azygo-esophageal recess
- spaces
- signs
- air bronchogram
- big rib sign
- Chang sign
- Chen sign
- coin lesion
- continuous diaphragm sign
- dense hilum sign
- double contour sign
- egg-on-a-string sign
- extrapleural sign
- finger in glove sign
- flat waist sign
- Fleischner sign
- ginkgo leaf sign
- Golden S sign
- Hampton hump
- haystack sign
- hilum convergence sign
- hilum overlay sign
- Hoffman-Rigler sign
- holly leaf sign
- incomplete border sign
- juxtaphrenic peak sign
- Kirklin sign
- medial stripe sign
- melting ice cube sign
- more black sign
- Naclerio V sign
- Palla sign
- pericardial fat tag sign
- Shmoo sign
- silhouette sign
- snowman sign
- spinnaker sign
- steeple sign
- straight left heart border sign
- third mogul sign
- tram-track sign
- walking man sign
- water bottle sign
- wave sign
- Westermark sign
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approach
- HRCT
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chest x-ray
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bronchiectasis
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tracheal stenosis
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bronchial stenosis
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tracheal stenosis
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interstitial lung disease (ILD)
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hypersensitivity pneumonitis
- acute hypersensitivity pneumonitis
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- chronic hypersensitivity pneumonitis
- etiology
- bird fancier's lung: pigeon fancier's lung
- farmer's lung
- cheese workers' lung
- bagassosis
- mushroom worker’s lung
- malt worker’s lung
- maple bark disease
- hot tub lung
- wine maker’s lung
- woodsman’s disease
- thatched roof lung
- tobacco grower’s lung
- potato riddler’s lung
- summer-type pneumonitis
- dry rot lung
- machine operator’s lung
- humidifier lung
- shower curtain disease
- furrier’s lung
- miller’s lung
- lycoperdonosis
- saxophone lung
-
idiopathic interstitial pneumonia (mnemonic)
- acute interstitial pneumonia (AIP)
- cryptogenic organizing pneumonia (COP)
- desquamative interstitial pneumonia (DIP)
- non-specific interstitial pneumonia (NSIP)
- idiopathic pleuroparenchymal fibroelastosis
- lymphoid interstitial pneumonia (LIP)
- respiratory bronchiolitis–associated interstitial lung disease (RB-ILD)
- usual interstitial pneumonia / idiopathic pulmonary fibrosis (UIP/IPF)
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pneumoconioses
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lung cancer
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non-small-cell lung cancer
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adenocarcinoma
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non-small-cell lung cancer