Obliterative bronchiolitis

Last revised by Joshua Yap on 07 Nov 2022

Obliterative bronchiolitis (OB), also known as bronchiolitis obliterans or constrictive bronchiolitis, is a type of bronchiolitis and refers to bronchiolar inflammation with submucosal peribronchial fibrosis associated with luminal stenosis and occlusions. Obliterative bronchiolitis should not be confused with bronchiolitis obliterans organizing pneumonia (BOOP)

Recognized associations include:

Its cardinal features are progressive breathlessness and a dry cough 14.

The condition is characterized by concentric luminal narrowing of the membranous and respiratory bronchioles as a result of submucosal and peribronchiolar inflammation and fibrosis without any intraluminal granulation tissue or polyps/polyposis. There is an absence of diffuse parenchymal inflammation.

It can result from a number of causes:

  • idiopathic/cryptogenic

  • post-infectious

  • noxious fume inhalation

    • "popcorn lung":  workers of a microwave popcorn plant who had inhaled diacetyl, a chemical used for flavoring, developed obliterative bronchiolitis; the term has since become a colloquial synonym for obliterative bronchiolitis

  • neuroendocrine hyperplasia (pulmonary tumourlets) 4

  • post-transplant patients

A helpful mnemonic is CRITTS.

Chest radiographic findings can be normal or, if abnormal, non-specific. Some associated features include:

  • hyperinflation

  • attenuation of vascular markings

  • occasionally reticular/reticulonodular markings

On HRCT chest, there are often sharply defined, areas of decreased lung attenuation associated with vessels of reduced caliber. These changes represent a combination of air trapping and oligemia. This combination can give a mosaic attenuation pattern. Other features include:

It was first described by the French physician A C Reynaud in 1835 8,9.

Consider:

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Cases and figures

  • Case 1: post-lung transplant
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  • Case 2: chest radiograph
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  • Case 2: HRCT
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  • Case 3: rheumatoid arthritis
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