obliterative bronchiolitis

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. OB should not be confused with bronchiolitis obliterans organizing pneumonia (BOOP).

Epidemiology

Associations

Recognized associations include:

Clinical presentation

Its cardinal features are progressive breathlessness and a dry cough .

Pathology

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.

Etiology

It can result from number of causes:

Mnemonic: CRITTS

Radiographic features

Plain radiograph

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

  • hyperinflation
  • attenuation of vascular markings
  • occasionally reticular/reticulonodular markings
CT

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:

History and etymology

It was first described by the French physician AC Reynaud in 1835 .

Differential diagnosis

Consider: