Mucoid impaction (lung)
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At the time the article was created Yuranga Weerakkody had no recorded disclosures.View Yuranga Weerakkody's current disclosures
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Mucoid impaction, also referred to as mucous plugging, refers to airway filling by retained secretions. When the bronchi become dilated due to mucoid impaction, the term bronchocele can be used 6.
Mucoid impaction may result from either obstructive or non-obstructive causes, although the latter does eventually obstruct the bronchi as well:
Non-obstructive causes are infectious or inflammatory in nature:
cystic fibrosis: due to impaired ciliary movement and thick secretions
asthma: due to increased mucus production
other acquired conditions
Mucoid impaction may appear as a branching tubular opacity that is distinct from the normal vascular shadows. This classic feature is the finger-in-glove sign and is also seen on CT. It can sometimes prove difficult to diagnose on plain radiography.
The appearance on CT can be variable, depending on where the mucous plugging occurs (i.e. central or peripheral airways).
Mucous plugs appear as fluid density material often located dependently within the bronchus, sometimes with internal gas.
The classic feature seen when plugged mucus extends along large branching airways is the finger-in-glove sign.
Several key additional features can also occur:
distal lung collapse: from collateral air drift; this has not yet developed in infants and young children, which is why the distal lung is rather hyperlucent in this population (e.g. congenital bronchial atresia, foreign body aspiration)
Treatment and prognosis
Prolonged mucous plugging can lead to bronchial dilatation and bronchiectasis.
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