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Bronchiolitis
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Bronchiolitis is an infection of the lower respiratory tract, the lower part of the tree of passages that air travels through. It is caused mainly by viruses, and it is among the most common illnesses in children 2 years old or younger. Its name comes from the bronchioles, the thin twigs of that tree.
The virus infects the cells that line the inside of the terminal bronchioles, the very last stretches of those twigs. That sets off inflammation: edema appears, meaning swelling of the wall, and more mucus is produced. On top of that, the cells that die slough off and fall into the passage along with the mucus, and they clog it even more. It is like a shower drain where hair and soap build up: the opening closes from the inside.
Respiratory syncytial virus is the main cause. And infants' airways are especially prone to being blocked this way, because they are small in caliber, meaning narrow. The result can be wheezing, a whistling sound when breathing, and air trapping, which is air that gets in and cannot get out.
In brief
Pediatric bronchiolitis is a lower respiratory tract infection caused mainly by viruses; it is among the most common illnesses in children 2 years old or younger.
By infecting the cells lining the terminal bronchioles, the virus causes inflammation with edema and more mucus; dead cells slough into these airways and block them further.
Respiratory syncytial virus is the main cause; infants are especially prone to obstruction because of their small airway caliber, which can lead to wheezing and air trapping.
Sources (1)
- National Center for Biotechnology Information, StatPearls PublishingPediatric Bronchiolitis, StatPearlsPublished
This page explains the topic in general terms; it does not tell anyone what treatment to follow.
Updated