Respiratory bronchiolitis

Respiratory bronchiolitis refers to a histological finding that can be often seen in heavy smokers.

It consists of mild chronic inflammation and accumulation of pigmented macrophages within respiratory bronchioles and related alveoli 1-2. A small amount of fibrosis in the walls of respiratory bronchioles may also be present 2 however these changes are too mild to present with symptoms (by definition).

It is closely related to respiratory bronchiolitis interstitial lung disease (RB-ILD) which represents a more advanced form of the same condition and is also seen almost exclusively amongst smokers. The occurrence of respiratory bronchiolitis in the absence of smoking is extremely uncommon, and its cause is unknown 5. Along the same spectrum of disease is also desquamative interstitial lung disease (DIP) 1 although it is not confined only to smokers. 

Usually respiratory bronchiolitis has no imaging findings, although occasionally minor patchy ground glass opacities and ill-defined centrilobular nodules may be seen, which tend to be more pronounced in the upper zones 2.

It is thought to have been first described by D E Niewoehner is 1974 3,4.

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Article information

rID: 6534
System: Chest
Synonyms or Alternate Spellings:
  • Respiratory bronchiolitis - without interstitial lung disease
  • Inflammation affecting the respiratory bronchioles

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