Lobar lung collapse
Updates to Article Attributes
Lobar collapse refers to the collapse of an entire lobe of the lung. As such it is a subtype of atelectasis (although collapse is not entirely synonymous is atelectasis), which is a more generic term for 'incomplete expansion'. Individual lobes of the lung may collapse due to obstruction of the supplying bronchus.
Pathology
Aetiology
- luminal
- mural
-
extrinsic
- compression by adjacent mass
Radiographic features
Plain radiograph
Generally there is pulmonary opacification but the appearance on chest x-ray varies according to the lobe involved and are discussed separately:
- right upper lobe collapse
- right middle lobe collapse
- right lower lobe collapse
- left upper lobe collapse
- left lower lobe
collapse lingularcollapse
Some features, however, are generic markers of volume loss and are helpful in directing ones attention to the collapse, as well as enabling distinction from opacification of the lobe without collapse (i.e. consolidation e.g. lobar pneumonia). These features include 5,9:
- direct signs
- displacement of fissures
- crowding of pulmonary vessels
- indirect signs
- elevation of the ipsilateral hemidiaphragm
- crowding of the ipsilateral ribs
- shift of the mediastinum towards the side of atelectasis
- compensatory hyperinflation of normal lobes
- hilar displacement towards the collapse
- shifting granuloma sign
CT
Lobar collapse is usually trivially easy to identify on CT, but identification of the cause is not always easy, as the collapsed lung can make identification of an obstructing lesion difficult.
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