infectious bronchiolitis

Bronchiolitis

• Infectious bronchiolitis with extensive tree-in-bud pattern - Ganzer Fall bei Radiopaedia

Sorrentino S, Infectious bronchiolitis with extensive tree-in-bud pattern. Case study, Radiopaedia.org (Accessed on 29 Jun 2023) https://doi.org/10.53347/rID-19943 • CC by-nc-sa 3.0 (modified)

Radiopaedia • CC-by-nc-sa 3.0 • de

Infectious bronchiolitis refers to subtype of bronchiolitis where there is an definite infective precipitant. It falls under the subgroup in inflammatory bronchiolitides and by some authors is considered a type of cellular bronchiolitis. It tends to be more clinically severe in children than adults.

Pathology

It is characterized histologically by a pattern of acute bronchiolar injury, with epithelial necrosis and inflammation of the bronchiolar walls and intraluminal exudates. There can also be edematous change and fibrosis within bronchiolar walls.

Etiology

viruses
- respiratory syncytial virus (RSV): particularly in children (RSV bronchiolitis)
bacterial species
mycobacterial species
- Mycobacterium tuberculosis: see pulmonary manifestations of tuberculosis
- atypical mycobacterial species
fungal species, e.g. Aspergillus fumigatus, particularly in immunocompromised patients

Radiographic features

CT (HRCT) chest

Intense bronchiolar mural inflammation of cellular bronchiolitis results in centrilobular nodules that are usually associated with the tree-in-bud pattern. There can also be presence of bronchiolar wall thickening.

In some patients, consolidative changes or ground-glass attenuation may also be present .